draft-ietf-speermint-architecture-09.txt   draft-ietf-speermint-architecture-10.txt 
Speermint Working Group A.Uzelac(Ed.)
Internet Draft Global Crossing
Intended status: Informational
Expires: May 2010
November 10, 2009
SPEERMINT Peering Architecture SPEERMINT A. Uzelac, Ed.
draft-ietf-speermint-architecture-09 Internet-Draft Global Crossing
Intended status: Informational R. Penno
Expires: September 10, 2010 Juniper Networks
M. Hammer
Cisco Systems
D. Malas
CableLabs
S. Khan
Comcast
H. Kaplan
Acme Packet
J. Livingood
Comcast
D. Schwartz
XConnect Global Networks
R. Shockey
Shockey Consulting
March 9, 2010
SPEERMINT Peering Architecture
draft-ietf-speermint-architecture-10
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Abstract
This document defines a peering architecture for the Session
Initation Protocol (SIP) [RFC3261], it's functional components and
interfaces. It also describes the steps necessary to establish a
session between two peering domains in the context of the functions
defined.
Status of this Memo Status of this Memo
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Abstract
This document defines the SPEERMINT peering architecture, its functional
components and peering interface functions. It also describes the steps taken
to establish a session between two peering domains in the context of the
functions defined.
Table of Contents Table of Contents
1. Introduction...................................................2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Reference SPEERMINT Architecture...............................4 2. Reference Architecture . . . . . . . . . . . . . . . . . . . . 4
3. Procedures of Inter-domain SSP Session Establishment...........4 3. Procedures of Inter-domain SSP Session Establishment . . . . . 5
3.1. Relationships between functions/elements..................5 4. Relationships between functions/elements . . . . . . . . . . . 6
4. Recommended SSP Procedures.....................................5 5. Recommended SSP Procedures . . . . . . . . . . . . . . . . . . 6
4.1. Originating SSP Procedures................................5 5.1. Originating SSP Procedures . . . . . . . . . . . . . . . . 7
4.1.1. The Look-Up Function (LUF)...........................5 5.1.1. The Look-Up Function (LUF) . . . . . . . . . . . . . . 7
4.1.1.1. Target Address Analysis.........................6 5.1.1.1. Target Address Analysis . . . . . . . . . . . . . 7
4.1.1.2. ENUM Lookup.....................................6 5.1.1.2. ENUM Lookup . . . . . . . . . . . . . . . . . . . 7
4.1.2. Location Routing Function (LRF)......................6 5.1.2. Location Routing Function (LRF) . . . . . . . . . . . 8
4.1.2.1. DNS Resolution..................................7 5.1.2.1. DNS resolution . . . . . . . . . . . . . . . . . . 8
4.1.2.2. Routing Table...................................7 5.1.2.2. Routing Table . . . . . . . . . . . . . . . . . . 8
4.1.2.3. LRF to LRF Routing..............................7 5.1.2.3. LRF to LRF Routing . . . . . . . . . . . . . . . . 8
4.1.3. The Signaling Path Border Element (SBE)..............7 5.1.3. Signaling Path Border Element (SBE) . . . . . . . . . 8
4.1.3.1. Establishing a Trusted Relationship.............8 5.1.4. Establishing a Trusted Relationship . . . . . . . . . 9
4.1.3.2. Sending the SIP request.........................8 5.1.4.1. IPSec . . . . . . . . . . . . . . . . . . . . . . 9
4.2. Target SSP Procedures.....................................8 5.1.4.2. Co-Location . . . . . . . . . . . . . . . . . . . 9
4.2.1. The Ingress Signaling Path Border Element (SBE)......8 5.1.4.3. Sending the SIP Request . . . . . . . . . . . . . 9
4.2.1.1. TLS.............................................8 5.2. Target SSP Procedures . . . . . . . . . . . . . . . . . . 9
4.2.1.2. Receive SIP requests............................9 5.2.1. The Ingress SBE . . . . . . . . . . . . . . . . . . . 10
4.3. Data Path Border Element (DBE)............................9 5.2.1.1. TLS . . . . . . . . . . . . . . . . . . . . . . . 10
5. Address space considerations...................................9 5.2.1.2. Receive SIP Requests . . . . . . . . . . . . . . . 10
6. Security Considerations........................................9 5.3. Data Path Border Element (DBE) . . . . . . . . . . . . . . 10
7. IANA Considerations...........................................10 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
8. Acknowledgments...............................................10 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
9. References....................................................11 8. Security Considerations . . . . . . . . . . . . . . . . . . . 11
9.1. Normative References.....................................11 9. Normative References . . . . . . . . . . . . . . . . . . . . . 11
9.2. Informative References...................................12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12
Author's Addresses...............................................13
1. Introduction
The objective of this document is to define a reference peering architecture in
the context of Session PEERing for Multimedia INTerconnect (SPEERMINT). In this
process, we define the peering reference architecture, its functional
components, and peering interface functions from the perspective of a SIP
Service provider's (SSP) network.
