draft-ietf-iptel-tgrep-04.txt   draft-ietf-iptel-tgrep-05.txt 
IPTEL Working Group Manjunath Bangalore, Cisco Systems
Internet Draft Rajneesh Kumar, Cisco Systems IPTEL Working Group Manjunath Bangalore, Cisco Systems Inc.
draft-ietf-iptel-tgrep-04.txt Jonathan Rosenberg, dynamicsoft Internet Draft Rajneesh Kumar, Cisco Systems Inc.
October 21, 2004 Hussein Salama, Cisco Systems draft-ietf-iptel-tgrep-05.txt Jonathan Rosenberg, Cisco Systems Inc.
Expiration Date: April 21, 2005 Dhaval N. Shah, Cisco Systems February 2005 Hussein Salama, Cisco Systems Inc.
Expiration Date: August 2005 Dhaval Shah, Cisco Systems Inc.
A Telephony Gateway REgistration Protocol (TGREP) A Telephony Gateway REgistration Protocol (TGREP)
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is subject to all provisions
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RFC 3668. RFC 3668.
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved. Copyright (C) The Internet Society (2005).
Abstract Abstract
This document describes the Telephony Gateway Registration Protocol This document describes the Telephony Gateway Registration Protocol
(TGREP) for registration of telephony prefixes supported by telephony (TGREP) for registration of telephony prefixes supported by telephony
gateways and soft switches. The registration mechanism can also be gateways and soft switches. The registration mechanism can also be
used to export resource information. The prefix and resource used to export resource information. The prefix and resource
information can then be passed on to a TRIP Location Server, which in information can then be passed on to a Telephony Routing over IP
turn can propogate that routing information within and between (TRIP) Location Server, which in turn can propagate that routing
internet telephony administrative domains (ITAD). TGREP shares a lot information within and between internet telephony administrative
of similarites with the TRIP Protocol. It has similar procedures and domains (ITAD). TGREP shares a lot of similarities with the TRIP
Finite State Machine for session establishment. It also shares the Protocol. It has similar procedures and Finite State Machine for
same format for messages and a subset of attributes with TRIP. session establishment. It also shares the same format for messages
and a subset of attributes with TRIP.
TGREP entities are valid trip implementations, but they do only a
subset of what they otherwise could. In particular, a gateway is
always in Send mode, the LS peering with it is always in Receive
mode.
Table of Contents
1 Terminology and Definitions .............................. 4
2 Introduction ............................................. 4
3 TGREP: Overview of operation ............................. 6
4 TGREP Attributes ......................................... 7
4.1 TotalCircuitCapacity Attribute ........................... 7
4.2 AvailableCircuits Attribute .............................. 9
4.3 CallSuccess Attribute .................................... 10
4.4 Prefix Attributes ........................................ 12
4.5 TrunkGroup Attribute ..................................... 13
4.6 Carrier Attribute ........................................ 15
4.7 TrunkGroup and Carrier Address Families .................. 16
4.8 Gateway Operation ........................................ 19
4.9 LS/Proxy Behavior ........................................ 21
5 Security Considerations .................................. 26
6 IANA Considerations ...................................... 27
6.1 Attribute Codes .......................................... 27
6.2 Address Family Codes ..................................... 27
7 Change history ........................................... 28
7.1 Changes since draft-ietf-iptel-tgrep-03.txt .............. 28
7.2 Changes since draft-ietf-iptel-tgrep-02.txt .............. 28
7.3 Changes since draft-ietf-iptel-tgrep-01.txt .............. 28
7.4 Changes since draft-ietf-iptel-tgrep-00.txt .............. 28
7.5 Changes since draft-ietf-iptel-trip-gw-00.txt ............ 29
7.6 Changes since -03 ........................................ 29
7.7 Changes since -02 ........................................ 29
7.8 Changes since -01 ........................................ 30
7.9 Changes since -00 ........................................ 30
8 Acknowledgments .......................................... 30
9 References ............................................... 30
9.1 Normative References ..................................... 30
9.2 Informative References ................................... 31
Authors' Addresses ....................................... 31
Intellectual Property Statement .......................... 32
Disclaimer of Validity ................................... 33
Copyright Statement ...................................... 33
Acknowledgment ........................................... 33
1. Terminology and Definitions 1. Terminology and Definitions
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 RFC 2119 [1]. document are to be interpreted as described in RFC 2119 [1].
Some other useful definitions are: Some other useful definitions are:
Circuit: A circuit is a discrete (specific) path between two or more Circuit: A circuit is a discrete (specific) path between two or more
skipping to change at page 2, line 37 skipping to change at page 4, line 32
TrunkGroup: A set of trunks, traffic engineered as a unit, for the TrunkGroup: A set of trunks, traffic engineered as a unit, for the
establishment of connections within or between switching systems in establishment of connections within or between switching systems in
which all of the paths are interchangeable except where subgrouped. which all of the paths are interchangeable except where subgrouped.
Carrier: A company offering telephone and data communications between Carrier: A company offering telephone and data communications between
points (end-users and/or exchanges). points (end-users and/or exchanges).
