draft-ietf-ecrit-phonebcp-03.txt   draft-ietf-ecrit-phonebcp-04.txt 
ecrit B. Rosen ecrit B. Rosen
Internet-Draft NeuStar Internet-Draft NeuStar
Intended status: Standards Track J. Polk Intended status: Standards Track J. Polk
Expires: May 22, 2008 Cisco Systems Expires: August 28, 2008 Cisco Systems
November 19, 2007 February 25, 2008
Best Current Practice for Communications Services in support of Best Current Practice for Communications Services in support of
Emergency Calling Emergency Calling
draft-ietf-ecrit-phonebcp-03 draft-ietf-ecrit-phonebcp-04
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on May 22, 2008. This Internet-Draft will expire on August 28, 2008.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2008).
Abstract Abstract
The IETF and other standards organization have efforts targeted at The IETF and other standards organization have efforts targeted at
standardizing various aspects of placing emergency calls on IP standardizing various aspects of placing emergency calls on IP
networks. This memo describes best current practice on how devices, networks. This memo describes best current practice on how devices,
networks and services should use such standards to make emergency networks and services should use such standards to make emergency
calls. calls.
Table of Contents Table of Contents
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6.3. Who adds location, endpoint or proxy . . . . . . . . . . . 7 6.3. Who adds location, endpoint or proxy . . . . . . . . . . . 7
6.4. Location and references to location . . . . . . . . . . . 7 6.4. Location and references to location . . . . . . . . . . . 7
6.5. End system location configuration . . . . . . . . . . . . 7 6.5. End system location configuration . . . . . . . . . . . . 7
6.6. When location should be configured . . . . . . . . . . . . 8 6.6. When location should be configured . . . . . . . . . . . . 8
6.7. Conveying location in SIP . . . . . . . . . . . . . . . . 9 6.7. Conveying location in SIP . . . . . . . . . . . . . . . . 9
6.8. Location updates . . . . . . . . . . . . . . . . . . . . . 10 6.8. Location updates . . . . . . . . . . . . . . . . . . . . . 10
6.9. Multiple locations . . . . . . . . . . . . . . . . . . . . 10 6.9. Multiple locations . . . . . . . . . . . . . . . . . . . . 10
6.10. Location validation . . . . . . . . . . . . . . . . . . . 11 6.10. Location validation . . . . . . . . . . . . . . . . . . . 11
6.11. Default location . . . . . . . . . . . . . . . . . . . . . 11 6.11. Default location . . . . . . . . . . . . . . . . . . . . . 11
6.12. Other location considerations . . . . . . . . . . . . . . 11 6.12. Other location considerations . . . . . . . . . . . . . . 11
6.13. LIS and LoST Discovery . . . . . . . . . . . . . . . . . . 11 7. LIS and LoST Discovery . . . . . . . . . . . . . . . . . . . . 11
7. Uninitialized devices . . . . . . . . . . . . . . . . . . . . 12
8. Routing the call to the PSAP . . . . . . . . . . . . . . . . . 12 8. Routing the call to the PSAP . . . . . . . . . . . . . . . . . 12
9. Signaling of emergency calls . . . . . . . . . . . . . . . . . 13 9. Signaling of emergency calls . . . . . . . . . . . . . . . . . 13
9.1. Use of TLS . . . . . . . . . . . . . . . . . . . . . . . . 13 9.1. Use of TLS . . . . . . . . . . . . . . . . . . . . . . . . 13
9.2. SIP signaling requirements for User Agents . . . . . . . . 14 9.2. SIP signaling requirements for User Agents . . . . . . . . 13
9.3. SIP signaling requirements for proxy servers . . . . . . . 15 9.3. SIP signaling requirements for proxy servers . . . . . . . 15
10. Call backs . . . . . . . . . . . . . . . . . . . . . . . . . . 16 10. Call backs . . . . . . . . . . . . . . . . . . . . . . . . . . 15
11. Mid-call behavior . . . . . . . . . . . . . . . . . . . . . . 16 11. Mid-call behavior . . . . . . . . . . . . . . . . . . . . . . 16
12. Call termination . . . . . . . . . . . . . . . . . . . . . . . 16 12. Call termination . . . . . . . . . . . . . . . . . . . . . . . 16
13. Disabling of features . . . . . . . . . . . . . . . . . . . . 17 13. Disabling of features . . . . . . . . . . . . . . . . . . . . 16
14. Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 14. Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
15. Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 15. Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
16. Security Considerations . . . . . . . . . . . . . . . . . . . 19 16. Security Considerations . . . . . . . . . . . . . . . . . . . 18
17. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19 17. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18
18. Normative References . . . . . . . . . . . . . . . . . . . . . 19 18. Normative References . . . . . . . . . . . . . . . . . . . . . 19
Appendix A. BCP Requirements Sorted by Responsible Party . . . . 24 Appendix A. BCP Requirements Sorted by Responsible Party . . . . 24
A.1. Requirements of End Devices . . . . . . . . . . . . . . . 24 A.1. Requirements of End Devices . . . . . . . . . . . . . . . 24
A.2. Requirements of Service Providers . . . . . . . . . . . . 32 A.2. Requirements of Service Providers . . . . . . . . . . . . 32
A.3. Requirements of Access Networks . . . . . . . . . . . . . 36 A.3. Requirements of Access Network . . . . . . . . . . . . . . 37
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 39 A.4. Requirements of Intermediate Devices . . . . . . . . . . . 39
Intellectual Property and Copyright Statements . . . . . . . . . . 40 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 42
Intellectual Property and Copyright Statements . . . . . . . . . . 43
1. Terminology 1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
This document uses terms from [RFC3261], This document uses terms from [RFC3261],
[I-D.ietf-ecrit-requirements] and [I-D.ietf-ecrit-framework]. [I-D.ietf-ecrit-requirements] and [I-D.ietf-ecrit-framework].
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BCP succinctly describes the requirements of end devicesand BCP succinctly describes the requirements of end devicesand
applications (requirements prefaced by "ED-"), access networks applications (requirements prefaced by "ED-"), access networks
(requirements prefaced by "AN-", service providers (requirements (requirements prefaced by "AN-", service providers (requirements
prefaced by "SP-") and PSAPs to achieve globally interoperable prefaced by "SP-") and PSAPs to achieve globally interoperable
emergency calling on the Internet. emergency calling on the Internet.
This document also defines requirements for "Intermediate" devices This document also defines requirements for "Intermediate" devices
which exist between end devices or applications and the access which exist between end devices or applications and the access
network. For example, a home router is an "Intermediate" device. network. For example, a home router is an "Intermediate" device.
Reporting location on an emergency call (see Section 6 may depend on Reporting location on an emergency call (see Section 6 may depend on
the ability of such intermediate devices to meet these requirements. the ability of such intermediate devices to meet the requirements
prefaced by "INT-".
3. Overview of how emergency calls are placed 3. Overview of how emergency calls are placed
An emergency call can be distinguished (Section 5) from any other An emergency call can be distinguished (Section 5) from any other
call by a unique Service URN[I-D.ietf-ecrit-service-urn], which is call by a unique Service URN[I-D.ietf-ecrit-service-urn], which is
placed in the call set-up signaling when a home or visited emergency placed in the call set-up signaling when a home or visited emergency
dial string is detected. Because emergency services are local to dial string is detected. Because emergency services are local to
specific geographic regions, a caller must obtain his location specific geographic regions, a caller must obtain his location
(Section 6) prior to making emergency calls. To get this location, (Section 6) prior to making emergency calls. To get this location,
either a form of measuring (e.g., GPS) (Section 6.2.3) device either a form of measuring (e.g., GPS) (Section 6.2.3) device
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to civic) from the form of location the determination mechanism to civic) from the form of location the determination mechanism
supplied. supplied.
6.2. Location Determination 6.2. Location Determination
ED-14/INT-3/AN-2 Any suitable location determination mechanism MAY be ED-14/INT-3/AN-2 Any suitable location determination mechanism MAY be
used. used.
6.2.1. User-entered location information 6.2.1. User-entered location information
ED-15/INT-3/AN-3 Devices, intermediate Devices and/or access networks ED-15/INT-4/AN-3 Devices, intermediate Devices and/or access networks
SHOULD support a manual method to "override" the location the access SHOULD support a manual method to "override" the location the access
network determines. Where a civic form of location is provided, all network determines. Where a civic form of location is provided, all
fields in the PIDF-LO [RFC4119] and fields in the PIDF-LO [RFC4119] and [RFC5139] MUST be able to be
[I-D.ietf-geopriv-revised-civic-lo] MUST be able to be specified. specified.
6.2.2. Access network "wire database" location information 6.2.2. Access network "wire database" location information
AN-4 Access networks supporting copper, fiber or other hard wired IP AN-4 Access networks supporting copper, fiber or other hard wired IP
packet service SHOULD support location configuration. If the network packet service SHOULD support location configuration. If the network
does not support location configuration, it MUST require every device does not support location configuration, it MUST require every device
that connects to the network to support end system measured location. that connects to the network to support end system measured location.
AN-5/INT-4 Access networks and intermediate devices providing wire AN-5/INT-5 Access networks and intermediate devices providing wire
database location information SHOULD provide interior location data database location information SHOULD provide interior location data
(building, floor, room, cubicle) where possible. It is RECOMMENDED (building, floor, room, cubicle) where possible. It is RECOMMENDED
that interior location be provided when spaces exceed approximately that interior location be provided when spaces exceed approximately
650 square meters. 650 square meters.
AN-6/INT-5 Access networks and intermediate devices (including AN-6/INT-6 Access networks and intermediate devices (including
enterprise networks) which support intermediate range wireless enterprise networks) which support intermediate range wireless
connections (typically 100m or less of range) and which do not connections (typically 100m or less of range) and which do not
support a more accurate location determination mechanism such as support a more accurate location determination mechanism such as
triangulation, MUST support location configuration where the location triangulation, MUST support location configuration where the location
of the access point is reflected as the location of the clients of of the access point is reflected as the location of the clients of
that access point. Where the access network provides location that access point. Where the access network provides location
configuration, intermediate devices MUST either be transparent to it, configuration, intermediate devices MUST either be transparent to it,
or provide an interconnected client for the supported configuration or provide an interconnected client for the supported configuration
mechanism and a server for a configuration protocol supported by end mechanism and a server for a configuration protocol supported by end
devices upstream of the intermediate device devices upstream of the intermediate device
6.2.3. End-system measured location information 6.2.3. End-system measured location information
ED-16/INT-6 Devices MAY support end-system measured location. ED-16/INT-7 Devices MAY support end-system measured location.
Uncertainty of less than 100 m with 95% confidence SHOULD be Uncertainty of less than 100 m with 95% confidence SHOULD be
available for dispatch. available for dispatch.
ED-17/INT-7/AN-7 Devices that support endpoint measuring of location ED-17/INT-8/AN-7 Devices that support endpoint measuring of location
MUST have at least a coarse location capability (typically <1km MUST have at least a coarse location capability (typically <1km
accuracy when not location hiding) at all times for routing of calls. accuracy when not location hiding) at all times for routing of calls.
This mechanism MAY be a service provided by the access network. This mechanism MAY be a service provided by the access network.
6.2.4. Network-measured location information 6.2.4. Network-measured location information
AN-8 Access networks MAY provide network-measured location AN-8 Access networks MAY provide network-measured location
determination. Wireless access network which do not support network determination. Wireless access network which do not support network
measured location MUST require that all devices connected to the measured location MUST require that all devices connected to the
network have end-system measured location. Uncertainty of less than network have end-system measured location. Uncertainty of less than
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at least a coarse location (typically <1km when not location hiding) at least a coarse location (typically <1km when not location hiding)
capability at all times for routing of calls. capability at all times for routing of calls.
AN-10 Access networks with range of <10 meters MUST provide a AN-10 Access networks with range of <10 meters MUST provide a
location to mobile devices connected to it. The location provided location to mobile devices connected to it. The location provided
SHOULD be that of the access point location unless a more accurate SHOULD be that of the access point location unless a more accurate
mechanism is provided. mechanism is provided.
6.3. Who adds location, endpoint or proxy 6.3. Who adds location, endpoint or proxy
ED-18/INT-8 Endpoints SHOULD do configure their own location. ED-18/INT-9 Endpoints SHOULD do configure their own location.
SP-12 Proxies MAY provide location on behalf of devices if: SP-12 Proxies MAY provide location on behalf of devices if:
o The proxy has a relationship with all access networks the device o The proxy has a relationship with all access networks the device
could connect to, and the relationship allows it to obtain could connect to, and the relationship allows it to obtain
location. location.
o The proxy has an identifier, such as an IP address, that can be o The proxy has an identifier, such as an IP address, that can be
used by the access network to determine the location of the used by the access network to determine the location of the
endpoint, even in the presence of NAT and VPN tunnels that may endpoint, even in the presence of NAT and VPN tunnels that may
obscure the identifier between the access network and the service obscure the identifier between the access network and the service
provider. provider.
ED-19/INT-9/SP-13 Where proxies provide location on behalf of ED-19/INT-10/SP-13 Where proxies provide location on behalf of
endpoints, the the service provider MUST ensure that either the end endpoints, the the service provider MUST ensure that either the end
device is provided with the local dial strings for its current device is provided with the local dial strings for its current
location (where the end device recognizes dial strings), or the location (where the end device recognizes dial strings), or the
service provider proxy MUST detect the appropriate local dial strings service provider proxy MUST detect the appropriate local dial strings
at the time of the call. at the time of the call.
6.4. Location and references to location 6.4. Location and references to location
ED-20/INT-10 Devices SHOULD be able to accept and forward location by ED-20/INT-11 Devices SHOULD be able to accept and forward location by
value or by reference. An end device that receives location by value or by reference. An end device that receives location by
reference (and does not also get the corresponding value) MUST be reference (and does not also get the corresponding value) MUST be
able to perform a dereference operation to obtain a value. able to perform a dereference operation to obtain a value.
6.5. End system location configuration 6.5. End system location configuration
ED-21/INT-11 Devices MUST support all of: DHCP location options ED-21/INT-12 Devices MUST support all of: DHCP location options
[RFC4676] and [RFC3825], HELD [RFC4676] and [RFC3825], HELD
[I-D.ietf-geopriv-http-location-delivery] and LLDP-MED [LLDP-MED]. [I-D.ietf-geopriv-http-location-delivery] and LLDP-MED [LLDP-MED].
AN-11/INT-12 The access network MUST support at least one of: DHCP AN-11/INT-13 The access network MUST support at least one of: DHCP
location options, HELD or LLDP-MED. location options, HELD or LLDP-MED.
AN-12/INT-13 Where a router is employed between a LAN and WAN in a AN-12/INT-14 Where a router is employed between a LAN and WAN in a
small (less than approximately 650 square meters) area, the router small (less than approximately 650 square meters) area, the router
MUST be transparent to the location provided by the WAN to the LAN. MUST be transparent to the location provided by the WAN to the LAN.
This may mean the router must obtain location as a client from the This may mean the router must obtain location as a client from the
WAN, and supply an LCP server to the LAN with the location it WAN, and supply an LCP server to the LAN with the location it
obtains. Where the area is larger, the LAN MUST have a location obtains. Where the area is larger, the LAN MUST have a location
configuration mechanism meeting this BCP. configuration mechanism meeting this BCP.
ED-22/INT-14 Endpoints SHOULD try all LCPs supported by the device in ED-22/INT-15 Endpoints SHOULD try all LCPs supported by the device in
any order or in parallel. The first one that succeeds in supplying any order or in parallel. The first one that succeeds in supplying
location can be used. location can be used.
AN-13/INT-15 Access networks that support more than one LCP MUST AN-13/INT-16 Access networks that support more than one LCP MUST
reply with the same location information (within the limits of the reply with the same location information (within the limits of the
data format for the specific LCP) for all LCPs it supports. data format for the specific LCP) for all LCPs it supports.
ED-??/INT-??/SP-?? When HELD is the LCP, the request MUST specify a ED-23/INT-17/SP-14 When HELD is the LCP, the request MUST specify a
value of "emergencyRouting" for the "responseTime" parameter and use value of "emergencyRouting" for the "responseTime" parameter and use
the resulting location for routing. If a value for dispatch location the resulting location for routing. If a value for dispatch location
will be sent, another request with the "responseTime" parameter set will be sent, another request with the "responseTime" parameter set
to "emergencyDispatch" must be completed, with the result sent for to "emergencyDispatch" must be completed, with the result sent for
dispatch purposes. dispatch purposes.