This architecture allows the interconnection of two SSPs in layer 5 peering as
defined in the SPEERMINT Requirements [14] and Terminology [13] documents.
Layer 3 peering is outside the scope of this document. Hence, the figures in 1. Introduction
this document do not show routers so that the focus is on Layer 5 protocol
aspects.
This document uses terminology defined in the SPEERMINT Terminology document The objective of this document is to define a reference peering
[13], so the reader should be familiar with all the terms defined there. architecture in the context of session peering for multimedia
interconnects. In this process, we define the peering reference
architecture, its functional components, and peering interface
functions from the perspective of a SIP Service provider's (SSP)
[RFC5486] network.
In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", This architecture allows the interconnection of two SSPs in layer 5
"SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are peering as defined in the SIP-based session peering requirements
to be interpreted as described in [RFC2119]. [I-D.ietf-speermint-requirements].
2. Reference SPEERMINT Architecture Layer 3 peering is outside the scope of this document. Hence, the
figures in this document focus on Layer 5 protocol functions and
elements.
Figure 2 depicts the SPEERMINT architecture and logical functions that form the This document uses terminology defined in the Session Peering for
peering between two SSPs. Multimedia Interconnect Terminology document [RFC5486].
--------------- --------------- 2. Reference Architecture
/ \ / \
| +--LUF-+ | +------+ | +--LUF-+ |
| |->| | | | ENUM | | | |<-| |
| | | +------------>| TN DB|<------------+ | | |
| | | | | +------+ | | | | |
| | +------+ | | +------+ | |
| | | | | |
| | +--LRF-+ | +--------+ | +--LRF-+ | |
| |->| | | | DNS | | | |<-| |
| | | +----------->|IP Addrs|<-----------+ | | |
| | | | | +--------+ | | | | |
| | +------+ | | +------+ | |
| | | | | |
| | | | | |
| | +-------+ +-------+ | |
| ----------->| | | |<----------- |
| | SBE |<------------>| SBE | |
| | | | | |
| +-------+ +-------+ |
| SSP1 | | SSP2 |
| +-------+ +-------+ |
| | | | | |
| | DBE |<------------>| DBE | |
| | | | | |
| +-------+ +-------+ |
\ / \ /
--------------- ---------------
Figure 1: Reference SPEERMINT Architecture
For further details on the elements and functions described in this figure, Figure 1 depicts the architecture and logical functions that form
please refer to [RFC 5486]. peering between two SSPs. The terms used in the diagram are expanded
here for reference:
3. Procedures of Inter-domain SSP Session Establishment o SBE - Signaling Path Border Element is described in Section 5.1.3
This document assumes that in order for a session to be established from a UA o LUF - Look-up Function is described in Section 5.1.1
in the Originating SSP's network to an UA in the Target SSP's network the
following steps are taken:
1. Determine the target SSP via the LUF. o LRF - Location Routing Function is described in Section 5.1.2
a. If the target address represents an intra-SSP resource, the o SF - Signaling Function is defined in [RFC5486]
behavior is out-of-scope with respect to this draft.
2. Determine the address of the SF of the target SSP via the LRF. o SIP - Session Initiation Protocol is defined in [RFC3261]
3. Establish the session o DBE - Data Path Border Element is described in Section 5.3
4. Exchange the media, which could include voice, video, tec, etc. o DNS - Domain Name Service is described in Section 5.1.2.1
5. End the session (BYE) o ENUM - E.164 Number Mapping is described in Section 5.1.1.2
The originating SSP would likely perform steps 1-4, and the target SSP would o FQDN - Fully Qualified Domain Name
likely perform steps 4-5.