2. Introduction 2. Introduction
It is assumed that reader of this has already gone through TRIP [4].
In typical VoIP networks, Internet Telephony Administrative Domains In typical VoIP networks, Internet Telephony Administrative Domains
(ITADs) will deploy numerous gateways for the purposes of (ITADs) will deploy numerous gateways for the purposes of
geographical diversity, capacity, and redundancy. When a call arrives geographical diversity, capacity, and redundancy. When a call arrives
at the domain, it must be routed to one of those gateways. at the domain, it must be routed to one of those gateways.
Frequently, an ITAD will break their network into geographic POPs, Frequently, an ITAD will break their network into geographic Points
with each POP containing some number of gateways, and a proxy server of Presence (POP), with each POP containing some number of gateways,
element that fronts those gateways. The proxy server is responsible and a proxy server element that fronts those gateways. The proxy
for managing the access to the POP, and also for determining which of server is responsible for managing the access to the POP, and also
the gateways will receive any given call that arrives at the POP. for determining which of the gateways will receive any given call
that arrives at the POP. In conjunction with the proxy server that
routes the call signaling, there are two TRIP Speaker components, the
"Ingress LS" and the "Egress LS". The Ingress LS maintains TGREP
peering relationship with one or more gateways. The routing
information received from the gateways are further injected into the
Egress LS, which in turn disseminates into the rest of the network on
TRIP.
This configuration is depicted graphically in Figure 1. This configuration is depicted graphically in Figure 1.
+---------+ +---------+
| | | |
| GW | | GW |
-> +---------+ > +---------+
// //
// //
// +---------+ // +---------+
// | | // | |
// | GW | +-------------------------+ // | GW |
// +---------+ | | // +---------+
// | +-------------+ |/
+----------+ // TO PSTN | | | | TO PSTN
| | / +---------+ | | Routing | | +---------+
| Routing | ---------------> | | -----> | | Proxy | | -------> | | ----->
-------->| Proxy | | GW | ---> | | |---- | GW |
|+---+-----+ +-----+----+ | +---------+
|| | | | |
|| <+-+ | |--
||Egress LS| |Ingress LS| | --- +---------+
|| | | | | -- | |
|+---------+ +----------+ | -- | GW |
| | -- +---------+ | | -- +---------+
| | -- | | -->
+----------+ -- +-------------------------+
--- +---------+
-- | |
-- | GW |
-- +---------+
-->
+---------+ +---------+
| | | |
| GW | | GW |
+---------+ +---------+
Figure 1: Gateway and LS Configuration Figure 1: Gateway and LS Configuration
The decision about which gateway to use depends on many factors, The decision about which gateway to use depends on many factors,
including their availability, remaining call capacity and call including their availability, remaining call capacity and call
success statistics to a particular PSTN destination. For the proxy to success statistics to a particular PSTN destination. For the proxy to
do this adequately, it needs to have access to this information in do this adequately, it needs to have access to this information in
real-time, as it changes. This means there must be some kind of real-time, as it changes. This means there must be some kind of
communications between the proxy and the gateways to convey this communications between the proxy and the gateways to convey this
information. information.
In this document, we specify a protocol for registration of routes In this document, we specify a protocol for registration of routes
(destinations) supported by the gateway to the TRIP Location Server, (destinations) supported by the gateway to the TRIP Location Server
known as Telephony Gateway REgistration Protocol (TGREP). TGREP [4], known as Telephony Gateway REgistration Protocol (TGREP). TGREP
Protocol can be considered an auxiliary protocol to TRIP. Routes Protocol can be considered an auxiliary protocol to TRIP. Routes
learnt through TGREP can be injected into and further processed learnt through TGREP can be injected into and further processed
and/or propogated by the TRIP Location Server. and/or propagated by the TRIP Location Server.
TGREP shares a lot of commonality with TRIP in various aspects. TGREP shares a lot of commonality with TRIP in various aspects.
Particularly, TGREP and TRIP have the same session establishment Particularly, TGREP and TRIP have the same session establishment
procedures, state machine, etc. TGREP also makes use of a similar procedures, state machine, etc. TGREP also makes use of a similar
UPDATE message to propogate the routes supported. It uses UPDATE message to propagate the routes supported. It uses
Notification, Keepalive and OPEN message in the same essence as TRIP. Notification, Keepalive and OPEN message in the same essence as TRIP.
TGREP defines few new attributes that are needed to specify certain TGREP defines few new attributes that are needed to specify certain
characteristics of gateways, like Available Capacity for a characteristics of gateways, like Available Capacity for a
destination. The document aims at specifying all the attributes destination. The document aims at specifying all the attributes
related to the TGREP session. This document also specifies some new related to the TGREP session. This document also specifies some new
address families which can be useful in advertising the information address families which can be useful in advertising the information
on the GWs. on the GWs.
As a general rule, because of lot of similarities between TRIP and As a general rule, because of lot of similarities between TRIP and
TGREP, frequent reference will be made to the terminologies and TGREP, frequent reference will be made to the terminologies and
formats defined in TRIP RFC[4]. It is suggested that the reader be formats defined in TRIP [4]. It is suggested that the reader be
familiar with the concepts of TRIP like attributes, flags, route familiar with the concepts of TRIP like attributes, flags, route
types, address families, etc. types, address families, etc.