ED-?? Where the operating system supporting application programs ED-24 Where the operating system supporting application programs
which need location for emergency calls does not allow access to which need location for emergency calls does not allow access to
Layer 2 and Layer 3 functions necessary for a client application to Layer 2 and Layer 3 functions necessary for a client application to
use DHCP location options and/or LLDP-MED, the operating system MUST use DHCP location options and/or LLDP-MED, the operating system MUST
provide a published API conforming to ED-12 through ED-18 and ED-21 provide a published API conforming to ED-12 through ED-21 and ED-21
through ED-27. It is RECOMMENDED that all operating systems provide through ED-31. It is RECOMMENDED that all operating systems provide
such an API. such an API.
6.6. When location should be configured 6.6. When location should be configured
ED-23/INT-16 Endpoints SHOULD obtain location immediately after ED-25/INT-18 Endpoints SHOULD obtain location immediately after
obtaining local network configuration information.When HELD is the obtaining local network configuration information.When HELD is the
LCP the client MUST support a random back-off period (between 30 LCP the client MUST support a random back-off period (between 30
seconds and 300 seconds) for re-trying the HELD query, when no seconds and 300 seconds) for re-trying the HELD query, when no
response is received. response is received.
ED-??/INT-?? If the device is configured to use DHCP for ED-26/INT-19 If the device is configured to use DHCP for
bootstrapping, it MUST include both options for location acquisition bootstrapping, it MUST include both options for location acquisition
(civic and geodetic), the option for LIS discovery, and the option (civic and geodetic), the option for LIS discovery, and the option
for LoST discovery as defined in [RFC4676], [RFC3825], for LoST discovery as defined in [RFC4676], [RFC3825],
[I-D.thomson-geopriv-lis-discovery] and [I-D.thomson-geopriv-lis-discovery] and
[I-D.ietf-ecrit-dhc-lost-discovery]. [I-D.ietf-ecrit-dhc-lost-discovery].
ED-??/INT-?? If the device sends a DHCP INFORM message, it MUST ED-27/INT-20 If the device sends a DHCP INFORM message, it MUST
include both options for location acquisition (civic and geodetic), include both options for location acquisition (civic and geodetic),
the option for LIS discovery, and the option for LoST discovery as the option for LIS discovery, and the option for LoST discovery as
defined in [RFC4676], [RFC3825], [I-D.thomson-geopriv-lis-discovery] defined in [RFC4676], [RFC3825], [I-D.thomson-geopriv-lis-discovery]
and [I-D.ietf-ecrit-dhc-lost-discovery]. and [I-D.ietf-ecrit-dhc-lost-discovery].
ED-24/INT-16 To minimize the effects of VPNs that do not allow split ED-28/INT-21 To minimize the effects of VPNs that do not allow split
tunneling VPNs, location configuration SHOULD be attempted before tunneling VPNs, location configuration SHOULD be attempted before
such tunnels are established. such tunnels are established.
ED-25/INT-17 Software which uses LCPs SHOULD locate and use the ED-29/INT-22 Software which uses LCPs SHOULD locate and use the
actual hardware network interface rather than a VPN tunnel interface actual hardware network interface rather than a VPN tunnel interface
to direct LCP requests to the LIS in the actual access network. to direct LCP requests to the LIS in the actual access network.
AN-14 Network administrators MUST take care in assigning IP addresses AN-14 Network administrators MUST take care in assigning IP addresses
such that VPN address assignments can be distinguished from local such that VPN address assignments can be distinguished from local
devices (by subnet choice, for example), and LISs SHOULD NOT attempt devices (by subnet choice, for example), and LISs SHOULD NOT attempt
to provide location to addresses that arrive via VPN connections to provide location to addresses that arrive via VPN connections
unless it can accurately determine the location for such addresses. unless it can accurately determine the location for such addresses.
AN-15 Placement of NAT devices SHOULD consider the effect of the NAT AN-15 Placement of NAT devices where an LCP uses IP address for an
on the LCP. identifier SHOULD consider the effect of the NAT on the LCP. The
address used to query the LIS MUST be able to correctly identify the
record in the LIS representing the location of the querying device
ED-26/INT-18 For devices which are not expected to roam, refreshing ED-30/INT-23 For devices which are not expected to roam, refreshing
location on the order of once per day is RECOMMENDED. location on the order of once per day is RECOMMENDED.
ED-27/INT-19 For devices which roam, refresh of location information ED-31/INT-24 For devices which roam, refresh of location information
SHOULD be more frequent, with the frequency related to the mobility SHOULD be more frequent, with the frequency related to the mobility
of the device and the ability of the access network to support the of the device and the ability of the access network to support the
refresh operation. If the device can detect that it has moved, for refresh operation. If the device can detect that it has moved, for
example when it changes access points, the device SHOULD refresh its example when it changes access points, the device SHOULD refresh its
location. location.
ED-28/INT-20/AN-16 It is RECOMMENDED that location determination not ED-32/INT-25/AN-16 It is RECOMMENDED that location determination not
take longer than 250 ms to obtain routing location and systems SHOULD take longer than 250 ms to obtain routing location and systems SHOULD
be designed such that the typical response is under 100 ms. However, be designed such that the typical response is under 100 ms. However,
as much as 3 seconds to obtain routing location MAY be tolerated if as much as 3 seconds to obtain routing location MAY be tolerated if
location accuracy can be substantially improved over what can be location accuracy can be substantially improved over what can be
obtained in 250 ms. obtained in 250 ms.
6.7. Conveying location in SIP 6.7. Conveying location in SIP
ED-29/SP-14 Location sent between SIP elements MUST be conveyed using ED-33/SP-15 Location sent between SIP elements MUST be conveyed using
[I-D.ietf-sip-location-conveyance]. [I-D.ietf-sip-location-conveyance].
6.8. Location updates 6.8. Location updates
ED-30/AN-17 Where the absolute location or the accuracy of location ED-34/AN-17 Where the absolute location or the accuracy of location
of the endpoint may change between the time the call is received at of the endpoint may change between the time the call is received at
the PSAP and the time dispatch is completed, location update the PSAP and the time dispatch is completed, location update
mechanisms MUST be provided. mechanisms MUST be provided.
ED-31/AN-18 Mobile devices MUST be provided with a mechanism to get ED-35/AN-18 Mobile devices MUST be provided with a mechanism to get
repeated location updates to track the motion of the device during repeated location updates to track the motion of the device during
the complete processing of the call. the complete processing of the call.
ED-32/AN-19 The LIS SHOULD provide a location reference which permits ED-36/AN-19 The LIS SHOULD provide a location reference which permits
a subscription with appropriate filtering. a subscription with appropriate filtering.
ED-33/AN-20 For calls sent with location-by-reference, with a SIP or ED-37/AN-20 For calls sent with location-by-reference, with a SIP or
SIPS scheme, the server resolving the reference MUST support a SIPS scheme, the server resolving the reference MUST support a
SUBSCRIBE [RFC3118] to the presence event [RFC3856]. For other SUBSCRIBE [RFC3265] to the presence event [RFC3856]. For other
location-by-reference schemes, the PSAP will have to repeatedly location-by-reference schemes, the PSAP will have to repeatedly
dereference the URI to determine if the device moved. dereference the URI to determine if the device moved.
ED-34 If location was sent by value, and the endpoint gets updated ED-38 If location was sent by value, and the endpoint gets updated
location, it MUST send the updated location to the PSAP via a SIP re- location, it MUST send the updated location to the PSAP via a SIP re-
INVITE or UPDATE request. Such updates SHOULD be limited to no more INVITE or UPDATE request. Such updates SHOULD be limited to no more
than one update every 10 seconds. than one update every 10 seconds.
6.9. Multiple locations 6.9. Multiple locations
ED-35 If a UA has more than one location available to it, it MUST ED-39 If a UA has more than one location available to it, it MUST
choose one location to route the call towards the PSAP. choose one location to route the call towards the PSAP.
SP-15 If a proxy inserts location on behalf of an endpoint, and it SP-16 If a proxy inserts location on behalf of an endpoint, and it
has multiple locations available for the endpoint it MUST choose one has multiple locations available for the endpoint it MUST choose one
location to use to route the call towards the PSAP. location to use to route the call towards the PSAP.
SP-16 If a proxy is attempting to insert location but the UA conveyed SP-17 If a proxy is attempting to insert location but the UA conveyed
a location to it, the proxy MUST use the UA's location for routing a location to it, the proxy MUST use the UA's location for routing
and MUST convey that location towards the PSAP. It MAY also include and MUST convey that location towards the PSAP. It MAY also include
what it believes the location to be in a separate Geolocation header. what it believes the location to be in a separate Geolocation header.
SP-17 All location objects received by a proxy MUST be delivered to SP-18 All location objects received by a proxy MUST be delivered to
the PSAP. the PSAP.
ED-36/SP-18 Location objects MUST contain information about the ED-40/SP-19 Location objects MUST contain information about the
method by which the location was determined, such as GPS, manually method by which the location was determined, such as GPS, manually
entered, or based on access network topology included in a PIDF- LO entered, or based on access network topology included in a PIDF- LO
"method" element. In addition, the source of the location "method" element. In addition, the source of the location
information MUST be included in a PIDF-LO "provided-by" element. information MUST be included in a PIDF-LO "provided-by" element.
ED-37/SP-19 The "used-for-routing" parameter MUST be set to the ED-41/SP-20 The "used-for-routing" parameter MUST be set to the
location that was used to query LoST. location that was used to query LoST.
6.10. Location validation 6.10. Location validation
AN-21 A LIS should perform location validation of civic locations via AN-21 A LIS should perform location validation of civic locations via
LoST before entering a location in its database. LoST before entering a location in its database.
ED-38 Endpoints SHOULD validate civic locations when they receive ED-42 Endpoints SHOULD validate civic locations when they receive
them from their LCP. Validation SHOULD be performed in conjunction them from their LCP. Validation SHOULD be performed in conjunction
with the LoST route query to minimize load on the LoST server. with the LoST route query to minimize load on the LoST server.
6.11. Default location 6.11. Default location
AN-22 When the access network cannot determine the actual location of AN-22 When the access network cannot determine the actual location of
the caller, it MUST supply a default location. The default SHOULD be the caller, it MUST supply a default location. The default SHOULD be
chosen to be as close to the probable location of the device as the chosen to be as close to the probable location of the device as the
network can determine. See [I-D.ietf-ecrit-framework] network can determine. See [I-D.ietf-ecrit-framework]
SP-20 Proxies handling emergency calls MUST insert a default location SP-21 Proxies handling emergency calls MUST insert a default location
if the call does not contain a location and the proxy does not have a if the call does not contain a location and the proxy does not have a
method for obtaining a better location. method for obtaining a better location.
AN-23/SP-21 Default locations MUST be marked with method=Default and AN-23/SP-22 Default locations MUST be marked with method=Default and
an appropriate provided-by in the PIDF-LO. the proxy MUST be identfied in provided-by element of the PIDF-LO.
6.12. Other location considerations 6.12. Other location considerations
ED-39 If the LCP does not return location in the form of a PIDF-LO ED-43 If the LCP does not return location in the form of a PIDF-LO
[RFC4119], the endpoint MUST map the location information it receives [RFC4119], the endpoint MUST map the location information it receives
from the configuration protocol to a PIDF-LO. from the configuration protocol to a PIDF-LO.
ED-40/AN-24 To prevent against spoofing of the DHCP server, elements ED-44/AN-24 To prevent against spoofing of the DHCP server, elements
implementing DHCP for location configuration SHOULD use [RFC3118]. implementing DHCP for location configuration SHOULD use although the
difficulty in providing appropriate credentials is significant.
[RFC3118].
ED-41 S/MIME MUST NOT be used to encrypt the SIP Geolocation header ED-45 S/MIME MUST NOT be used to encrypt the SIP Geolocation header
or bodies. or bodies.
ED-42/SP-22 TLS MUST be used to protect location (but see ED-46/SP-23 TLS MUST be used to protect location (but see
Section 9.1). IPSEC [RFC2401] is an acceptable alternative. Section 9.1). IPSEC [RFC2401] is an acceptable alternative.
6.13. LIS and LoST Discovery 7. LIS and LoST Discovery
ED-xx Endpoints MUST support one or more mechanisms that allow them ED-47 Endpoints MUST support one or more mechanisms that allow them
to determine their public IP address. Examples include ICE to determine their public IP address. Examples include ICE
[I-D.ietf-mmusic-ice] and HTTP get. [I-D.ietf-mmusic-ice] and HTTP get.
ED-xx Endpoints MUST support LIS discovery as described in ED-48 Endpoints MUST support LIS discovery as described in
[I-D.thomson-geopriv-lis-discovery], and the LoST discovery as [I-D.thomson-geopriv-lis-discovery], and the LoST discovery as
described in [I-D.ietf-ecrit-dhc-lost-discovery]. described in [I-D.ietf-ecrit-dhc-lost-discovery].
ED-xx The device MUST have a configurable default LoST server ED-49 The device MUST have a configurable default LoST server
parameter. If the device is provided by or managed by service parameter. If the device is provided by or managed by service
provider, it is expected that the service provider will configure provider, it is expected that the service provider will configure
this option. this option.
7. Uninitialized devices
ED-43 Uninitialized devices SHOULD NOT lead a user to believe an
emergency call could be placed on it unless local regulations require
it.
ED-44/AN-25/SP-23 Uninitialized devices SHOULD NOT be capable of
placing an emergency call unless local regulations require it.
ED-45/AN-26/SP-24 Uninitialized devices that can place emergency
calls MUST supply location the same as a fully capable device would.
ED-46/SP-25 Unitialized devices MUST supply a call back URI. See
Section 7.
ED-47/SP-26 Unitialized devices MUST include identifiers in the
signaling that can be used by the service provider to identify the
device and to allow filtering of calls from the device by the PSAP/
ESRP.
8. Routing the call to the PSAP 8. Routing the call to the PSAP
ED-48 Endpoints who obtain their own location SHOULD perform LoST ED-50 Endpoints who obtain their own location SHOULD perform LoST
mapping to the PSAP URI. mapping to the PSAP URI.
ED-49 Mapping SHOULD be performed at boot time and whenever location ED-51 Mapping SHOULD be performed at boot time and whenever location
changes beyond the service boundary obtained from a prior LoST changes beyond the service boundary obtained from a prior LoST
mapping operation or the time-to-live value of that response has mapping operation or the time-to-live value of that response has
expired. The value MUST be cached for possible later use. expired. The value MUST be cached for possible later use.
ED-50 The endpoint MUST attempt to update its location at the time of ED-52 The endpoint MUST attempt to update its location at the time of
an emergency call. If it cannot obtain a new location quickly (see an emergency call. If it cannot obtain a new location quickly (see
Section 6), it MUST use the cached value. Section 6), it MUST use the cached value.
ED-51 The endpoint SHOULD attempt to update the LoST mapping at the ED-53 The endpoint SHOULD attempt to update the LoST mapping at the
time of an emergency call. If it cannot obtain a new mapping time of an emergency call. If it cannot obtain a new mapping
quickly, it MUST use the cached value. quickly, it MUST use the cached value if it has one.
SP-27 All proxies in the outbound path SHOULD recognize emergency SP-24 Networks MUST be designed so that at least one proxy in the
calls with a Request URI of the service URN in the "sos" tree. An outbound path can recognize emergency calls with a Request URI of the
endpoint places a service URN in the Request URI to indicate that the service URN in the "sos" tree. An endpoint places a service URN in
endpoint understood the call was an emergency call. A proxy that the Request URI to indicate that the endpoint understood the call was
processes such a call looks for the presence of a SIP Route header an emergency call. A proxy that processes such a call looks for the
field with a URI of a PSAP. Absence of such a Route header indicates presence of a SIP Route header field with a URI of a PSAP. Absence
the UAC was unable to invoke LoST and the proxy MUST perform the LoST of such a Route header indicates the UAC was unable to invoke LoST
mapping and insert a Route header field with the URI obtained. and the proxy MUST perform the LoST mapping and insert a Route header
field with the URI obtained.