In the case the target SSP changes, then steps 1-4 would be repeated. This is o TN DB - Telephone Number Database
reflected in Figure 2 that shows the target SSP with its own peering functions. o IP - IPv4/v6 Address
3.1. Relationships between functions/elements o RTP - Real-time Transport Protocol is defined in [RFC3550]
- An SBE can contain a SF function. +=============++ ++==============+
- An SF can perform LUF and LRF functions. || ||
- As an additional consideration, a Session Border Controller [SBC RFC], can +-----------+ +-----------+
contain an SF, SBE and DBE, and may perform the LUF and LRF functions. | SBE | | SBE |
- The following functions can communicate as follows, depending upon various | +-----+ | SIP +-----+ | +-----+ |
real-world implementations: | | LUF |<-|------>|ENUM | | | LUF | |
o SF can communicate with LUF, LRF, SBE and SF | +-----+ | ENUM |TN DB| | +-----+ |
o LUF can communicator with SF and SBE SIP | | +-----+ | |
o LRF can communicate with SF and SBE ------>| +-----+ | DNS +-----+ | +-----+ |
| | LRF |<-|------>|FQDN | | | LRF | |
| +-----+ | |IP | | +-----+ |
| +-----+ | SIP +-----+ | +-----+ |
| | SF |<-|----------------|->| SF | |
| +-----+ | | +-----+ |
+-----------+ +-----------+
|| ||
+-----------+ +-----------+
RTP | DBE | RTP | DBE |
------>| |--------------->| |
+-----------+ +-----------+
|| ||
SSP1 Network || || SSP2 Network
+=============++ ++=============+
4. Recommended SSP Procedures Figure 1
This section describes the functions in more detail and provides some For further details on the elements and functions described in this
recommendations on the role they would play in a SIP call in a Layer 5 peering figure, please refer to [RFC5486].
scenario.
Some of the information in the section is taken from [14] and is put here for 3. Procedures of Inter-domain SSP Session Establishment
continuity purposes.
4.1. Originating SSP Procedures This document assumes that in order for a session to be established
from a User Agent (UA) in the Originating SSP's network to a UA in
the Target SSP's network the following steps are taken:
4.1.1. The Look-Up Function (LUF) 1. Determine the target SSP via the LUF. (Note: If the target
address represents a resource within the originating SSP, the
behavior is out-of-scope with respect to this draft.)
Purpose is to determine the SF of the target domain of a given request and 2. Determine the address of the SF of the target SSP via the LRF.
optionally develop Session Establishment Data.
4.1.1.1. Target Address Analysis 3. Establish the session
When the originating SSP receives a request to communicate, it analyzes the 4. Exchange the media, which could include voice, video, text, etc.
target URI to determine whether the call needs to be routed internal or
external to its network. The analysis method is internal to the SSP; thus,
outside the scope of SPEERMINT.
If the target address does not represent a resource inside the originating 5. End the session
SSP's administrative domain or federation of domains, then the originating SSP
performs a Lookup Function (LUF) to determine a target address, and then is
resolves the call routing data by using the Location routing Function (LRF).
For example, if the request to communicate is for an im: or pres: URI type, the The originating SSP would likely perform steps 1-4, and the target
originating SSP follows the procedures in [8]. If the highest priority SSP would likely perform steps 4-5.
supported URI scheme is sip: or sips: the originating SSP skips to SIP DNS
resolution in Section 5.1.3. Likewise, if the target address is already a sip:
or sips: URI in an external domain, the originating SSP skips to SIP DNS
resolution in Section 4.1.2.1.
If the target address corresponds to a specific E.164 address, the SSP may need If the target SSP is also an indirect peer, then steps 1-4 may be
to perform some form of number plan mapping according to local policy. For repeated. This is reflected in Figure 1 that shows the target SSP
example, in the United States, a dial string beginning "011 44" could be with its own peering functions.
converted to "+44", or in the United Kingdom "00 1" could be converted to "+1".
Once the SSP has an E.164 address, it can use ENUM.