SP-28 To deal with old user agents that predate this specification SP-25 To deal with old user agents that predate this specification
and with UAs that do not have access to their own location data, a and with UAs that do not have access to their own location data, a
proxy that recognizes a call as an emergency call that is not marked proxy that recognizes a call as an emergency call that is not marked
as such (see Section 5) MUST also perform this mapping, with the best as such (see Section 5) MUST also perform this mapping, with the best
location it has available for the endpoint. The resulting PSAP URI location it has available for the endpoint. The resulting PSAP URI
would be placed in a Route header with the service URN in the Request would be placed in a Route header with the service URN in the Request
URI. URI.
SP-29 Proxy servers performing mapping SHOULD use location obtained SP-26 Proxy servers performing mapping SHOULD use location obtained
from the access network for the mapping. If no location is from the access network for the mapping. If no location is
available, a default location (see Section 6.11) MUST be supplied. available, a default location (see Section 6.11) MUST be supplied.
SP-30 A proxy server which attempts mapping and fails to get a SP-27 A proxy server which attempts mapping and fails to get a
mapping MUST provide a default mapping. A suitable default mapping mapping MUST provide a default mapping. A suitable default mapping
would be the mapping obtained previously for the default location would be the mapping obtained previously for the default location
appropriate for the caller. appropriate for the caller.
ED-52/SP-31 [RFC3261] and [RFC3263] procedures MUST be used to route ED-54/SP-28 [RFC3261] and [RFC3263] procedures MUST be used to route
an emergency call towards the PSAP's URI. an emergency call towards the PSAP's URI.
ED-53 Initial INVITES MUST provide an Offer [RFC3264]. ED-55 Initial INVITES MUST provide an Offer [RFC3264].
9. Signaling of emergency calls 9. Signaling of emergency calls
ED-54 Best Current Practice for SIP user agents [RFC4504] including ED-56 Best Current Practice for SIP user agents [RFC4504] including
handling of audio, video and real-time text [RFC4103] MUST be handling of audio, video and real-time text [RFC4103] SHOULD be
applied. This memo can be considered as an addition to [RFC4504] for applied. This memo can be considered as an addition to [RFC4504] for
endpoints. endpoints.
9.1. Use of TLS 9.1. Use of TLS
ED-55/SP-32 TLS MUST be specified when attempting to signal an ED-57/SP-29 TLS MUST be specified when attempting to signal an
emergency call with SIP per [I-D.ietf-sip-sips]. IPSEC [RFC2401] is emergency call with SIP per [I-D.ietf-sip-sips]. IPSEC [RFC2401] is
an acceptable alternative. an acceptable alternative.
ED-56/SP-33 If TLS session establishment fails, the call MUST be ED-58/SP-30 If TLS session establishment fails, the call MUST be
retried without TLS. retried without TLS.
ED-57/SP-34 [I-D.ietf-sip-outbound] is RECOMMENDED to maintain ED-59/SP-31 [I-D.ietf-sip-outbound] is RECOMMENDED to maintain
persistent TLS connections between elements. persistent TLS connections between elements.
ED-58/AN-27 TLS MUST be specified when attempting to retrieve ED-60/AN-25 TLS MUST be specified when attempting to retrieve
location (configuration or dereferencing) with HELD. The use of location (configuration or dereferencing) with HELD. The use of
[RFC4507] is RECOMMENDED to minimise the time to establish TLS [RFC4507] is RECOMMENDED to minimise the time to establish TLS
sessions. sessions.
ED-59/AN33 If TLS session establishment fails, the location ED-61/AN-26 If TLS session establishment fails, the location
retrieveal MUST be retried without TLS. retrieveal MUST be retried without TLS.
9.2. SIP signaling requirements for User Agents 9.2. SIP signaling requirements for User Agents
ED-60 The initial SIP signaling method is an INVITE request: ED-62 The initial SIP signaling method is an INVITE request:
1. The Request URI SHOULD be the service URN in the "sos" tree, If 1. The Request URI SHOULD be the service URN in the "sos" tree, If
the device cannot interpert local dial strings, the Request-URI the device cannot interpert local dial strings, the Request-URI
SHOULD be a dial string URI [RFC4967] with the dialed digits. SHOULD be a dial string URI [RFC4967] with the dialed digits.
2. The To header SHOULD be a service URN in the "sos" tree. If the 2. The To header SHOULD be a service URN in the "sos" tree. If the
device cannot do interpret local dial strings, the To: SHOULD be device cannot do interpret local dial strings, the To: SHOULD be
a dial string URI with the dialed digits. a dial string URI with the dialed digits.
3. The From header MUST be present and SHOULD be the AoR of the 3. The From header MUST be present and SHOULD be the AoR of the
caller. caller.
4. A Via header MUST be present and SHOULD include the URI of the 4. A Via header MUST be present.
device.
5. A Route header SHOULD be present with a PSAP URI obtained from 5. A Route header SHOULD be present with a PSAP URI obtained from
LoST (see Section 8) and the loose route parameter. If the LoST (see Section 8) and the loose route parameter. If the
device does not interpet dial plans, no Route header will be device does not interpet dial plans, or was unable to obtain a
present. route from a LoST serverr, no Route header will be present.
6. A Contact header MUST be present which MUST be globally 6. A Contact header MUST be present which MUST be globally
routable, for example a GRUU [I-D.ietf-sip-gruu], to permit an routable, for example a GRUU [I-D.ietf-sip-gruu], to permit an
immediate call-back to the specific device which placed the immediate call-back to the specific device which placed the
emergency call. emergency call.
7. Other headers MAY be included as per normal SIP behavior. 7. Other headers MAY be included as per normal SIP behavior.
8. A Supported header MUST be included with the 'geolocation' 8. A Supported header MUST be included with the 'geolocation'
option tag [I-D.ietf-sip-location-conveyance], unless the device option tag [I-D.ietf-sip-location-conveyance], unless the device
does not understand the concept of SIP location. does not understand the concept of SIP location.
9. If a device understands the SIP location conveyance 9. If a device understands the SIP location conveyance
[I-D.ietf-sip-location-conveyance] extension and has its [I-D.ietf-sip-location-conveyance] extension and has its
location available, it MUST include location either by-value or location available, it MUST include location either by-value,
by-reference. by-reference or both.
10. If a device understands the SIP Location Conveyance extension 10. If a device understands the SIP Location Conveyance extension
and has its location unavailable or unknown to that device, it and has its location unavailable or unknown to that device, it
MUST include a Supported header with a "geolocation" option tag, MUST include a Supported header with a "geolocation" option tag,
and MUST NOT include a Geolocation header, and not include a and MUST NOT include a Geolocation header, and not include a
PIDF-LO message body. PIDF-LO message body.
11. If a device understands the SIP Location Conveyance extension 11. If a device understands the SIP Location Conveyance extension
and supports LoST [I-D.ietf-ecrit-lost], the Geolocation "used- and supports LoST [I-D.ietf-ecrit-lost], the Geolocation "used-
for-routing" header parameter MUST be added to the corresponding for-routing" header parameter MUST be added to the corresponding
URI in the Geolocation header. URI in the Geolocation header.
12. A normal SDP offer SHOULD be included in the INVITE. If voice 12. A normal SDP offer SHOULD be included in the INVITE. If voice
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15. SIP Caller Preferences [RFC3841] MAY be used to signal how the 15. SIP Caller Preferences [RFC3841] MAY be used to signal how the
PSAP should handle the call. For example, a language preference PSAP should handle the call. For example, a language preference
expressed in an Accept-Language header may be used as a hint to expressed in an Accept-Language header may be used as a hint to
cause the PSAP to route the call to a call taker who speaks the cause the PSAP to route the call to a call taker who speaks the
requested language. SIP Caller Preferences may also be used to requested language. SIP Caller Preferences may also be used to
indicate a need to invoke a relay service for communication with indicate a need to invoke a relay service for communication with
people with disabilities in the call. people with disabilities in the call.
9.3. SIP signaling requirements for proxy servers 9.3. SIP signaling requirements for proxy servers
SP-35 SIP Proxy servers processing emergency calls: SP-32 SIP Proxy servers processing emergency calls:
1. If the proxy does interprets dial plans on behalf of user agents, 1. If the proxy does interprets dial plans on behalf of user agents,
the proxy MUST look for the local emergency dial string at the the proxy MUST look for the local emergency dial string at the
location of the end device and MAY look for the home dial string. location of the end device and MAY look for the home dial string.
If it finds it, the proxy MUST: If it finds it, the proxy MUST:
* Insert a Geolocation header as above. Location-by-reference * Insert a Geolocation header as above. Location-by-reference
MUST be used because proxies must not insert bodies. MUST be used because proxies must not insert bodies.
* Include the Geolocation "inserted-by=server" and "used-for- * Include the Geolocation "inserted-by=server" and "used-for-
routing" parameters. routing" parameters.
* Map the location to a PSAP URI using LoST. * Map the location to a PSAP URI using LoST.
* Add a Route header with the PSAP URI. * Add a Route header with the PSAP URI.
skipping to change at page 16, line 16 skipping to change at page 15, line 45
on the call MUST NOT be modified or deleted in transit. on the call MUST NOT be modified or deleted in transit.
4. The proxy SHOULD NOT modify any parameters in Geolocation headers 4. The proxy SHOULD NOT modify any parameters in Geolocation headers
received in the call. It MAY add a Geolocation header. Such an received in the call. It MAY add a Geolocation header. Such an
additional location SHOULD NOT be used for routing; the location additional location SHOULD NOT be used for routing; the location
provided by the UA should be used. provided by the UA should be used.
5. Either a P-Asserted-Identity [RFC3325] or an Identity header 5. Either a P-Asserted-Identity [RFC3325] or an Identity header
[RFC4474], or both, MUST be included to identify the sender. [RFC4474], or both, MUST be included to identify the sender.
10. Call backs 10. Call backs
SP-36 Unitialized devices, like any device MUST have a globally SP-33 Unitialized devices, like any device MUST have a globally
routable URI in a Contact: header. routable URI in a Contact: header.
SP-37 Unitialized devices SHOULD have a persistent URI in a SP-34 Unitialized devices SHOULD have a persistent URI in a
P-Asserted-Identity: header if there is some way to assign such an P-Asserted-Identity: header if there is some way to assign such an
identifier to the device. identifier to the device.
11. Mid-call behavior 11. Mid-call behavior
ED-61/SP-38 During the course of an emergency call, devices and ED-63/SP-35 During the course of an emergency call, devices and
proxies MUST support REFER transactions and the Referred-by: header proxies MUST support REFER transactions and the Referred-by: header
[RFC3515]. [RFC3515].
ED-62/SP-39 User agents and proxies MUST support Session Timer ED-64/SP-36 User agents and proxies MUST support Session Timer
[RFC4028] to guard against session corruption. [RFC4028] to guard against session corruption.
12. Call termination 12. Call termination
ED-63 UACs with an active emergency call (i.e. SIP Dialog) MUST NOT ED-65 UACs with an active emergency call (i.e. SIP Dialog) MUST NOT
generate a BYE request (or equivalent for other non-SIP signaling). generate a BYE request (or equivalent for other non-SIP signaling).
The PSAP must be the only entity that can terminate a call. If the The PSAP must be the only entity that can terminate a call. If the
user "hangs up" an emergency call, the device should alert the user, user "hangs up" an emergency call, the device should alert the user,
and when answered, reconnect the caller to the PSAP. and if the user responds by attempting to pick up the call, the
device MUST reconnect the caller to the PSAP.
ED-64 There can be a case where the session signaling path is lost, ED-66 There can be a case where the session signaling path is lost,
and the user agent does not receive the BYE. If the call is hung up, and the user agent does not receive the BYE. If the call is hung up,
and the session timer expires the call MAY be declared lost. If in and the session timer (if implemented) expires, the call MAY be
the interval, an incoming call is received from the domain of the declared lost. If in the interval, an incoming call is received from
PSAP, the device SHOULD drop the old call and alert for the (new) the domain of the PSAP, the device MUST drop the old call and alert
incoming call. Dropping of the old call SHOULD only occur if the for the (new) incoming call. Dropping of the old call MUST only
user is attempting to hang up; the domain of an incoming call can occur if the user is attempting to hang up; the domain of an incoming
only be determined from the From header, which is not reliable, and call can only be determined from the From header, which is not
could be spoofed. Dropping an active call by a new call with a reliable, and could be spoofed. Dropping an active call by a new
spoofed From: would be a DoS attack. call with a spoofed From: would be a DoS attack.
13. Disabling of features 13. Disabling of features
ED-65/SP-40 User Agents and proxys MUST disable outgoing call ED-67/SP-37 User Agents and proxys MUST disable outgoing call
features such as features such as
o Call Waiting o Call Waiting
o Call Transfer o Call Transfer
o Three Way Call o Three Way Call
o Flash hold o Flash hold
o Outbound Call Blocking o Outbound Call Blocking
when an emergency call is established. Also see ED-72 in Section 14. when an emergency call is established. Also see ED-72 in Section 14.
ED-66/SP-41 The emergency dialstrings SHOULD NOT be permitted in Call ED-68/SP-38 The emergency dialstrings SHOULD NOT be permitted in Call
Forward numbers or speed dial lists. Forward numbers or speed dial lists.
ED-67/SP-42 The User Agent and Proxies SHOULD disable the following ED-69/SP-39 The User Agent and Proxies SHOULD disable the following
incoming call features on call backs from the PSAP: incoming call features on call backs from the PSAP:
o Call Waiting o Call Waiting
o Do Not Disturb o Do Not Disturb
o Call Forward (all kinds) o Call Forward (all kinds)
ED-68 Call backs SHOULD be determined by retaining the domain of the ED-70 Call backs SHOULD be determined by retaining the domain of the
PSAP which answers an outgoing emergency call and instantiating a PSAP which answers an outgoing emergency call and instantiating a
timer which starts when the call is terminated. If a call is timer which starts when the call is terminated. If a call is
received from the same domain and within the timer period, sent to received from the same domain and within the timer period, sent to
the Contact: or AoR used in the emergency call, it should be assumed the Contact: or AoR used in the emergency call, it should be assumed
to be a call back. The suggested timer period is 5 minutes. to be a call back. The suggested timer period is 5 minutes.
14. Media 14. Media
ED-69 Endpoints MUST send and receive media streams on RTP [RFC3550]. ED-71 Endpoints MUST send and receive media streams on RTP [RFC3550].
ED-70 Normal SIP offer/answer [RFC3264] negotiations MUST be used to ED-72 Normal SIP offer/answer [RFC3264] negotiations MUST be used to
agree on the media streams to be used. agree on the media streams to be used.
ED-71 Endpoints supporting voice MUST support G.711 A law (and mu Law ED-73 Endpoints supporting voice MUST support G.711 A law (and mu Law
if they could be used in North America) encoded voice as described in if they could be used in North America) encoded voice as described in
[RFC3551]. It is desirable to include wideband codecs such as AMR-WB [RFC3551]. It is desirable to include wideband codecs such as AMR-WB
in the offer. in the offer.
ED-72 Silence suppression (Voice Activity Detection methods) MUST NOT ED-74 Silence suppression (Voice Activity Detection methods) MUST NOT
be used on emergency calls. PSAP call takers sometimes get be used on emergency calls. PSAP call takers sometimes get
information on what is happening in the background to determine how information on what is happening in the background to determine how
to process the call. to process the call.
ED-73 Endpoints supporting IM MUST support either [RFC3428] or ED-75 Endpoints supporting IM MUST support both [RFC3428] and
[RFC3920]. [RFC4975].
ED-74 Endpoints supporting real-time text MUST use [RFC4103]. The ED-76 Endpoints supporting real-time text MUST use [RFC4103]. The
expectations for emergency service support for the real-time text expectations for emergency service support for the real-time text
medium, described in [I-D.ietf-sipping-toip], Section 7.1 SHOULD be medium, described in [I-D.ietf-sipping-toip], Section 7.1 SHOULD be
fulfilled. fulfilled.
ED-75 Endpoints supporting video MUST support H.264 per [RFC3984]. ED-77 Endpoints supporting video MUST support H.264 per [RFC3984].