4.1.1.2. ENUM Lookup 4. Relationships between functions/elements
If an external E.164 address is the target, the originating SSP consults the o An SBE can contain a SF function.
public "User ENUM" rooted at e164.arpa, according to the procedures described
in RFC 3761. The SSP must query for the "E2U+sip" enumservice as described in
RFC 3764 [11], but MAY check for other enumservices. The originating SSP MAY
consult a cache or alternate representation of the ENUM data rather than actual
DNS queries. Also, the SSP may skip actual DNS queries if the originating SSP
is sure that the target address country code is not represented in e164.arpa.
If a sip: or sips: URI is chosen the SSP skips to Section 5.1.6.
If an im: or pres: URI is chosen for based on an "E2U+im" [8] or "E2U+pres" [9] o An SF can perform LUF and LRF functions.
enumserver, the SSP follows the procedures for resolving these URIs to URIs for
specific protocols such a SIP or XMPP as described in the previous section.
4.1.2. Location Routing Function (LRF) o As an additional consideration, in current Session Border
Controller (SBC) implementations, an SBC can contain an SF, SBE
and DBE, and may perform the LUF and LRF functions.
The LRF of an Originating SSP analyzes target address and target domain o The following functions can communicate as follows, depending upon
identified by the LUF, and discovers the next hop signaling function (SF) in a various real-world implementations:
peering relationship. The resource to determine the SF of the target domain
might be provided by a third-party as in the assisted-peering case. The
following sections define mechanisms which may be used by the LRF. These are
not in any particular order and, importantly, not all of them may be used.
4.1.2.1. DNS Resolution * SF can communicate with LUF, LRF and another SF
The originating SSP uses the procedures in RFC 3263 [4] Section 4 to determine * LUF can communicate with SF
how to contact the receiving SSP. To summarize the RFC 3263 procedure: unless
these are explicitly encoded in the target URI, a transport is chosen using
NAPTR records, a port is chosen using SRV records, and an address is chosen
using A or AAAA records.
When communicating with another SSP, entities compliant to this document should * LRF can communicate with SF
select a TLS-protected transport for communication from the originating SSP to
the receiving SSP if available.
4.1.2.2. Routing Table 5. Recommended SSP Procedures
If there are no End User ENUM records and the Originating SSP cannot discover This section describes the functions in more detail and provides some
the carrier-of-record or if the Originating SSP cannot reach the carrier-of- recommendations on the role they would play in an example SIP
record via SIP peering, the Originating SSP may deliver the call to the PSTN or telephony call scenario.
reject it. Note that the originating SSP may forward the call to another SSP
for PSTN gateway termination by prior arrangement using the routing table.
If so, the originating SSP rewrites the Request-URI to address the gateway Some of the information in the section is taken from
resource in the target SSP's domain and MAY forward the request on to that SSP [I-D.ietf-speermint-requirements] and is put here for continuity
using the procedures described in the remainder of these steps. purposes.
4.1.2.3. LRF to LRF Routing 5.1. Originating SSP Procedures
Communications between the LRF of two interconnecting SSPs may use DNS or 5.1.1. The Look-Up Function (LUF)
statically provisioned IP Addresses for reachability. Other inputs to
determine the path may be code-based routing, method-based routing, Time of
day, least cost and/or source-based routing.
4.1.3. The Signaling Path Border Element (SBE) Purpose is to determine the SF of the target domain of a given
request and optionally develop Session Establishment Data.
The purpose of signaling function is to perform routing of SIP messages as well 5.1.1.1. Target Address Analysis
as optionally implement security and policies on SIP messages, and to assist in
discovery/exchange of parameters to be used by the Media Function (MF).
The signaling function performs the routing of SIP messages. The optional When the originating SSP receives a SIP request, it analyzes the
termination and re-initiation of calls may be performed by the signaling path target URI to determine whether the call needs to be routed internal
Session Border Element (SBE), or other signaling elements. or external to its network.
Optionally, a SF may perform additional functions such as Session Admission If the target address does not represent a resource inside the
Control, SIP Denial of Service protection, SIP Topology Hiding, SIP header originating SSP's administrative domain, then the originating SSP
normalization, SIP security, privacy, and encryption. performs a Lookup (LUF) to determine the target domain, and then it
resolves the call routing data by using Location Routing (LRF).