15. Testing 15. Testing
ED-76 INVITE requests to a service URN with a urn parameter of "test" ED-78 INVITE requests to a service URN ending in ".test" indicates a
indicates a request for an automated test. For example, request for an automated test. For example,
"urn:service.sos.fire;test". As in standard SIP, a 200 (OK) response "urn:service.sos.fire.test". As in standard SIP, a 200 (OK) response
indicates that the address was recognized and a 404 (Not found) that indicates that the address was recognized and a 404 (Not found) that
it was not. A 486 (Busy Here) MUST be returned if the test service it was not. A 486 (Busy Here) MUST be returned if the test service
is busy, and a 488 (Not Acceptable Here) MUST be returned if the PSAP is busy, and a 488 (Not Acceptable Here) MUST be returned if the PSAP
does not support the test mechanism. does not support the test mechanism.
ED-77 In its response to the test, the PSAP MAY include a text body ED-79 In its response to the test, the PSAP MAY include a text body
(text/plain) indicating the identity of the PSAP, the requested (text/plain) indicating the identity of the PSAP, the requested
service, and the location reported with the call. For the latter, service, and the location reported with the call. For the latter,
the PSAP SHOULD return location-by-value even if the original the PSAP SHOULD return location-by-value even if the original
location delivered with the test was by-reference. If the location- location delivered with the test was by-reference. If the location-
by-reference was supplied, and the dereference requires credentials, by-reference was supplied, and the dereference requires credentials,
the PSAP SHOULD use credentials supplied by the LIS for test the PSAP SHOULD use credentials supplied by the LIS for test
purposes. This alerts the LIS that the dereference is not for an purposes. This alerts the LIS that the dereference is not for an
actual emergency call and location hiding techniques, if they are actual emergency call and location hiding techniques, if they are
being used, may be employed for this dereference. The response MAY being used, may be employed for this dereference. The response MAY
include the connected identity of the PSAP per include the connected identity of the PSAP per
[I-D.ietf-sip-connected-identity]. [I-D.ietf-sip-connected-identity].
ED-78 A PSAP accepting a test call SHOULD accept a media loopback ED-80 A PSAP accepting a test call SHOULD accept a media loopback
test [I-D.ietf-mmusic-media-loopback] and SHOULD support the "rtp- test [I-D.ietf-mmusic-media-loopback] and SHOULD support the "rtp-
pkt-loopback" and "rtp-start-loopback" options. The user agent would pkt-loopback" and "rtp-start-loopback" options. The user agent would
specify a loopback attribute of "loopback-source", the PSAP being the specify a loopback attribute of "loopback-source", the PSAP being the
mirror. User Agents should expect the PSAP to loop back no more than mirror. User Agents should expect the PSAP to loop back no more than
3 packets of each media type accepted (which limits the duration of 3 packets of each media type accepted (which limits the duration of
the test), after which the PSAP would normally send BYE. the test), after which the PSAP would normally send BYE.
ED-79 User agents SHOULD perform a full call test, including media ED-81 User agents SHOULD perform a full call test, including media
loopback, after a disconnect and subsequent change in IP address not loopback, after a disconnect and subsequent change in IP address not
due to a reboot. After an initial test, a full test SHOULD be due to a reboot. After an initial test, a full test SHOULD be
repeated approximately every 30 days with a random interval. repeated approximately every 30 days with a random interval.
ED-80 User agents MUST NOT place a test call immediately after ED-82 User agents MUST NOT place a test call immediately after
booting. If the IP address changes after booting, the UA should wait booting. If the IP address changes after booting, the UA should wait
a random amount of time (in perhaps a 30 minute period, sufficient a random amount of time (in perhaps a 30 minute period, sufficient
for any avalanche restart to complete) and then test. for any avalanche restart to complete) and then test.
ED-81 PSAPs MAY refuse repeated requests for test from the same ED-83 PSAPs MAY refuse repeated requests for test from the same
device in a short period of time. Any refusal is signaled with a 486 device in a short period of time. Any refusal is signaled with a 486
or 488 response. or 488 response.
16. Security Considerations 16. Security Considerations
Security considerations for emergency calling have been documented in Security considerations for emergency calling have been documented in
[I-D.ietf-ecrit-security-threats], and [I-D.barnes-geopriv-lo-sec]. [I-D.ietf-ecrit-security-threats], and [I-D.barnes-geopriv-lo-sec].
17. Acknowledgements 17. Acknowledgements
Work group members participating in the creation and review of this Work group members participating in the creation and review of this
document include include Hannes Tschofenig, Ted Hardie, Marc Linsner, document include include Hannes Tschofenig, Ted Hardie, Marc Linsner,
Roger Marshall, Stu Goldman, Shida Schubert, James Winterbottom, Roger Marshall, Stu Goldman, Shida Schubert, James Winterbottom,
Barbara Stark, Richard Barnes and Peter Blatherwick. Barbara Stark, Richard Barnes and Peter Blatherwick.
18. Normative References 18. Normative References
[I-D.barnes-geopriv-lo-sec] [I-D.barnes-geopriv-lo-sec]
Barnes, R., "Threats to GEOPRIV Location Objects", Barnes, R., Lepinski, M., Tschofenig, H., and H.
draft-barnes-geopriv-lo-sec-00 (work in progress), Schulzrinne, "Security Requirements for the Geopriv
July 2007. Location System", draft-barnes-geopriv-lo-sec-02 (work in
progress), February 2008.
[I-D.ietf-ecrit-dhc-lost-discovery] [I-D.ietf-ecrit-dhc-lost-discovery]
Schulzrinne, H., "A Dynamic Host Configuration Protocol Schulzrinne, H., "A Dynamic Host Configuration Protocol
(DHCP) based Location-to-Service Translation Protocol (DHCP) based Location-to-Service Translation Protocol
(LoST) Discovery Procedure", (LoST) Discovery Procedure",
draft-ietf-ecrit-dhc-lost-discovery-02 (work in progress), draft-ietf-ecrit-dhc-lost-discovery-02 (work in progress),
July 2007. July 2007.
[I-D.ietf-ecrit-framework] [I-D.ietf-ecrit-framework]
Rosen, B., Schulzrinne, H., Polk, J., and A. Newton, Rosen, B., Schulzrinne, H., Polk, J., and A. Newton,
"Framework for Emergency Calling using Internet "Framework for Emergency Calling using Internet
Multimedia", draft-ietf-ecrit-framework-03 (work in Multimedia", draft-ietf-ecrit-framework-04 (work in
progress), September 2007. progress), November 2007.
[I-D.ietf-ecrit-lost] [I-D.ietf-ecrit-lost]
Hardie, T., "LoST: A Location-to-Service Translation Hardie, T., Newton, A., Schulzrinne, H., and H.
Protocol", draft-ietf-ecrit-lost-06 (work in progress), Tschofenig, "LoST: A Location-to-Service Translation
August 2007. Protocol", draft-ietf-ecrit-lost-07 (work in progress),
February 2008.
[I-D.ietf-ecrit-requirements] [I-D.ietf-ecrit-requirements]
Schulzrinne, H. and R. Marshall, "Requirements for Schulzrinne, H. and R. Marshall, "Requirements for
Emergency Context Resolution with Internet Technologies", Emergency Context Resolution with Internet Technologies",
draft-ietf-ecrit-requirements-13 (work in progress), draft-ietf-ecrit-requirements-13 (work in progress),
March 2007. March 2007.
[I-D.ietf-ecrit-security-threats] [I-D.ietf-ecrit-security-threats]
Taylor, T., "Security Threats and Requirements for Taylor, T., "Security Threats and Requirements for
Emergency Call Marking and Mapping", Emergency Call Marking and Mapping",
skipping to change at page 20, line 21 skipping to change at page 20, line 8
[I-D.ietf-ecrit-service-urn] [I-D.ietf-ecrit-service-urn]
Schulzrinne, H., "A Uniform Resource Name (URN) for Schulzrinne, H., "A Uniform Resource Name (URN) for
Emergency and Other Well-Known Services", Emergency and Other Well-Known Services",
draft-ietf-ecrit-service-urn-07 (work in progress), draft-ietf-ecrit-service-urn-07 (work in progress),
August 2007. August 2007.
[I-D.ietf-geopriv-http-location-delivery] [I-D.ietf-geopriv-http-location-delivery]
Barnes, M., Winterbottom, J., Thomson, M., and B. Stark, Barnes, M., Winterbottom, J., Thomson, M., and B. Stark,
"HTTP Enabled Location Delivery (HELD)", "HTTP Enabled Location Delivery (HELD)",
draft-ietf-geopriv-http-location-delivery-03 (work in draft-ietf-geopriv-http-location-delivery-05 (work in
progress), November 2007. progress), February 2008.
[I-D.ietf-geopriv-pdif-lo-profile] [I-D.ietf-geopriv-pdif-lo-profile]
Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV
PIDF-LO Usage Clarification, Considerations and PIDF-LO Usage Clarification, Considerations and
Recommendations", draft-ietf-geopriv-pdif-lo-profile-10 Recommendations", draft-ietf-geopriv-pdif-lo-profile-11
(work in progress), October 2007. (work in progress), February 2008.
[I-D.ietf-geopriv-revised-civic-lo]
Thomson, M. and J. Winterbottom, "Revised Civic Location
Format for PIDF-LO",
draft-ietf-geopriv-revised-civic-lo-06 (work in progress),
October 2007.
[I-D.ietf-mmusic-ice] [I-D.ietf-mmusic-ice]
Rosenberg, J., "Interactive Connectivity Establishment Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT) (ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", Traversal for Offer/Answer Protocols",
draft-ietf-mmusic-ice-19 (work in progress), October 2007. draft-ietf-mmusic-ice-19 (work in progress), October 2007.
[I-D.ietf-mmusic-media-loopback] [I-D.ietf-mmusic-media-loopback]
Hedayat, K., "An Extension to the Session Description Hedayat, K., "An Extension to the Session Description
Protocol (SDP) for Media Loopback", Protocol (SDP) for Media Loopback",
skipping to change at page 21, line 14 skipping to change at page 20, line 43
[I-D.ietf-sip-gruu] [I-D.ietf-sip-gruu]
Rosenberg, J., "Obtaining and Using Globally Routable User Rosenberg, J., "Obtaining and Using Globally Routable User
Agent (UA) URIs (GRUU) in the Session Initiation Protocol Agent (UA) URIs (GRUU) in the Session Initiation Protocol
(SIP)", draft-ietf-sip-gruu-15 (work in progress), (SIP)", draft-ietf-sip-gruu-15 (work in progress),
October 2007. October 2007.
[I-D.ietf-sip-location-conveyance] [I-D.ietf-sip-location-conveyance]
Polk, J. and B. Rosen, "Location Conveyance for the Polk, J. and B. Rosen, "Location Conveyance for the
Session Initiation Protocol", Session Initiation Protocol",
draft-ietf-sip-location-conveyance-08 (work in progress), draft-ietf-sip-location-conveyance-09 (work in progress),
July 2007. November 2007.
[I-D.ietf-sip-outbound] [I-D.ietf-sip-outbound]
Jennings, C. and R. Mahy, "Managing Client Initiated Jennings, C. and R. Mahy, "Managing Client Initiated
Connections in the Session Initiation Protocol (SIP)", Connections in the Session Initiation Protocol (SIP)",
draft-ietf-sip-outbound-10 (work in progress), July 2007. draft-ietf-sip-outbound-11 (work in progress),
November 2007.
[I-D.ietf-sip-sips] [I-D.ietf-sip-sips]
Audet, F., "The use of the SIPS URI Scheme in the Session Audet, F., "The use of the SIPS URI Scheme in the Session
Initiation Protocol (SIP)", draft-ietf-sip-sips-07 (work Initiation Protocol (SIP)", draft-ietf-sip-sips-08 (work
in progress), November 2007. in progress), February 2008.
[I-D.ietf-sipping-config-framework] [I-D.ietf-sipping-config-framework]
Channabasappa, S., "A Framework for Session Initiation Channabasappa, S., "A Framework for Session Initiation
Protocol User Agent Profile Delivery", Protocol User Agent Profile Delivery",
draft-ietf-sipping-config-framework-14 (work in progress), draft-ietf-sipping-config-framework-15 (work in progress),
November 2007. February 2008.
[I-D.ietf-sipping-toip] [I-D.ietf-sipping-toip]
Wijk, A. and G. Gybels, "Framework for real-time text over Wijk, A. and G. Gybels, "Framework for real-time text over
IP using the Session Initiation Protocol (SIP)", IP using the Session Initiation Protocol (SIP)",
draft-ietf-sipping-toip-08 (work in progress), draft-ietf-sipping-toip-08 (work in progress),
October 2007. October 2007.
[I-D.thomson-geopriv-lis-discovery] [I-D.thomson-geopriv-lis-discovery]
Thomson, M. and J. Winterbottom, "Discovering the Local Thomson, M. and J. Winterbottom, "Discovering the Local
Location Information Server (LIS)", Location Information Server (LIS)",
skipping to change at page 22, line 35 skipping to change at page 22, line 18
June 2002. June 2002.
[RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation [RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation
Protocol (SIP): Locating SIP Servers", RFC 3263, Protocol (SIP): Locating SIP Servers", RFC 3263,
June 2002. June 2002.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
with Session Description Protocol (SDP)", RFC 3264, with Session Description Protocol (SDP)", RFC 3264,
June 2002. June 2002.
[RFC3265] Roach, A., "Session Initiation Protocol (SIP)-Specific
Event Notification", RFC 3265, June 2002.
[RFC3325] Jennings, C., Peterson, J., and M. Watson, "Private [RFC3325] Jennings, C., Peterson, J., and M. Watson, "Private
Extensions to the Session Initiation Protocol (SIP) for Extensions to the Session Initiation Protocol (SIP) for
Asserted Identity within Trusted Networks", RFC 3325, Asserted Identity within Trusted Networks", RFC 3325,
November 2002. November 2002.
[RFC3428] Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C., [RFC3428] Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C.,
and D. Gurle, "Session Initiation Protocol (SIP) Extension and D. Gurle, "Session Initiation Protocol (SIP) Extension
for Instant Messaging", RFC 3428, December 2002. for Instant Messaging", RFC 3428, December 2002.
[RFC3515] Sparks, R., "The Session Initiation Protocol (SIP) Refer [RFC3515] Sparks, R., "The Session Initiation Protocol (SIP) Refer
skipping to change at page 23, line 18 skipping to change at page 22, line 52
Configuration Protocol Option for Coordinate-based Configuration Protocol Option for Coordinate-based
Location Configuration Information", RFC 3825, July 2004. Location Configuration Information", RFC 3825, July 2004.
[RFC3841] Rosenberg, J., Schulzrinne, H., and P. Kyzivat, "Caller [RFC3841] Rosenberg, J., Schulzrinne, H., and P. Kyzivat, "Caller
Preferences for the Session Initiation Protocol (SIP)", Preferences for the Session Initiation Protocol (SIP)",
RFC 3841, August 2004. RFC 3841, August 2004.
[RFC3856] Rosenberg, J., "A Presence Event Package for the Session [RFC3856] Rosenberg, J., "A Presence Event Package for the Session
Initiation Protocol (SIP)", RFC 3856, August 2004. Initiation Protocol (SIP)", RFC 3856, August 2004.
[RFC3920] Saint-Andre, P., Ed., "Extensible Messaging and Presence
Protocol (XMPP): Core", RFC 3920, October 2004.
[RFC3966] Schulzrinne, H., "The tel URI for Telephone Numbers", [RFC3966] Schulzrinne, H., "The tel URI for Telephone Numbers",
RFC 3966, December 2004. RFC 3966, December 2004.
[RFC3984] Wenger, S., Hannuksela, M., Stockhammer, T., Westerlund, [RFC3984] Wenger, S., Hannuksela, M., Stockhammer, T., Westerlund,
M., and D. Singer, "RTP Payload Format for H.264 Video", M., and D. Singer, "RTP Payload Format for H.264 Video",
RFC 3984, February 2005. RFC 3984, February 2005.
[RFC4028] Donovan, S. and J. Rosenberg, "Session Timers in the [RFC4028] Donovan, S. and J. Rosenberg, "Session Timers in the
Session Initiation Protocol (SIP)", RFC 4028, April 2005. Session Initiation Protocol (SIP)", RFC 4028, April 2005.
skipping to change at page 24, line 13 skipping to change at page 23, line 43
Server-Side State", RFC 4507, May 2006. Server-Side State", RFC 4507, May 2006.