The SF of a SBE can also process SDP payloads for media information such as For example, if the request to communicate is for an im: or pres: URI
media type, bandwidth, and type of codec; then, communicate this information to type, the originating SSP follows the procedures in [RFC3861]. If
the media function. Signaling function may optionally communicate with the the highest priority supported URI scheme is sip: or sips: the
network to pass Layer 3 related policies [10] originating SSP skips to SIP DNS resolution. Likewise, if the target
address is already a sip: or sips: URI in an external domain, the
originating SSP skips to SIP DNS resolution in Section 5.1.2.1
4.1.3.1. Establishing a Trusted Relationship If the target address corresponds to a specific E.164 address, the
SSP may need to perform some form of number plan mapping according to
local policy. For example, in the United States, a dial string
beginning "011 44" could be converted to "+44", or in the United
Kingdom "00 1" could be converted to "+1". Once the SSP has an E.164
address, it can use ENUM.
Depending on the security needs and trust relationships between SSPs, different 5.1.1.2. ENUM Lookup
security mechanism can be used to establish SIP calls. These are discussed in
the following subsections.
4.1.3.1.1. IPSec If an external E.164 address is the target, the originating SSP
consults a private or public ENUM server, according to the procedures
described in [RFC3761]. The SSP must query for the "E2U+sip"
enumservice as described in [RFC3764], but MAY check for other
enumservices. The originating SSP MAY consult a cache or alternate
representation of the ENUM data rather than actual DNS queries.
Also, the SSP may skip actual DNS queries if the target domain is
represented as an IPv4/v6 address.
In certain deployments the use of IPSec between the signaling functions of the If an im: or pres: URI is chosen for based on an "E2U+im" [RFC3861]
originating and terminating domains can be used as a security mechanism instead or "E2U+pres" [RFC3953] enumserver, the SSP follows the procedures
of TLS. for resolving these URIs to URIs for specific protocols such a SIP or
XMPP.
4.1.3.1.2. Co-Location 5.1.2. Location Routing Function (LRF)
In this scenario the SFs are co-located in a physically secure location and/or The LRF of an Originating SSP analyzes the target address and target
are members of a segregated network. In this case messages between the domain identified by the LUF, and discovers the next hop signaling
originating and terminating SSPs would be sent as clear text. function (SF) in a peering relationship. The resource to determine
the SF of the target domain might be provided by a third-party as in
the indirect peering case. The following sections define mechanisms
which may be used by the LRF. These are not in any particular order
and, importantly, not all of them may be used.
4.1.3.2. Sending the SIP request 5.1.2.1. DNS resolution
Once a trust relationship between the peers is established, the originating SSP The originating SSP uses the procedures in [RFC3263] to determine how
sends the request. to contact the target SSP. To summarize the RFC 3263 procedure:
unless these are explicitly encoded in the target URI, a transport is
chosen using Naming Authority Pointer (NAPTR) records, a port is
chosen using SRV records, and an address is chosen using A or AAAA
records.
4.2. Target SSP Procedures When communicating with another SSP, entities compliant to this
document should select a TLS-protected transport for communication
from the Originating SSP to the target SSP if available.
4.2.1. The Ingress Signaling Path Border Element (SBE) 5.1.2.2. Routing Table
4.2.1.1. TLS If there are no End User ENUM records and the Originating SSP cannot
discover the carrier-of-record or if the Originating SSP cannot reach
the carrier-of-record via SIP peering, the Originating SSP may
deliver the call to the PSTN or reject it. Note that the originating
SSP may forward the call to another SSP for PSTN gateway termination
by prior arrangement using the routing table.
When the receiving SSP receives a TLS client hello, it responds with its If so, the originating SSP rewrites the Request-URI to address the
certificate. The Target SSP certificate should be valid and rooted in a well- gateway resource in the target SSP's domain and MAY forward the
known certificate authority. The procedures to authenticate the SSP's request on to that SSP using the procedures described in the
originating domain are specified in [24]. remainder of these steps.
The SF of the Target SSP verifies that the Identity header is valid, 5.1.2.3. LRF to LRF Routing
corresponds to the message, corresponds to the Identity-Info header, and that
the domain in the From header corresponds to one of the domains in the TLS
client certificate.