[RFC4676] Schulzrinne, H., "Dynamic Host Configuration Protocol [RFC4676] Schulzrinne, H., "Dynamic Host Configuration Protocol
(DHCPv4 and DHCPv6) Option for Civic Addresses (DHCPv4 and DHCPv6) Option for Civic Addresses
Configuration Information", RFC 4676, October 2006. Configuration Information", RFC 4676, October 2006.
[RFC4967] Rosen, B., "Dial String Parameter for the Session [RFC4967] Rosen, B., "Dial String Parameter for the Session
Initiation Protocol Uniform Resource Identifier", Initiation Protocol Uniform Resource Identifier",
RFC 4967, July 2007. RFC 4967, July 2007.
[RFC4975] Campbell, B., Mahy, R., and C. Jennings, "The Message
Session Relay Protocol (MSRP)", RFC 4975, September 2007.
[RFC5139] Thomson, M. and J. Winterbottom, "Revised Civic Location
Format for Presence Information Data Format Location
Object (PIDF-LO)", RFC 5139, February 2008.
Appendix A. BCP Requirements Sorted by Responsible Party Appendix A. BCP Requirements Sorted by Responsible Party
A.1. Requirements of End Devices A.1. Requirements of End Devices
ED-1 if a user could reasonably expect to be able to place a call for ED-1 A device or application SHOULD support emergency calling if a
help with the device, then the device or application SHOULD support user could reasonably expect to be able to place a call for help with
emergency calling. the device.
ED-2 Devices that create media sessions and exchange audio, video ED-2 Devices that create media sessions and exchange audio, video
and/or text, and have the capability to establish sessions to a wide and/or text, and have the capability to establish sessions to a wide
variety of addresses, and communicate over private IP networks or the variety of addresses, and communicate over private IP networks or the
Internet, SHOULD support emergency calls Internet, SHOULD support emergency calls.
ED-3 Endpoints SHOULD do dial string recognition of emergency dial ED-3 Endpoints SHOULD recognize dial strings of emergency calls. If
strings the service provider always knows the location of the device, then
the service provider could recognize them.
ED-4 Emergency calls MUST be marked with a Service URN in the ED-4 Emergency calls MUST be marked with a Service URN in the
Request-URI of the INVITE. Request-URI of the INVITE.
ED-5 Local dial strings MUST be recognized. ED-5 Local dial strings MUST be recognized.
ED-6 Home dial strings MAY be recognized. ED-6 Home dial strings MAY be recognized.
ED-7 Local emergency dial strings SHOULD be determined from LoST LoST ED-7 Local emergency dial strings SHOULD be determined from LoST
[I-D.ietf-ecrit-lost]. [I-D.ietf-ecrit-lost].
ED-8 Endpoints which do not recognize emergency dial strings SHOULD ED-8 Endpoints which do not recognize emergency dial strings SHOULD
send dial strings as per [RFC4967]. send dial strings as per [RFC4967].
ED-9 Endpoints SHOULD be able to have home dial strings provisioned ED-9 Endpoints SHOULD be able to have home dial strings provisioned
by configuration. by configuration.
ED-10 Devices SHOULD NOT have one button emergency calling ED-10 Devices SHOULD NOT have one button emergency calling
initiation. initiation.
ED-11 All emergency services specified in ED-11 All emergency services specified in
[I-D.ietf-ecrit-service-urn] MUST be recognized. Devices/Service [I-D.ietf-ecrit-service-urn] MUST be recognized.
Providers MUST be capable of recognizing all of the associated dial
strings.
ED-12 Endpoints and Service Providers MUST be prepared to handle ED-12 Endpoints, Intermediate Devices and Service Providers MUST be
location represented in either civic or geo form. prepared to handle location represented in either civic or geo form.
ED-13 Elements MUST NOT convert (civic to geo or geo to civic) from ED-13 Elements MUST NOT convert (civic to geo or geo to civic) from
the form of location the determination mechanism supplied. the form of location the determination mechanism supplied.
ED-14 Any suitable location determination mechanism MAY be used. ED-14 Any suitable location determination mechanism MAY be used.
ED-15 Devices and/or access networks SHOULD support a manual method ED-15 Devices, intermediate Devices and/or access networks SHOULD
to "override" the location the access network determines. Where a support a manual method to "override" the location the access network
civic form of location is provided, all fields in the PIDF- LO determines. Where a civic form of location is provided, all fields
[RFC4119] and [I-D.ietf-geopriv-revised-civic-lo] MUST be able to be in the PIDF-LO [RFC4119] and [RFC5139] MUST be able to be specified.
specified.
ED-16 devices MAY support end-system measured location. Uncertainty ED-16 Devices MAY support end-system measured location. Uncertainty
of less than 100 m with 95% confidence SHOULD be available for of less than 100 m with 95% confidence SHOULD be available for
dispatch. dispatch.
ED-17 Devices that support endpoint measuring of location MUST have ED-17 Devices that support endpoint measuring of location MUST have
at least a coarse location (<1km) capability at all times for routing at least a coarse location capability (typically <1km accuracy when
of calls. This mechanism MAY be a service provided by the access not location hiding) at all times for routing of calls. This
network. mechanism MAY be a service provided by the access network.
ED-18 Endpoints SHOULD do location configuration themselves. ED-18 Endpoints SHOULD do configure their own location.
ED-19 Where proxies provide location on behalf of endpoints, the the ED-19 Where proxies provide location on behalf of endpoints, the the
service provider MUST ensure that either the end device is provided service provider MUST ensure that either the end device is provided
with the local dial strings for its current location (where the end with the local dial strings for its current location (where the end
device recognizes dial strings), or that the service provider can device recognizes dial strings), or the service provider proxy MUST
detect the appropriate local dial strings at the time of the call. detect the appropriate local dial strings at the time of the call.
ED-20 Devices SHOULD be able to accept and forward location by value ED-20 Devices SHOULD be able to accept and forward location by value
or by reference. An end device that receives location by reference or by reference. An end device that receives location by reference
(and does not also get the corresponding value) MUST be able to (and does not also get the corresponding value) MUST be able to
perform a dereference operation to obtain a value. perform a dereference operation to obtain a value.
ED-21 endpoints MUST support all of: DHCP Location options [RFC4676] ED-21 Devices MUST support all of: DHCP location options [RFC4676]
and [RFC3825], HELD[I-D.ietf-geopriv-http-location-delivery] and and [RFC3825], HELD[I-D.ietf-geopriv-http-location-delivery] and
LLDP-MED[LLDP-MED]. LLDP-MED[LLDP-MED].
ED-22 Endpoints SHOULD try all LCPs supported by the device in any ED-22 Endpoints SHOULD try all LCPs supported by the device in any
order or in parallel. The first one that succeeds in supplying order or in parallel. The first one that succeeds in supplying
location can be used. location can be used.
ED-23 Endpoints SHOULD obtain location immediately after obtaining ED-23 When HELD is the LCP, the request MUST specify a value of
local network configuration information. "emergencyRouting" for the "responseTime" parameter and use the
resulting location for routing. If a value for dispatch location
will be sent, another request with the "responseTime" parameter set
to "emergencyDispatch" must be completed, with the result sent for
dispatch purposes.
ED-24 To minimize the effects of non-bypassable VPNs, location ED-24 Where the operating system supporting application programs
configuration SHOULD be attempted before such tunnels are which need location for emergency calls does not allow access to
established. Layer 2 and Layer 3 functions necessary for a client application to
use DHCP location options and/or LLDP-MED, the operating system MUST
provide a published API conforming to ED-12 through ED-18 and ED-21
through ED-27. It is RECOMMENDED that all operating systems provide
such an API.
ED-25 Software which uses LCPs SHOULD locate and use the actual ED-25 Endpoints SHOULD obtain location immediately after obtaining
local network configuration information.When HELD is the LCP the
client MUST support a random back-off period (between 30 seconds and
300 seconds) for re-trying the HELD query, when no response is
received.
ED-26 If the device is configured to use DHCP for bootstrapping, it
MUST include both options for location acquisition (civic and
geodetic), the option for LIS discovery, and the option for LoST
discovery as defined in [RFC4676], [RFC3825],
[I-D.thomson-geopriv-lis-discovery] and
[I-D.ietf-ecrit-dhc-lost-discovery].
ED-27 If the device sends a DHCP INFORM message, it MUST include both
options for location acquisition (civic and geodetic), the option for
LIS discovery, and the option for LoST discovery as defined in
[RFC4676], [RFC3825], [I-D.thomson-geopriv-lis-discovery] and
[I-D.ietf-ecrit-dhc-lost-discovery].
ED-28 To minimize the effects of VPNs that do not allow split
tunneling VPNs, location configuration SHOULD be attempted before
such tunnels are established.
ED-29 Software which uses LCPs SHOULD locate and use the actual
hardware network interface rather than a VPN tunnel interface to hardware network interface rather than a VPN tunnel interface to
direct LCP requests to the LIS in the actual access network. direct LCP requests to the LIS in the actual access network.
ED-26 For devices which are not expected to roam, refreshing on the ED-30 For devices which are not expected to roam, refreshing location
order of once per day is RECOMMENDED on the order of once per day is RECOMMENDED.
ED-27 For devices which roam, refresh of location SHOULD be more ED-31 For devices which roam, refresh of location information SHOULD
frequent, with the frequency related to the mobility of the device be more frequent, with the frequency related to the mobility of the
and the ability of the access network to support the refresh device and the ability of the access network to support the refresh
operation. There can be instances in which a device is aware of when operation. If the device can detect that it has moved, for example
it moves, for example when it changes access points. When this type when it changes access points, the device SHOULD refresh its
of event occurs, the device SHOULD refresh its location. location.
ED-28 It is RECOMMENDED that location determination not take longer ED-32 It is RECOMMENDED that location determination not take longer
than 250 ms to obtain routing location and systems SHOULD be designed than 250 ms to obtain routing location and systems SHOULD be designed
such that the typical response is under 100ms. However, as much as 3 such that the typical response is under 100 ms. However, as much as
seconds to obtain routing location MAY be tolerated if location 3 seconds to obtain routing location MAY be tolerated if location
accuracy can be substantially improved over what can be obtained in accuracy can be substantially improved over what can be obtained in
250 ms. 250 ms.
ED-29 Location sent between SIP elements MUST be conveyed using ED-33 Location sent between SIP elements MUST be conveyed using
[I-D.ietf-sip-location-conveyance]. [I-D.ietf-sip-location-conveyance].
ED-30 Where the absolute location or the accuracy of location of the ED-34 Where the absolute location or the accuracy of location of the
endpoint may change between the time the call is received at the PSAP endpoint may change between the time the call is received at the PSAP
and the time dispatch is completed, location update mechanisms MUST and the time dispatch is completed, location update mechanisms MUST
be provided. be provided.
ED-31 mobile devices MUST be provided with a mechanism to get ED-35 Mobile devices MUST be provided with a mechanism to get
repeated location updates to track the motion of the device during repeated location updates to track the motion of the device during
the complete processing of the call. the complete processing of the call.
ED-32 The LIS SHOULD provide a location reference which permits a ED-36 The LIS SHOULD provide a location reference which permits a
subscription with appropriate filtering. subscription with appropriate filtering.
ED-33 For calls sent with location-by-reference, with a SIP or SIPS ED-37 For calls sent with location-by-reference, with a SIP or SIPS
scheme, the server resolving the reference MUST support a SUBSCRIBE scheme, the server resolving the reference MUST support a SUBSCRIBE
[RFC3118] to the presence event [RFC3856]. For other location-by- [RFC3265] to the presence event [RFC3856]. For other location-by-
reference schemes, a repeated location dereference by the PSAP MUST reference schemes, the PSAP will have to repeatedly dereference the
be supported. URI to determine if the device moved.
ED-34 If location was sent by value, and the endpoint gets updated ED-38 If location was sent by value, and the endpoint gets updated
location, it MUST send the updated location to the PSAP via reINVITE location, it MUST send the updated location to the PSAP via a SIP re-
or UPDATE. Such updates SHOULD be limited to no more than one update INVITE or UPDATE request. Such updates SHOULD be limited to no more
every 10 seconds. than one update every 10 seconds.
ED-35 If a UA has more than one location available to it, it MUST ED-39 If a UA has more than one location available to it, it MUST
choose one location to use to route the call towards the PSAP. choose one location to route the call towards the PSAP.
ED-36/ Location objects MUST contain information about the method by ED-40 Location objects MUST contain information about the method by
which the location was determined, such as GPS, manually entered, or which the location was determined, such as GPS, manually entered, or
based on access network topology included in a PIDF- LO ?method? based on access network topology included in a PIDF- LO "method"
element. In addition, the source of the location information MUST be element. In addition, the source of the location information MUST be
included in a PIDF-LO "provided-by" element. included in a PIDF-LO "provided-by" element.
ED-37 The "used-for-routing" parameter MUST be set to the location ED-41 The "used-for-routing" parameter MUST be set to the location
that was used to query LoST. that was used to query LoST.
ED-38 Endpoints SHOULD validate civic locations when they receive ED-42 Endpoints SHOULD validate civic locations when they receive
them from their LCP. Validation SHOULD be performed in conjunction them from their LCP. Validation SHOULD be performed in conjunction
with the LoST route query to minimize load on the LoST server. with the LoST route query to minimize load on the LoST server.
ED-39 If the LCP does not return location in the form of a PIDF-LO ED-43 If the LCP does not return location in the form of a PIDF-LO
[RFC4119], the endpoint MUST map the location information it receives [RFC4119], the endpoint MUST map the location information it receives
from the configuration protocol to a PIDF-LO. from the configuration protocol to a PIDF-LO.
ED-40 To prevent against spoofing of the DHCP server, elements ED-44 To prevent against spoofing of the DHCP server, elements
implementing DHCP for location configuration SHOULD use [RFC3118]. implementing DHCP for location configuration SHOULD use although the
difficulty in providing appropriate credentials is significant.
ED-41 S/MIME MUST NOT be used to protect the Geolocation header or [RFC3118].
bodies.
ED-42 TLS MUST be used to protect location (but see Section 9.1).
ED-43 Uninitialized devices SHOULD NOT lead a user to believe an ED-45 S/MIME MUST NOT be used to encrypt the SIP Geolocation header
emergency call could be placed on it unless local regulations require or bodies.
it.
ED-44 Uninitialized devices SHOULD NOT be capable of placing an ED-46 TLS MUST be used to protect location (but see Section 9.1).
emergency call unless local regulations require it. IPSEC [RFC2401] is an acceptable alternative.
ED-45 Uninitialized devices that can place emergency calls MUST ED-47 Endpoints MUST support one or more mechanisms that allow them
supply location the same as a fully capable device would. to determine their public IP address. Examples include ICE
[I-D.ietf-mmusic-ice] and HTTP get.
ED-46 Unitialized Devices MUST supply a call back URI. See Section 7 ED-48 Endpoints MUST support LIS discovery as described in
[I-D.thomson-geopriv-lis-discovery], and the LoST discovery as
described in [I-D.ietf-ecrit-dhc-lost-discovery].
ED-47 Unitialized Devices MUST include identifiers in the signaling ED-49 The device MUST have a configurable default LoST server
that can be used by the service provider to identify the device and parameter. If the device is provided by or managed by service
to allow filtering of calls from the device by the PSAP/ESRP. provider, it is expected that the service provider will configure
this option.
ED-48 Endpoints who obtain their own location SHOULD perform LoST ED-50 Endpoints who obtain their own location SHOULD perform LoST
mapping to the PSAP URI whenever they get an initial or updated mapping to the PSAP URI.
location.
ED-49 Mapping SHOULD be performed at boot time and whenever location ED-51 Mapping SHOULD be performed at boot time and whenever location
changes beyond the service boundary obtained from a prior LoST changes beyond the service boundary obtained from a prior LoST
mapping operation or the time-to-live value of that response has mapping operation or the time-to-live value of that response has
expired. The value MUST be cached for possible use. expired. The value MUST be cached for possible later use.