4.2.1.2. Receive SIP requests Communication between the LRF of two interconnecting SSPs may use DNS
or statically provisioned IP Addresses for reachability. Other
inputs to determine the path may be code-based routing, method-based
routing, Time of day, least cost and/or source-based routing.
Once a trust relationship is established, the Target SSP is prepared to receive 5.1.3. Signaling Path Border Element (SBE)
incoming SIP requests. For new requests (dialog forming or not) the receiving
SSP verifies if the target (request-URI) is a domain that for which it is
responsible. For these requests, there should be no remaining Route header
field values. For in-dialog requests, the receiving SSP can verify that it
corresponds to the top-most Route header field value.
The receiving SSP may reject incoming requests due to local policy. When a The purpose of signaling path border element is to perform routing of
request is rejected because the originating SSP is not authorized to peer, the SIP messages as well as optionally implement security and policies on
receiving SSP should respond with a 403 response with the reason phrase SIP messages, and to assist in discovery/exchange of parameters to be
"Unsupported Peer". used by the Media Function (MF).
4.3. Data Path Border Element (DBE) The signaling function performs the routing of SIP messages. The
optional termination and re-initiation of calls may be performed by
the signaling path Session Border Element (SBE), or other signaling
elements.
The purpose of the DBE [RFC 5486] is to perform media related functions such as Optionally, the SF of a SBE may perform additional functions such as
media transcoding and media security implementation between two SSPs. Session Admission Control, SIP Denial of Service protection, SIP
Topology Hiding, SIP header normalization, SIP security, privacy, and
encryption.
An Example of this is to transform a voice payload from one codec (e.g., G.711) The SF of a SBE can also process SDP payloads for media information
to another (e.g., EvRC). Additionally, the MF may perform media relaying, such as media type, bandwidth, and type of codec; then, communicate
media security, privacy, and encryption. this information to the media function. Signaling function may
optionally communicate with the network to pass Layer 3 related
policies.
5. Address space considerations 5.1.4. Establishing a Trusted Relationship
Peering must occur in a common IP address space, which is defined by the Depending on the security needs and trust relationships between SSPs,
federation, which may be entirely on the public Internet, or some private different security mechanism can be used to establish SIP calls.
address space. The origination or termination networks may or may not entirely These are discussed in the following subsections.
be in the same address space. If they are not, then a network address
translation (NAT) or similar may be needed before the signaling or media is
presented correctly to the federation. The only requirement is that all
associated entities across the peering interface are reachable.
6. Security Considerations 5.1.4.1. IPSec
In all cases, cryptographic-based security should be maintained as an optional In certain deployments the use of IPSec between the signaling
requirement between peering providers conditioned on the presence or absence of functions of the originating and terminating domains can be used as a
underlying physical security of SSP connections, e.g. within the same secure security mechanism instead of TLS.
physical building.
In order to maintain a consistent approach, unique and specialized security 5.1.4.2. Co-Location
requirements common for the majority of peering relationships, should be
standardized within the IETF. These standardized methods may enable
capabilities such as dynamic peering relationships across publicly maintained
interconnections.
7. IANA Considerations In this scenario the SFs are co-located in a physically secure
location and/or are members of a segregated network. In this case
messages between the originating and terminating SSPs would be sent
as clear text.
There are no IANA considerations at this time. 5.1.4.3. Sending the SIP Request
8. Acknowledgments Once a trust relationship between the peers is established, the
originating SSP sends the request.
The working group thanks Sohel Khan for his initial architecture 5.2. Target SSP Procedures
draft that helped to initiate work on this draft. 5.2.1. The Ingress SBE
A significant portion of this draft is taken from [14] with 5.2.1.1. TLS
permission from the author R. Mahy. The other important contributor
is Otmar Lendl. Special thanks to Jim McEachern for detailed comments and
feedback.
9. References When the target SSP receives a TLS client hello, it responds with its
certificate. The Originating SSP certificate should be valid and
rooted in a well-known certificate authority. The procedures to
authenticate the SSP's originating domain are specified in
[I-D.ietf-sip-domain-certs].
9.1. Normative References The SF of the Target SSP verifies that the Identity header is valid,
corresponds to the message, corresponds to the Identity-Info header,
and that the domain in the From header corresponds to one of the
domains in the TLS client certificate.
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", 5.2.1.2. Receive SIP Requests
BCP 14, RFC 2119, March 1997.
[2] Mealling, M. and R. Daniel, "The Naming Authority Pointer (NAPTR) DNS Once a trust relationship is established, the Target SSP is prepared
Resource Record", RFC 2915, September 2000. to receive incoming SIP requests. For new requests (dialog forming
or not) the receiving SSP verifies if the target (request-URI) is a
domain for which it is responsible. For these requests, there should
be no remaining Route header field values. For in-dialog requests,
the receiving SSP can verify that it corresponds to the top-most
Route header field value.
[3] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, The receiving SSP may reject incoming requests due to local policy.
J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation When a request is rejected because the originating SSP is not
Protocol", RFC 3261, June 2002. authorized to peer, the receiving SSP should respond with a 403
response with the reason phrase "Unsupported Peer".
[4] Rosenberg, J. and H. Schulzrinne, "Session Initiation Protocol (SIP): 5.3. Data Path Border Element (DBE)
Locating SIP Servers", RFC 3263, June 2002.
[5] Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J., and T. The purpose of the DBE [RFC5486] is to perform media related
Wright, "Transport Layer Security (TLS) Extensions", RFC 4366, April functions such as media transcoding and media security implementation
2006. between two SSPs.
[6] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A An Example of this is to transform a voice payload from one codec
Transport Protocol for Real-Time Applications", STD 64, RFC 3550, July (e.g., G.711) to another (e.g., Enhanced Variable Rate Codec (EvRC)).
2003. Additionally, the MF may perform media relaying, media security,
privacy, and encryption.
[7] Peterson, J., Liu, H., Yu, J., and B. Campbell, "Using E.164 numbers 6. Acknowledgments
with the Session Initiation Protocol (SIP)", RFC 3824, June 2004.
[8] Peterson, J., "Address Resolution for Instant Messaging and The working group thanks Sohel Khan for his initial architecture
Presence",RFC 3861, August 2004. draft that helped to initiate work on this draft.
[9] Peterson, J., "Telephone Number Mapping (ENUM) Service Registration for Other contributors include Rohan Mahy, Otmar Lendl, Jim McEachern and
Presence Services", RFC 3953, January 2005. John Elwell for detailed comments and feedback.
[10] ETSI TS 102 333: " Telecommunications and Internet converged Services 7. IANA Considerations
and Protocols for Advanced Networking (TISPAN); Gate control protocol".
[11] Peterson, J., "enumservice registration for Session Initiation Protocol This memo includes no request to IANA.
(SIP) Addresses-of-Record", RFC 3764, April 2004.
[12] Livingood, J. and R. Shockey, "IANA Registration for an 8. Security Considerations
Enumservice Containing PSTN Signaling Information", RFC 4769, November
2006.
9.2. Informative References In all cases, cryptographic-based security should be maintained as an
optional requirement between peering providers conditioned on the
presence or absence of underlying physical security of SSP
connections, e.g. within the same secure physical building.
[13] Malas, D., "SPEERMINT Terminology", draft-ietf-speermint-terminology-16 In order to maintain a consistent approach, unique and specialized
(work in progress), February 2008. security requirements common for the majority of peering
relationships, should be standardized within the IETF. These
standardized methods may enable capabilities such as dynamic peering
relationships across publicly maintained interconnections.
[14] Mule, J-F., "SPEERMINT Requirements for SIP-based VoIP Interconnection", 9. Normative References
draft-ietf-speermint-requirements-04.txt, February 2008.
[15] Mahy, R., "A Minimalist Approach to Direct Peering", draft- [I-D.ietf-sip-domain-certs]
mahy-speermint-direct-peering-02.txt, July 2007. Gurbani, V., Lawrence, S., and B. Laboratories, "Domain
Certificates in the Session Initiation Protocol (SIP)",
draft-ietf-sip-domain-certs-05 (work in progress),
March 2010.
[16] Penno, R., et al., "SPEERMINT Routing Architecture Message [I-D.ietf-speermint-requirements]
Flows", draft-ietf-speermint-flows-02.txt", April 2007. Mule, J., "SPEERMINT Requirements for SIP-based Session
Peering", draft-ietf-speermint-requirements-09 (work in
progress), October 2009.