ED-50 The endpoint MUST attempt to update its location at the time of ED-52 The endpoint MUST attempt to update its location at the time of
an emergency call. If it cannot obtain a new location quickly (See an emergency call. If it cannot obtain a new location quickly (see
Section 6), it MUST use the cached value. Section 6), it MUST use the cached value.
ED-51 The endpoint SHOULD attempt to update the LoST mapping at the ED-53 The endpoint SHOULD attempt to update the LoST mapping at the
time of an emergency call. If it cannot obtain a new mapping time of an emergency call. If it cannot obtain a new mapping
quickly, it MUST use the cached value. quickly, it MUST use the cached value if it has one.
ED-52 [RFC3261] and [RFC3263] procedures MUST be used to route an ED-54 [RFC3261] and [RFC3263] procedures MUST be used to route an
emergency call towards the PSAP's URI. emergency call towards the PSAP's URI.
ED-53 Initial INVITES MUST provide an Offer [RFC3264] ED-55 Initial INVITES MUST provide an Offer [RFC3264].
ED-54 Best Current Practice for SIP user agents [RFC4504] including ED-56 Best Current Practice for SIP user agents [RFC4504] including
handling of audio, video and real-time text [RFC4103] SHOULD be handling of audio, video and real-time text [RFC4103] SHOULD be
applied. This memo can be considered as an addition to [RFC4504] for applied. This memo can be considered as an addition to [RFC4504] for
endpoints. endpoints.
ED-55 TLS MUST be specified when attempting to signal an emergency ED-57 TLS MUST be specified when attempting to signal an emergency
call with SIP per [I-D.ietf-sip-sips]. IPSEC [RFC2401] is an call with SIP per [I-D.ietf-sip-sips]. IPSEC [RFC2401] is an
acceptable alternative. acceptable alternative.
ED-56 If TLS session establishment fails, the call MUST be retried ED-58 If TLS session establishment fails, the call MUST be retried
with sip: without TLS.
ED-57 [I-D.ietf-sip-outbound] is RECOMMENDED to maintain persistent ED-59 [I-D.ietf-sip-outbound] is RECOMMENDED to maintain persistent
TLS connections between elements TLS connections between elements.
ED-58 https: MUST be specified when attempting to retrieve location ED-60 TLS MUST be specified when attempting to retrieve location
(configuration or dereferencing) with HELD. The use of [RFC4507] is (configuration or dereferencing) with HELD. The use of [RFC4507] is
RECOMMENDED to minimise the time to establish TLS sessions. RECOMMENDED to minimise the time to establish TLS sessions.
ED-59 If TLS session establishment fails, the location retrieveal ED-61 If TLS session establishment fails, the location retrieveal
MUST be retried with http: MUST be retried without TLS.
ED-60 The initial SIP signaling Method is an INVITE: ED-62 The initial SIP signaling method is an INVITE request:
1. The Request URI SHOULD be the service URN in the "sos" tree, If 1. The Request URI SHOULD be the service URN in the "sos" tree, If
the device cannot do local dialstring interpretation, the the device cannot interpert local dial strings, the Request-URI
Request-URI SHOULD be a dialstring URI [RFC4967] with the dialed SHOULD be a dial string URI [RFC4967] with the dialed digits.
digits. 2. The To header SHOULD be a service URN in the "sos" tree. If the
device cannot do interpret local dial strings, the To: SHOULD be
2. The To: header MUST be present and SHOULD be a service URN in a dial string URI with the dialed digits.
the "sos" tree. If the device cannot do local dialstring 3. The From header MUST be present and SHOULD be the AoR of the
interpretation, the To: SHOULD be a dialstring URI with the
dialed digits.
3. The From: header MUST be present and SHOULD be the AoR of the
caller. caller.
4. A Via: header MUST be present and SHOULD include the URI of the 4. A Via header MUST be present.
device. 5. A Route header SHOULD be present with a PSAP URI obtained from
5. A Route: header SHOULD be present with a PSAP URI obtained from LoST (see Section 8) and the loose route parameter. If the
LoST (see Section 8 ) and the loose route parameter. A sips URI device does not interpet dial plans, or was unable to obtain a
[RFC3261] SHOULD be specified, unless the operation must be route from a LoST serverr, no Route header will be present.
retried due to a failure to establish a TLS connection. If the
device does not do dial plan interpretation, no Route: header
will be present.
6. A Contact header MUST be present which MUST be globally 6. A Contact header MUST be present which MUST be globally
routable, for example a GRUU [I-D.ietf-sip-gruu], to permit an routable, for example a GRUU [I-D.ietf-sip-gruu], to permit an
immediate call-back to the specific device which placed the immediate call-back to the specific device which placed the
emergency call. emergency call.
7. Other headers MAY be included as per normal sip behavior. 7. Other headers MAY be included as per normal SIP behavior.
8. A Supported: header MUST be included with the 'geolocation' 8. A Supported header MUST be included with the 'geolocation'
option tag [I-D.ietf-sip-location-conveyance], unless the device option tag [I-D.ietf-sip-location-conveyance], unless the device
does not understand the concept of SIP Location. does not understand the concept of SIP location.
9. If a device understands the SIP Location Conveyance 9. If a device understands the SIP location conveyance
[I-D.ietf-sip-location-conveyance] extension and has its [I-D.ietf-sip-location-conveyance] extension and has its
location available, it MUST include location either by- value or location available, it MUST include location either by-value,
by-reference. by-reference or both.
10. If a device understands the SIP Location Conveyance extension 10. If a device understands the SIP Location Conveyance extension
and has its location unavailable or unknown to that device, it and has its location unavailable or unknown to that device, it
MUST include a Supported header with a "geolocation" option tag, MUST include a Supported header with a "geolocation" option tag,
and MUST NOT include a Geolocation header, and not include a and MUST NOT include a Geolocation header, and not include a
PIDF-LO message body. PIDF-LO message body.
11. If a device understands the SIP Location Conveyance extension 11. If a device understands the SIP Location Conveyance extension
and supports LoST [I-D.ietf-ecrit-lost] then whichever location and supports LoST [I-D.ietf-ecrit-lost], the Geolocation "used-
is used for routing the message towards the PSAP or ESRP, even for-routing" header parameter MUST be added to the corresponding
if there is only one, the Geolocation "used-for-routing" header URI in the Geolocation header.
parameter SHOULD be added to the corresponding URI in the
Geolocation header.
12. A normal SDP offer SHOULD be included in the INVITE. If voice 12. A normal SDP offer SHOULD be included in the INVITE. If voice
is supported the offer MUST include the G.711 codec, see is supported the offer MUST include the G.711 codec, see
Section 14. Section 14.
13. If the device includes location-by-value, the UA MUST support 13. If the device includes location-by-value, the UA MUST support
multipart message bodies, since SDP will likely be also in the multipart message bodies, since SDP will likely be also in the
INVITE. INVITE.
14. A UAC SHOULD include a "inserted-by=endpoint" header parameter 14. A UAC SHOULD include a "inserted-by=endpoint" header parameter
on all Geolocation headers . This informs downstream elements on all Geolocation headers . This informs downstream elements
which device entered the location at this URI (either cid-URL or which device entered the location at this URI (either cid-URL or
location-by-reference URI). location-by-reference URI).
skipping to change at page 30, line 4 skipping to change at page 30, line 15
12. A normal SDP offer SHOULD be included in the INVITE. If voice 12. A normal SDP offer SHOULD be included in the INVITE. If voice
is supported the offer MUST include the G.711 codec, see is supported the offer MUST include the G.711 codec, see
Section 14. Section 14.
13. If the device includes location-by-value, the UA MUST support 13. If the device includes location-by-value, the UA MUST support
multipart message bodies, since SDP will likely be also in the multipart message bodies, since SDP will likely be also in the
INVITE. INVITE.
14. A UAC SHOULD include a "inserted-by=endpoint" header parameter 14. A UAC SHOULD include a "inserted-by=endpoint" header parameter
on all Geolocation headers . This informs downstream elements on all Geolocation headers . This informs downstream elements
which device entered the location at this URI (either cid-URL or which device entered the location at this URI (either cid-URL or
location-by-reference URI). location-by-reference URI).
15. SIP Caller Preferences [RFC3841] MAY be used to signal how the 15. SIP Caller Preferences [RFC3841] MAY be used to signal how the
PSAP should handle the call. PSAP should handle the call. For example, a language preference
expressed in an Accept-Language header may be used as a hint to
cause the PSAP to route the call to a call taker who speaks the
requested language. SIP Caller Preferences may also be used to
indicate a need to invoke a relay service for communication with
people with disabilities in the call.
ED-61 During the course of an emergency call, devices and proxies ED-63 During the course of an emergency call, devices and proxies
MUST support REFER transactions and the Referred-by: header MUST support REFER transactions and the Referred-by: header
[RFC3515]. [RFC3515].
ED-62 User agents and proxies MUST Support Session Timer [RFC4028] to ED-64 User agents and proxies MUST support Session Timer [RFC4028] to
guard against session corruption. guard against session corruption.
ED-63 UACs with an active emergency call (i.e. SIP Dialog) MUST NOT ED-65 UACs with an active emergency call (i.e. SIP Dialog) MUST NOT
generate a BYE request (or equivalent for other non-SIP signaling). generate a BYE request (or equivalent for other non-SIP signaling).
The PSAP must be the only entity that can terminate a call. If the The PSAP must be the only entity that can terminate a call. If the
user "hangs up" an emergency call, the device should alert, and when user "hangs up" an emergency call, the device should alert the user,
answered, reconnect the caller to the PSAP. and if the user responds by attempting to pick up the call, the
device MUST reconnect the caller to the PSAP.
ED-64 There can be a case where the session signaling path is lost, ED-66 There can be a case where the session signaling path is lost,
and the user agent does not receive the BYE. If the call is hung up, and the user agent does not receive the BYE. If the call is hung up,
and the session timer expires the call MAY be declared lost. If in and the session timer (if implemented) expires, the call MAY be
the interval, an incoming call is received from the domain of the declared lost. If in the interval, an incoming call is received from
PSAP, the device SHOULD drop the old call and alert for the (new) the domain of the PSAP, the device MUST drop the old call and alert
incoming call. Dropping of the old call SHOULD only occur if the for the (new) incoming call. Dropping of the old call MUST only
user is attempting to hang up; the domain of an incoming call can occur if the user is attempting to hang up; the domain of an incoming
only be determined from the From header, which is not reliable, and call can only be determined from the From header, which is not
could be spoofed. Dropping an active call by a new call with a reliable, and could be spoofed. Dropping an active call by a new
spoofed From: would be a DoS attack. call with a spoofed From: would be a DoS attack.
ED-65 User Agents and proxys MUST disable outgoing call features such ED-67 User Agents and proxys MUST disable outgoing call features such
as: as
o Call Waiting o Call Waiting
o Call Transfer o Call Transfer
o Three Way Call o Three Way Call
o Flash hold o Flash hold
o Outbound Call Blocking o Outbound Call Blocking
when an emergency call is established. Also see ED-72 in Section 14. when an emergency call is established. Also see ED-72 in Section 14.
ED-66 The emergency dialstrings SHOULD NOT be permitted in Call ED-68 The emergency dialstrings SHOULD NOT be permitted in Call
Forward numbers or speed dial lists. Forward numbers or speed dial lists.
ED-67 The User Agent and Proxies SHOULD disable the following ED-69 The User Agent and Proxies SHOULD disable the following
incoming call features on call backs from the PSAP: incoming call features on call backs from the PSAP:
o Call Waiting o Call Waiting
o Do Not Disturb o Do Not Disturb
o Call Forward (all kinds) o Call Forward (all kinds)
ED-68 Call backs SHOULD be determined by retaining the domain of the ED-70 Call backs SHOULD be determined by retaining the domain of the
PSAP which answers an outgoing emergency call and instantiating a PSAP which answers an outgoing emergency call and instantiating a
timer which starts when the call is terminated. If a call is timer which starts when the call is terminated. If a call is
received from the same domain and within the timer period, sent to received from the same domain and within the timer period, sent to
the Contact: or AoR used in the emergency call, it should be assumed the Contact: or AoR used in the emergency call, it should be assumed
to be a call back. The suggested timer period is 5 minutes. to be a call back. The suggested timer period is 5 minutes.
ED-69 Endpoints MUST send and receive media streams on RTP [RFC3550]. ED-71 Endpoints MUST send and receive media streams on RTP [RFC3550].
ED-70 Normal SIP offer/answer [RFC3264] negotiations MUST be used to ED-72 Normal SIP offer/answer [RFC3264] negotiations MUST be used to
agree on the media streams to be used. agree on the media streams to be used.
ED-71 Endpoints supporting voice MUST support G.711 A law (and mu Law ED-73 Endpoints supporting voice MUST support G.711 A law (and mu Law
in North America) encoded voice as described in [RFC3551]. It is if they could be used in North America) encoded voice as described in
desirable to support wideband codecs in the offer. [RFC3551]. It is desirable to include wideband codecs such as AMR-WB
in the offer.
ED-72 Silence suppression (Voice Activity Detection methods) MUST NOT ED-74 Silence suppression (Voice Activity Detection methods) MUST NOT
be used on emergency calls. PSAP call takers sometimes get be used on emergency calls. PSAP call takers sometimes get
information on what is happening in the background to determine how information on what is happening in the background to determine how
to process the call. to process the call.
ED-73 Endpoints supporting IM MUST support either [RFC3428] or ED-75 Endpoints supporting IM MUST support both [RFC3428] and
[RFC3920]. [RFC4975].
ED-74 Endpoints supporting real-time text MUST use [RFC4103]. The ED-76 Endpoints supporting real-time text MUST use [RFC4103]. The
expectations for emergency service support for the real-time text expectations for emergency service support for the real-time text
medium, described in [I-D.ietf-sipping-toip], section 7.1 SHOULD be medium, described in [I-D.ietf-sipping-toip], Section 7.1 SHOULD be
fulfilled. fulfilled.
ED-75 Endpoints supporting video MUST support H.264 per [RFC3984]. ED-77 Endpoints supporting video MUST support H.264 per [RFC3984].
ED-76 INVITE requests to a service urn with a urn parameter of "test" ED-78 INVITE requests to a service URN ending in ".test" indicates a
indicates a request for an automated test. For example, request for an automated test. For example,
"urn:service.sos.fire;test". As in standard SIP, a 200 (OK) response "urn:service.sos.fire.test". As in standard SIP, a 200 (OK) response
indicates that the address was recognized and a 404 (Not found) that indicates that the address was recognized and a 404 (Not found) that
it was not. A 486 (Busy Here) MUST be returned if the test service it was not. A 486 (Busy Here) MUST be returned if the test service
is busy, and a 488 (Not Acceptable Here) MUST be returned if the PSAP is busy, and a 488 (Not Acceptable Here) MUST be returned if the PSAP
does not support the test mechanism. does not support the test mechanism.
ED-77 In its response to the test, the PSAP MAY include a text body ED-79 In its response to the test, the PSAP MAY include a text body
(text/plain) indicating the identity of the PSAP, the requested (text/plain) indicating the identity of the PSAP, the requested
service, and the location reported with the call. For the latter, service, and the location reported with the call. For the latter,
the PSAP SHOULD return location-by-value even if the original the PSAP SHOULD return location-by-value even if the original
location delivered with the test was by-reference. If the location- location delivered with the test was by-reference. If the location-
by-reference was supplied, and the dereference requires credentials, by-reference was supplied, and the dereference requires credentials,
the PSAP SHOULD use credentials supplied by the LIS for test the PSAP SHOULD use credentials supplied by the LIS for test
purposes. This alerts the LIS that the dereference is not for an purposes. This alerts the LIS that the dereference is not for an
actual emergency call and location hiding techniques, if they are actual emergency call and location hiding techniques, if they are
being used, may be employed for this dereference. The response MAY being used, may be employed for this dereference. The response MAY
include the connected identity of the PSAP per include the connected identity of the PSAP per
[I-D.ietf-sip-connected-identity]. [I-D.ietf-sip-connected-identity].