[17] Houri, A., et al., "RTC Provisioning Requirements", draft- [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
houri-speermint-rtc-provisioning-reqs-00.txt, June, 2006. A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261,
June 2002.
[18] Habler, M., et al., "A Federation based VOIP Peering [RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation
Architecture", draft-lendl-speermint-federations-03.txt, September 2006. Protocol (SIP): Locating SIP Servers", RFC 3263,
June 2002.
[19] Mahy, R., "A Telephone Number Mapping (ENUM) Service [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Registration for Instant Messaging (IM) Services", draft-ietf- Jacobson, "RTP: A Transport Protocol for Real-Time
enum-im-service-03 (work in progress), March 2006. Applications", STD 64, RFC 3550, July 2003.
[20] Haberler, M. and R. Stastny, "Combined User and Carrier ENUM in the [RFC3761] Faltstrom, P. and M. Mealling, "The E.164 to Uniform
e164.arpa tree", draft-haberler-carrier-enum-03 (work in progress), Resource Identifiers (URI) Dynamic Delegation Discovery
March 2006. System (DDDS) Application (ENUM)", RFC 3761, April 2004.
[21] Penno, R., Malas D., and Melampy, P., "A Session Initiation [RFC3764] Peterson, J., "enumservice registration for Session
Protocol (SIP) Event package for Peering", draft-penno-sipping-peering- Initiation Protocol (SIP) Addresses-of-Record", RFC 3764,
package-00 (work in progress), September 2006. April 2004.
[22] Hollander, D., Bray, T., and A. Layman, "Namespaces in XML", W3C REC [RFC3861] Peterson, J., "Address Resolution for Instant Messaging
REC-xml-names-19990114, January 1999. and Presence", RFC 3861, August 2004.
[23] Burger, E (Ed.), "A Mechanism for Content Indirection in [RFC3953] Peterson, J., "Telephone Number Mapping (ENUM) Service
Session Initiation Protocol (SIP) Messages", RFC 4483, May 2006 Registration for Presence Services", RFC 3953,
January 2005.
[24] Gurbani, V., Lawrence, S., and B. Laboratories, "Domain Certificates in [RFC5486] Malas, D. and D. Meyer, "Session Peering for Multimedia
the Session Initiation Protocol (SIP)", draft-ietf-sip-domain-certs-00 Interconnect (SPEERMINT) Terminology", RFC 5486,
(work in progress), November 2007. March 2009.
Author's Addresses Authors' Addresses
Adam Uzelac Adam Uzelac (editor)
Global Crossing Global Crossing
Rochester, NY - USA Rochester, NY
US
Email: adam.uzelac@globalcrossing.com Email: adam.uzelac@globalcrossing.com
Reinaldo Penno Reinadlo Penno
Juniper Networks Juniper Networks
Sunnyvale, CA - USA Sunnyvale, CA
US
Email: rpenno@juniper.net Email: rpenno@juniper.net
Mike Hammer Mike Hammer
Cisco Systems Cisco Systems
Herndon, VA - USA Herndon, VA
Email: mhammer@cisco.com US
Sohel Khan, Ph.D.
Comcast Cable Communications
USA
Email: sohel_khan@cable.comcast.com
Email: mhammer@cisco.com
Daryl Malas Daryl Malas
CableLabs CableLabs
Louisville, CO - USA Louisville, CO
US
Email: d.malas@cablelabs.com Email: d.malas@cablelabs.com
Sohel Khan
Comcast
Philadelphia, PA
US
Email: sohel_khan@cable.comcast.com
Hadriel Kaplan Hadriel Kaplan
Acme Packet Acme Packet
Burlington, MA
US
Email: hkaplan@acmepacket.com Email: hkaplan@acmepacket.com
Jason Livingood Jason Livingood
Comcast Comcast
Email: Jason_livingood@cable.comcast.com Philadelphia, PA
US
Email: Jason_Livingood@cable.comcast.com
David Schwartz David Schwartz
Kayote Systems XConnect Global Networks
Email: david.schwartz@kayote.com Jerusalem
Israel
Email: dschwartz@xconnnect.net
Richard Shockey
Shockey Consulting
US
Rich Shockey
Unaffiliated
Email: Richard@shockey.us Email: Richard@shockey.us
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