ED-78 A PSAP accepting a test call SHOULD accept a media loopback ED-80 A PSAP accepting a test call SHOULD accept a media loopback
test [I-D.ietf-mmusic-media-loopback] and SHOULD support the "rtp- test [I-D.ietf-mmusic-media-loopback] and SHOULD support the "rtp-
pkt-loopback" and "rtp-start-loopback" options. The user agent would pkt-loopback" and "rtp-start-loopback" options. The user agent would
specify a loopback attribute of "loopback-source", the PSAP being the specify a loopback attribute of "loopback-source", the PSAP being the
mirror. User Agents should expect the PSAP to loop back no more than mirror. User Agents should expect the PSAP to loop back no more than
3 packets of each media type accepted (which limits the duration of 3 packets of each media type accepted (which limits the duration of
the test), after which the PSAP would normally send BYE. the test), after which the PSAP would normally send BYE.
ED-79 User agents SHOULD perform a full call test, including media ED-81 User agents SHOULD perform a full call test, including media
loopback, after a disconnect and subsequent change in IP address not loopback, after a disconnect and subsequent change in IP address not
due to a reboot. After an initial IP address assignment test, a full due to a reboot. After an initial test, a full test SHOULD be
test SHOULD be repeated approximately every 30 days with a random repeated approximately every 30 days with a random interval.
interval.
ED-80 User agents MUST NOT place a test call immediately after ED-82 User agents MUST NOT place a test call immediately after
booting. If the IP address changes after booting, the UA should wait booting. If the IP address changes after booting, the UA should wait
a random amount of time (in perhaps a 30 minute period, sufficient a random amount of time (in perhaps a 30 minute period, sufficient
for any avalanche restart to complete) and then test. for any avalanche restart to complete) and then test.
ED-81 PSAPs MAY refuse repeated requests for test from the same ED-83 PSAPs MAY refuse repeated requests for test from the same
device in a short period of time. Any refusal is signaled with a 486 device in a short period of time. Any refusal is signaled with a 486
or 488 response. or 488 response.
A.2. Requirements of Service Providers A.2. Requirements of Service Providers
SP-1 If a device or application expects to be able to place a call SP-1 If a device or application expects to be able to place a call
for help, the service that supports it SHOULD facilitate emergency for help, the service provider that supports it MUST facilitate
calling. emergency calling.
SP-2 Proxy servers SHOULD do dial string recognition of emergency SP-2 Proxy servers SHOULD recognize emergency dial string if for some
dial strings if for some reason the endpoint does not recognize them. reason the endpoint does not recognize them. This cannot be relied
upon by the device if the service provider cannot always determine
the location of the device.
SP-3 Emergency calls MUST be marked with a Service URN in the SP-3 Emergency calls MUST be marked with a Service URN in the
Request-URI of the INVITE. Request-URI of the INVITE.
SP-4 Local dial strings MUST be recognized. SP-4 Local dial strings MUST be recognized.
SP-5 Home dial strings MAY be recognized. SP-5 Home dial strings MAY be recognized.
SP-6 Local emergency dial strings SHOULD be determined from LoST LoST SP-6 Local emergency dial strings SHOULD be determined from LoST
[I-D.ietf-ecrit-lost]. [I-D.ietf-ecrit-lost].
SP-7 Proxy Servers MUST recognize emergency dial strings represented SP-7 Proxy Servers MUST recognize emergency dial strings represented
by [RFC4967] and SHOULD recognize dial strings represented by a tel by [RFC4967] and SHOULD recognize emergency dial strings represented
URI [RFC3966]. by a tel URI [RFC3966].
SP-8 Service providers MAY provide home dial strings by configuration SP-8 Service providers MAY provide home dial strings by configuration
[I-D.ietf-sipping-config-framework]. [I-D.ietf-sipping-config-framework].
SP-9 All emergency services specified in [I-D.ietf-ecrit-service-urn] SP-9 All emergency services specified in [I-D.ietf-ecrit-service-urn]
MUST be recognized. Devices/Service Providers MUST be capable of MUST be recognized.
recognizing all of the associated dial strings.
SP-10 Endpoints and Service Providers MUST be prepared to handle SP-10 Endpoints, Intermediate Devices and Service Providers MUST be
location represented in either civic or geo form. prepared to handle location represented in either civic or geo form.
SP-11 Elements MUST NOT convert (civic to geo or geo to civic) from SP-11 Elements MUST NOT convert (civic to geo or geo to civic) from
the form of location the determination mechanism supplied. the form of location the determination mechanism supplied.
SP-12 Proxies MAY provide location on behalf of devices it supports SP-12 Proxies MAY provide location on behalf of devices if:
if: o The proxy has a relationship with all access networks the device
o It has a relationship with all access networks the device could could connect to, and the relationship allows it to obtain
connect to, and the relationship allows it to obtain location. location.
o It has an identifier that can be used by the access network to o The proxy has an identifier, such as an IP address, that can be
determine the location of the endpoint, particularly in the used by the access network to determine the location of the
presence of NAT and VPN tunnels that may exist between the access endpoint, even in the presence of NAT and VPN tunnels that may
network and the service provider. obscure the identifier between the access network and the service
provider.
SP-13 Where proxies provide location on behalf of endpoints, the the SP-13 Where proxies provide location on behalf of endpoints, the the
service provider MUST ensure that either the end device is provided service provider MUST ensure that either the end device is provided
with the local dial strings for its current location (where the end with the local dial strings for its current location (where the end
device recognizes dial strings), or that the service provider can device recognizes dial strings), or the service provider proxy MUST
detect the appropriate local dial strings at the time of the call. detect the appropriate local dial strings at the time of the call.
SP-14 Location sent between SIP elements MUST be conveyed using SP-14 When HELD is the LCP, the request MUST specify a value of
"emergencyRouting" for the "responseTime" parameter and use the
resulting location for routing. If a value for dispatch location
will be sent, another request with the "responseTime" parameter set
to "emergencyDispatch" must be completed, with the result sent for
dispatch purposes.
SP-15 Location sent between SIP elements MUST be conveyed using
[I-D.ietf-sip-location-conveyance]. [I-D.ietf-sip-location-conveyance].
SP-15 If a proxy inserts location on behalf of an endpoint, and it SP-16 If a proxy inserts location on behalf of an endpoint, and it
has multiple locations available for the endpoint it MUST choose one has multiple locations available for the endpoint it MUST choose one
location to use to route the call towards the PSAP. location to use to route the call towards the PSAP.
SP-16 If a proxy is attempting to assert location but the UA conveyed SP-17 If a proxy is attempting to insert location but the UA conveyed
a location to it, the proxy must use the UA?s location for routing a location to it, the proxy MUST use the UA's location for routing
and MUST convey that location towards the PSAP. It MAY also include and MUST convey that location towards the PSAP. It MAY also include
what it believes the location to be. what it believes the location to be in a separate Geolocation header.
SP-17 All location objects received by a proxy MUST be delivered to SP-18 All location objects received by a proxy MUST be delivered to
the PSAP. the PSAP.
SP-18 Location objects MUST contain information about the method by SP-19 Location objects MUST contain information about the method by
which the location was determined, such as GPS, manually entered, or which the location was determined, such as GPS, manually entered, or
based on access network topology included in a PIDF- LO ?method? based on access network topology included in a PIDF- LO "method"
element. In addition, the source of the location information MUST be element. In addition, the source of the location information MUST be
included in a PIDF-LO "provided-by" element. included in a PIDF-LO "provided-by" element.
SP-19 The "used-for-routing" parameter MUST be set to the location SP-20 The "used-for-routing" parameter MUST be set to the location
that was used to query LoST. that was used to query LoST.
SP-20 Proxies handling emergency calls MUST insert a default location SP-21 Proxies handling emergency calls MUST insert a default location
if the call does not contain a location. if the call does not contain a location and the proxy does not have a
method for obtaining a better location.
SP-21 Default locations MUST be marked with method=Default and an SP-22 Default locations MUST be marked with method=Default and the
appropriate provided-by in the PIDF-LO. proxy MUST be identfied in provided-by element of the PIDF-LO.
SP-22 TLS MUST be used to protect location (but see Section 9.1). SP-23 TLS MUST be used to protect location (but see Section 9.1).
IPSEC [RFC2401] is an acceptable alternative. IPSEC [RFC2401] is an acceptable alternative.
SP-23 Uninitialized devices SHOULD NOT be capable of placing an SP-24 Networks MUST be designed so that at least one proxy in the
emergency call unless local regulations require it. outbound path can recognize emergency calls with a Request URI of the
service URN in the "sos" tree. An endpoint places a service URN in
SP-24 Uninitialized devices that can place emergency calls MUST the Request URI to indicate that the endpoint understood the call was
supply location the same as a fully capable device would. an emergency call. A proxy that processes such a call looks for the
presence of a SIP Route header field with a URI of a PSAP. Absence
SP-25 Unitialized Devices MUST supply a call back URI. See Section 7 of such a Route header indicates the UAC was unable to invoke LoST
and the proxy MUST perform the LoST mapping and insert a Route header
SP-26 Unitialized Devices MUST include identifiers in the signaling field with the URI obtained.
that can be used by the service provider to identify the device and
to allow filtering of calls from the device by the PSAP/ESRP.
SP-27 All proxies in the outbound path SHOULD recognize emergency
calls with a Request URI of the service URN in the "sos" tree. An
endpoint places a service URN in the Request URI to indicate that the
endpoint understood the call was an emergency call. A proxy that
processes such a call looks for the presence of a Route header with a
URI of a PSAP. Absence of such a Route header indicates the UAC was
unable to invoke LoST and the proxy MUST perform the LoST mapping and
insert a Route header with the URI obtained.
SP-28 To deal with old user agents that predate this specification SP-25 To deal with old user agents that predate this specification
and with UAs that do not have access to their own location data, and with UAs that do not have access to their own location data, a
proxies that recognize a call as an emergency call that is not marked proxy that recognizes a call as an emergency call that is not marked
as such (see Section 5) MUST also perform this mapping, with the best as such (see Section 5) MUST also perform this mapping, with the best
location it has available for the endpoint. The resulting PSAP URI location it has available for the endpoint. The resulting PSAP URI
would be placed in a Route header with the service URN in the Request would be placed in a Route header with the service URN in the Request
URI. URI.
SP-29 Proxy servers performing mapping SHOULD use location obtained SP-26 Proxy servers performing mapping SHOULD use location obtained
from the access network for the mapping. If no location is from the access network for the mapping. If no location is
available, a default location (see Section 6.11) MUST be supplied. available, a default location (see Section 6.11) MUST be supplied.
SP-30 A proxy server which attempts mapping and fails to get a SP-27 A proxy server which attempts mapping and fails to get a
mapping MUST provide a default mapping. A suitable default mapping mapping MUST provide a default mapping. A suitable default mapping
would be the mapping obtained previously for the default location would be the mapping obtained previously for the default location
appropriate for the caller. appropriate for the caller.
SP-31 [RFC3261] and [RFC3263] procedures MUST be used to route an SP-28 [RFC3261] and [RFC3263] procedures MUST be used to route an
emergency call towards the PSAP's URI. emergency call towards the PSAP's URI.
SP-32 TLS MUST be specified when attempting to signal an emergency SP-29 TLS MUST be specified when attempting to signal an emergency
call with SIP per [I-D.ietf-sip-sips]. IPSEC [RFC2401] is an call with SIP per [I-D.ietf-sip-sips]. IPSEC [RFC2401] is an
acceptable alternative. acceptable alternative.
SP-33 If TLS session establishment fails, the call MUST be retried SP-30 If TLS session establishment fails, the call MUST be retried
with sip: without TLS.
SP-34 [I-D.ietf-sip-outbound] is RECOMMENDED to maintain persistent SP-31 [I-D.ietf-sip-outbound] is RECOMMENDED to maintain persistent
TLS connections between elements TLS connections between elements.
SP-35 SIP Proxy servers processing emergency calls: SP-32 SIP Proxy servers processing emergency calls:
1. If the proxy does dial plan interpretation on behalf of user 1. If the proxy does interprets dial plans on behalf of user agents,
agents, the proxy MUST look for the local emergency dial string the proxy MUST look for the local emergency dial string at the
at the location of the end device and MAY look for the home dial location of the end device and MAY look for the home dial string.
string. If it finds it the proxy MUST: If it finds it, the proxy MUST:
* Insert a Geolocation header as per 10-12 above. Location-by- * Insert a Geolocation header as above. Location-by-reference
reference MUST be used because proxies may not insert bodies. MUST be used because proxies must not insert bodies.
* Include the Geolocation "inserted-by=server" AND "used-for- * Include the Geolocation "inserted-by=server" and "used-for-
routing" parameters. routing" parameters.
* Map the location to a PSAP uri using LoST. * Map the location to a PSAP URI using LoST.
* Add a Route header with the PSAP URI. * Add a Route header with the PSAP URI.
* Replace the Request-URI (which was the dialstring) with the * Replace the Request-URI (which was the dialstring) with the
service URN appropriate for the emergency dialstring. service URN appropriate for the emergency dialstring.
* Route the call using normal SIP routing mechanisms. * Route the call using normal SIP routing mechanisms.
2. If the proxy recognizes the service URN in the Request URI, and 2. If the proxy recognizes the service URN in the Request URI, and
does not find a Route header with a PSAP URI, it MUST run LoST does not find a Route header with a PSAP URI, it MUST run LoST
routing. If a location was provided (which should be the case), routing. If a location was provided (which should be the case),
the proxy uses that location to query LoST. The proxy may have the proxy uses that location to query LoST. The proxy may have
to dereference a location by reference to get a value. If a to dereference a location by reference to get a value. If a
location is not present, and the proxy can query a LIS which has location is not present, and the proxy can query a LIS which has
the location of the UA it MUST do so. If no location is present, the location of the UA it MUST do so. If no location is present,
and the proxy does not have access to a LIS which could provide and the proxy does not have access to a LIS which could provide
location, the proxy MUST supply a default location (See location, the proxy MUST supply a default location (See
Section 6.11). The location (in the signaling, obtained from a Section 6.11). The location (in the signaling, obtained from a
skipping to change at page 35, line 43 skipping to change at page 36, line 18
the proxy uses that location to query LoST. The proxy may have the proxy uses that location to query LoST. The proxy may have
to dereference a location by reference to get a value. If a to dereference a location by reference to get a value. If a
location is not present, and the proxy can query a LIS which has location is not present, and the proxy can query a LIS which has
the location of the UA it MUST do so. If no location is present, the location of the UA it MUST do so. If no location is present,
and the proxy does not have access to a LIS which could provide and the proxy does not have access to a LIS which could provide
location, the proxy MUST supply a default location (See location, the proxy MUST supply a default location (See
Section 6.11). The location (in the signaling, obtained from a Section 6.11). The location (in the signaling, obtained from a
LIS, or default) MUST be used in a query to LoST with the service LIS, or default) MUST be used in a query to LoST with the service
URN received with the call. The resulting URI MUST be placed in URN received with the call. The resulting URI MUST be placed in
a Route header added to the call. a Route header added to the call.
3. The "inserted-by=" parameter in any Geolocation header received 3. The "inserted-by=" parameter in any Geolocation: header received
on the call MUST NOT be modified or deleted in transit. on the call MUST NOT be modified or deleted in transit.
4. The proxy SHOULD NOT modify any parameters in Geolocation headers 4. The proxy SHOULD NOT modify any parameters in Geolocation headers
received in the call. It MAY add a Geolocation header. Such an received in the call. It MAY add a Geolocation header. Such an
additional location SHOULD NOT be used for routing; the location additional location SHOULD NOT be used for routing; the location
provided by the UA should be used. provided by the UA should be used.
5. Either a P-Asserted-Identity [RFC3325] or an Identity header 5. Either a P-Asserted-Identity [RFC3325] or an Identity header
[RFC4474], or both, MUST be included to identify the sender. [RFC4474], or both, MUST be included to identify the sender.
SP-36 Unitialized devices MUST have a globally routable URI in a SP-33 Unitialized devices, like any device MUST have a globally
Contact header routable URI in a Contact: header.
SP-37 Unitialized devices SHOULD have a persistent URI in a SP-34 Unitialized devices SHOULD have a persistent URI in a
P-Asserted-Identity header P-Asserted-Identity: header if there is some way to assign such an
identifier to the device.
SP-38 During the course of an emergency call, devices and proxies SP-35 During the course of an emergency call, devices and proxies
MUST support REFER transactions and the Referred-by header [RFC3515]. MUST support REFER transactions and the Referred-by: header
[RFC3515].
SP-39 User agents and proxies MUST Support Session Timer [RFC4028] to SP-36 User agents and proxies MUST support Session Timer [RFC4028] to
guard against session corruption. guard against session corruption.
SP-40 User Agents and proxys MUST disable outgoing call features such SP-37 User Agents and proxys MUST disable outgoing call features such
as: as
o Call Waiting o Call Waiting
o Call Transfer o Call Transfer
o Three Way Call o Three Way Call
o Flash hold o Flash hold
o Outbound Call Blocking o Outbound Call Blocking
when an emergency call is established. Also see ED-72 in . when an emergency call is established. Also see ED-72 in Section 14.
(Section 14)
SP-41 The emergency dialstrings SHOULD NOT be permitted in Call SP-38 The emergency dialstrings SHOULD NOT be permitted in Call
Forward numbers or speed dial lists. Forward numbers or speed dial lists.
SP-42 The User Agent and Proxies SHOULD disable the following SP-39 The User Agent and Proxies SHOULD disable the following
incoming call features on call backs from the PSAP: incoming call features on call backs from the PSAP:
o Call Waiting o Call Waiting
o Do Not Disturb o Do Not Disturb
o Call Forward (all kinds) o Call Forward (all kinds)
A.3. Requirements of Access Networks A.3. Requirements of Access Network
AN-1 Elements MUST NOT convert (civic to geo or geo to civic) from AN-1 Elements MUST NOT convert (civic to geo or geo to civic) from
the form of location the determination mechanism supplied. the form of location the determination mechanism supplied.
AN-2 Any suitable location determination mechanism MAY be used. AN-2 Any suitable location determination mechanism MAY be used.
AN-3 Devices and/or access networks SHOULD support a manual method to AN-3 Devices, intermediate Devices and/or access networks SHOULD
"override" the location the access network determines. Where a civic support a manual method to "override" the location the access network
form of location is provided, all fields in the PIDF- LO [RFC4119] determines. Where a civic form of location is provided, all fields
and [I-D.ietf-geopriv-revised-civic-lo] MUST be able to be specified. in the PIDF-LO [RFC4119] and [RFC5139] MUST be able to be specified.
AN-4 Access networks supporting copper, fiber or other hard wired IP AN-4 Access networks supporting copper, fiber or other hard wired IP
packet service SHOULD support location configuration. If the network packet service SHOULD support location configuration. If the network
does not support location configuration, it MUST require every device does not support location configuration, it MUST require every device
that connects to the network to support end system measured location. that connects to the network to support end system measured location.
AN-5 Access networks providing wire database location information AN-5 Access networks and intermediate devices providing wire database
SHOULD provide interior location data where possible. It is location information SHOULD provide interior location data (building,
RECOMMENDED that interior location be provided when spaces exceed floor, room, cubicle) where possible. It is RECOMMENDED that
approximately 650 m2 interior location be provided when spaces exceed approximately 650
square meters.
AN-6 Access networks (including enterprise networks) which support AN-6 Access networks and intermediate devices (including enterprise
intermediate range wireless connections (typically 100m or less of networks) which support intermediate range wireless connections
range) and which do not support a more accurate location (typically 100m or less of range) and which do not support a more
determination mechanism such as triangulation, MUST support location accurate location determination mechanism such as triangulation, MUST
configuration which reports the location of the access point as the support location configuration where the location of the access point
location of the clients of that access point. is reflected as the location of the clients of that access point.
Where the access network provides location configuration,
intermediate devices MUST either be transparent to it, or provide an
interconnected client for the supported configuration mechanism and a
server for a configuration protocol supported by end devices upstream
of the intermediate device
AN-7 Devices that support endpoint measuring of location MUST have at AN-7 Devices that support endpoint measuring of location MUST have at
least a coarse location (<1km) capability at all times for routing of least a coarse location capability (typically <1km accuracy when not
calls. This mechanism MAY be a service provided by the access location hiding) at all times for routing of calls. This mechanism
network. MAY be a service provided by the access network.
AN-8 Access networks MAY provide network measured location AN-8 Access networks MAY provide network-measured location
determination. Wireless access network which do not support network determination. Wireless access network which do not support network
measured location MUST require all devices connected to the network measured location MUST require that all devices connected to the
have end-system measured location. Uncertainty of less than 100 m network have end-system measured location. Uncertainty of less than
with 95% confidence SHOULD be available for dispatch. 100 m with 95% confidence SHOULD be available for dispatch.
AN-9 Access networks that provide network measured location MUST have AN-9 Access networks that provide network measured location MUST have
at least a coarse location (<1km) capability at all times for routing at least a coarse location (typically <1km when not location hiding)
of calls. capability at all times for routing of calls.
AN-10 Access networks with range of <10M MUST provide a location to AN-10 Access networks with range of <10 meters MUST provide a
mobile devices connected to it. The location provided SHOULD be that location to mobile devices connected to it. The location provided
of the beacon location unless a more accurate mechanism is provided. SHOULD be that of the access point location unless a more accurate
mechanism is provided.
AN-11 The access network MUST support at least one of DHCP location AN-11 The access network MUST support at least one of: DHCP location
options, HELD or LLDP-MED. options, HELD or LLDP-MED.
AN-12 Where a router is employed between a LAN and WAN in a small AN-12 Where a router is employed between a LAN and WAN in a small
(less than approximately 650m2) area, the LAN MUST reflect the (less than approximately 650 square meters) area, the router MUST be
location provided by the WAN to the LAN. Where the area is larger, transparent to the location provided by the WAN to the LAN. This may
the LAN MUST have a location configuration mechanism meeting this mean the router must obtain location as a client from the WAN, and
BCP. supply an LCP server to the LAN with the location it obtains. Where
the area is larger, the LAN MUST have a location configuration
mechanism meeting this BCP.
AN-13 Access networks that support more than one LCP MUST reply with AN-13 Access networks that support more than one LCP MUST reply with
the same location information (within the limits of the data format the same location information (within the limits of the data format
for the specific LCP) for all LCPs it supports. for the specific LCP) for all LCPs it supports.
AN-14 Network administrators MUST take care in assigning IP addresses AN-14 Network administrators MUST take care in assigning IP addresses
such that VPN address assignments can be distinguished from local such that VPN address assignments can be distinguished from local
devices (by subnet choice, for example), and LISs SHOULD NOT attempt devices (by subnet choice, for example), and LISs SHOULD NOT attempt
to provide location to addresses that arrive via VPN connections to provide location to addresses that arrive via VPN connections
unless it can accurately determine the location for such addresses. unless it can accurately determine the location for such addresses.
AN-15 Placement of NAT devices SHOULD consider the effect of the NAT AN-15 Placement of NAT devices where an LCP uses IP address for an
on the LCP. identifier SHOULD consider the effect of the NAT on the LCP. The
address used to query the LIS MUST be able to correctly identify the
record in the LIS representing the location of the querying device
AN-16 It is RECOMMENDED that location determination not take longer AN-16 It is RECOMMENDED that location determination not take longer
than 250 ms to obtain routing location and systems SHOULD be designed than 250 ms to obtain routing location and systems SHOULD be designed
such that the typical response is under 100ms. However, as much as 3 such that the typical response is under 100 ms. However, as much as
seconds to obtain routing location MAY be tolerated if location 3 seconds to obtain routing location MAY be tolerated if location
accuracy can be substantially improved over what can be obtained in accuracy can be substantially improved over what can be obtained in
250 ms. 250 ms.
AN-17 Where the absolute location or the accuracy of location of the AN-17 Where the absolute location or the accuracy of location of the
endpoint may change between the time the call is received at the PSAP endpoint may change between the time the call is received at the PSAP
and the time dispatch is completed, location update mechanisms MUST and the time dispatch is completed, location update mechanisms MUST
be provided. be provided.
AN-18 mobile devices MUST be provided with a mechanism to get AN-18 Mobile devices MUST be provided with a mechanism to get
repeated location updates to track the motion of the device during repeated location updates to track the motion of the device during
the complete processing of the call. the complete processing of the call.
AN-19 The LIS SHOULD provide a location reference which permits a AN-19 The LIS SHOULD provide a location reference which permits a
subscription with appropriate filtering. subscription with appropriate filtering.
AN-20 For calls sent with location-by-reference, with a SIP or SIPS AN-20 For calls sent with location-by-reference, with a SIP or SIPS
scheme, the server resolving the reference MUST support a SUBSCRIBE scheme, the server resolving the reference MUST support a SUBSCRIBE
[RFC3118] to the presence event [RFC3856]. For other location-by- [RFC3265] to the presence event [RFC3856]. For other location-by-
reference schemes, a repeated location dereference by the PSAP MUST reference schemes, the PSAP will have to repeatedly dereference the
be supported. URI to determine if the device moved.
AN-21 Location validation of civic locations via LoST SHOULD be AN-21 A LIS should perform location validation of civic locations via
performed by the LIS before entering a location in its database. LoST before entering a location in its database.
AN-22 When the access network cannot determine the actual location of AN-22 When the access network cannot determine the actual location of
the caller, it MUST supply a default location. The default SHOULD be the caller, it MUST supply a default location. The default SHOULD be
chosen to be as close to the probable location of the device as the chosen to be as close to the probable location of the device as the
network can determine. network can determine. See [I-D.ietf-ecrit-framework]
AN-23 Default locations MUST be marked with method=Default and an AN-23 Default locations MUST be marked with method=Default and the
appropriate provided-by in the PIDF-LO. proxy MUST be identfied in provided-by element of the PIDF-LO.
AN-24 To prevent against spoofing of the DHCP server, elements AN-24 To prevent against spoofing of the DHCP server, elements
implementing DHCP for location configuration SHOULD use [RFC3118]. implementing DHCP for location configuration SHOULD use although the
difficulty in providing appropriate credentials is significant.
AN-25 Uninitialized devices SHOULD NOT be capable of placing an [RFC3118].
emergency call unless local regulations require it.
AN-26 Uninitialized devices that can place emergency calls MUST
supply location the same as a fully capable device would.
AN-27 https: MUST be specified when attempting to retrieve location AN-25 TLS MUST be specified when attempting to retrieve location
(configuration or dereferencing) with HELD. The use of [RFC4507] is (configuration or dereferencing) with HELD. The use of [RFC4507] is
RECOMMENDED to minimise the time to establish TLS sessions. RECOMMENDED to minimise the time to establish TLS sessions.
AN-26 If TLS session establishment fails, the location retrieveal
MUST be retried without TLS.
A.4. Requirements of Intermediate Devices
INT-1 Endpoints, Intermediate Devices and Service Providers MUST be
prepared to handle location represented in either civic or geo form.
INT-2 Elements MUST NOT convert (civic to geo or geo to civic) from
the form of location the determination mechanism supplied.
INT-3 Any suitable location determination mechanism MAY be used.
INT-4 Devices, intermediate Devices and/or access networks SHOULD
support a manual method to "override" the location the access network
determines. Where a civic form of location is provided, all fields
in the PIDF-LO [RFC4119] and [RFC5139] MUST be able to be specified.
INT-5 Access networks and intermediate devices providing wire
database location information SHOULD provide interior location data
(building, floor, room, cubicle) where possible. It is RECOMMENDED
that interior location be provided when spaces exceed approximately
650 square meters.
INT-6 Access networks and intermediate devices (including enterprise
networks) which support intermediate range wireless connections
(typically 100m or less of range) and which do not support a more
accurate location determination mechanism such as triangulation, MUST
support location configuration where the location of the access point
is reflected as the location of the clients of that access point.
Where the access network provides location configuration,
intermediate devices MUST either be transparent to it, or provide an
interconnected client for the supported configuration mechanism and a
server for a configuration protocol supported by end devices upstream
of the intermediate device
INT-7 Devices MAY support end-system measured location. Uncertainty
of less than 100 m with 95% confidence SHOULD be available for
dispatch.
INT-8 Devices that support endpoint measuring of location MUST have
at least a coarse location capability (typically <1km accuracy when
not location hiding) at all times for routing of calls. This
mechanism MAY be a service provided by the access network.
INT-9 Endpoints SHOULD do configure their own location.
INT-10 Where proxies provide location on behalf of endpoints, the the
service provider MUST ensure that either the end device is provided
with the local dial strings for its current location (where the end
device recognizes dial strings), or the service provider proxy MUST
detect the appropriate local dial strings at the time of the call.
INT-11 Devices SHOULD be able to accept and forward location by value
or by reference. An end device that receives location by reference
(and does not also get the corresponding value) MUST be able to
perform a dereference operation to obtain a value.
INT-12 Devices MUST support all of: DHCP location options [RFC4676]
and [RFC3825], HELD [I-D.ietf-geopriv-http-location-delivery] and
LLDP-MED [LLDP-MED].
INT-13 The access network MUST support at least one of: DHCP location
options, HELD or LLDP-MED.
INT-14 Where a router is employed between a LAN and WAN in a small
(less than approximately 650 square meters) area, the router MUST be
transparent to the location provided by the WAN to the LAN. This may
mean the router must obtain location as a client from the WAN, and
supply an LCP server to the LAN with the location it obtains. Where
the area is larger, the LAN MUST have a location configuration
mechanism meeting this BCP.
INT-15 Endpoints SHOULD try all LCPs supported by the device in any
order or in parallel. The first one that succeeds in supplying
location can be used.
INT-16 Access networks that support more than one LCP MUST reply with
the same location information (within the limits of the data format
for the specific LCP) for all LCPs it supports.
INT-17 When HELD is the LCP, the request MUST specify a value of
"emergencyRouting" for the "responseTime" parameter and use the
resulting location for routing. If a value for dispatch location
will be sent, another request with the "responseTime" parameter set
to "emergencyDispatch" must be completed, with the result sent for
dispatch purposes.
INT-18 Endpoints SHOULD obtain location immediately after obtaining
local network configuration information.When HELD is the LCP the
client MUST support a random back-off period (between 30 seconds and
300 seconds) for re-trying the HELD query, when no response is
received.
INT-19 If the device is configured to use DHCP for bootstrapping, it
MUST include both options for location acquisition (civic and
geodetic), the option for LIS discovery, and the option for LoST
discovery as defined in [RFC4676], [RFC3825],
[I-D.thomson-geopriv-lis-discovery] and
[I-D.ietf-ecrit-dhc-lost-discovery].
INT-20 If the device sends a DHCP INFORM message, it MUST include
both options for location acquisition (civic and geodetic), the
option for LIS discovery, and the option for LoST discovery as
defined in [RFC4676], [RFC3825], [I-D.thomson-geopriv-lis-discovery]
and [I-D.ietf-ecrit-dhc-lost-discovery].
INT-21 To minimize the effects of VPNs that do not allow split
tunneling VPNs, location configuration SHOULD be attempted before
such tunnels are established.
INT-22 Software which uses LCPs SHOULD locate and use the actual
hardware network interface rather than a VPN tunnel interface to
direct LCP requests to the LIS in the actual access network.
INT-23 For devices which are not expected to roam, refreshing
location on the order of once per day is RECOMMENDED.
INT-24 For devices which roam, refresh of location information SHOULD
be more frequent, with the frequency related to the mobility of the
device and the ability of the access network to support the refresh
operation. If the device can detect that it has moved, for example
when it changes access points, the device SHOULD refresh its
location.
INT-25 It is RECOMMENDED that location determination not take longer
than 250 ms to obtain routing location and systems SHOULD be designed
such that the typical response is under 100 ms. However, as much as
3 seconds to obtain routing location MAY be tolerated if location
accuracy can be substantially improved over what can be obtained in
250 ms.
Authors' Addresses Authors' Addresses
Brian Rosen Brian Rosen
NeuStar NeuStar
470 Conrad Dr. 470 Conrad Dr.
Mars, PA 16046 Mars, PA 16046
US US
Phone: +1 724 382 1051 Phone: +1 724 382 1051
Email: br@brianrosen.net Email: br@brianrosen.net
skipping to change at page 40, line 7 skipping to change at page 43, line 7
Cisco Systems Cisco Systems
3913 Treemont Circle 3913 Treemont Circle
Colleyville, TX 76034 Colleyville, TX 76034
US US
Phone: +1-817-271-3552 Phone: +1-817-271-3552
Email: jmpolk@cisco.com Email: jmpolk@cisco.com
Full Copyright Statement Full Copyright Statement
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
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