3. Defining TGREP 3. TGREP: Overview of operation
TGREP is a route registration protocol for telephony destinations on TGREP is a route registration protocol for telephony destinations on
a gateway. These telephony destinations could be prefixes, trunk a gateway. These telephony destinations could be prefixes, trunk
groups or Carriers. The Speaker of TGREP resides on the GW and groups or Carriers. The Speaker of TGREP resides on the GW and
gathers all the information from the GW to relay to the other side. A gathers all the information from the GW to relay to the TRIP Location
TGREP Receiver is defined, which receives this information and after Server. A TGREP Receiver is defined, which receives this information
certain optional operations like consolidation and aggregation. and after certain optional operations like consolidation and
(defined in Sections 3.10.1 and 3.10.2) hands over the reachability aggregation. (defined in Sections 3.10.1 and 3.10.2) hands over the
information a to TRIP Location Server. reachability information a to TRIP Location Server.
The TGREP speaker establishes a session to the TGREP Receiver using The TGREP speaker establishes a session to the TGREP Receiver using
the procedures similar to session establishment in TRIP. The TGREP the procedures similar to session establishment in TRIP. The TGREP
Speaker is however, in "Send only" mode and the receiver is in the Speaker is however, in "Send only" mode and the receiver is in the
"Receive only" mode. After the session establishment the TGREP "Receive only" mode. After the session establishment the TGREP
speaker sends the reachibility informaton in the UPDATE messages. The speaker sends the reachibility information in the UPDATE messages.
UPDATE messages have the same format as in TRIP. However, certain The UPDATE messages have the same format as in TRIP. However, certain
TRIP attributes are not relevant in TGREP; a TGREP speaker MAY ignore TRIP attributes are not relevant in TGREP; a TGREP speaker MAY ignore
them if they are present in a TGREP message. In addition, TGREP them if they are present in a TGREP message. The following TRIP
defines the new attributes described in this document to be carried attributes do not apply to TGREP:
in a TGREP UPDATE message. 1. AdvertisementPath
2. RoutedPath
3. AtomicAggregate
4. LocalPreference
5. MultiExitDisc
6. ITADTopology
7. ConvertedRoute
In addition, TGREP defines the following new attributes in this
document that can be carried in a TGREP UPDATE message.
1. TotalCircuitCapacity
2. AvailableCircuits
3. CallSuccess
4. Prefix (E164)
5. Prefix (Decimal Routing Number)
6. Prefix (Hexadecimal Routing Number)
7. TrunkGroup
8. Carrier
In the rest of the document we specify attributes and address In the rest of the document we specify attributes and address
families used in TGREP. We also specify the operations of families used in TGREP. We also specify the operations of
consolidation and aggregation as they apply to the UPDATEs received consolidation and aggregation as they apply to the UPDATEs received
from the TGREP Gateway by the TGREP Receiver. from the TGREP Gateway by the TGREP Receiver.
4. TGREP Attributes
A TGREP UPDATE supports the following attributes: A TGREP UPDATE supports the following attributes:
1. WithdrawnRoutes (as defined in TRIP) 1. WithdrawnRoutes (as defined in TRIP)
2. ReachableRoutes (as defined in TRIP) 2. ReachableRoutes (as defined in TRIP)
3. NexthopServer (as defined in TRIP) 3. NexthopServer (as defined in TRIP)
4. TotalCircuitCapacity 4. TotalCircuitCapacity
5. AvailableCircuits 5. AvailableCircuits
6. CallSuccess 6. CallSuccess
7. Prefix 7. Prefix (E.164, Pentadecimal routing number, Decimal routing number)
8. TrunkGroup 8. TrunkGroup
9. Carrier 9. Carrier
10. Communities
3.1. TotalCircuitCapacity Attribute 4.1. TotalCircuitCapacity Attribute
Mandatory: False. Mandatory: False.
Required Flags: Not well-known. Required Flags: Not well-known.
Potential Flags: None. Potential Flags: None.
TRIP Type Code: 13 (To be assigned by IANA) TRIP Type Code: 13.
The TotalCircuitCapacity identifies the total number of PSTN circuits The TotalCircuitCapacity identifies the total number of PSTN circuits
that are available on a route to complete calls. It is used in that are available on a route to complete calls. It is used in
conjunction with the AvailableCircuits attribute in gateway selection conjunction with the AvailableCircuits attribute in gateway selection
by the LS. The total number of calls sent to the specified route on by the LS. The total number of calls sent to the specified route on
the gateway cannot exceed this total circuit capacity under steady the gateway cannot exceed this total circuit capacity under steady
state conditions. state conditions.
The TotalCircuitCapacity attribute is used to reflect the The TotalCircuitCapacity attribute is used to reflect the
administratively provisioned capacity as opposed to the availability administratively provisioned capacity as opposed to the availability
at a given point in time as provided by the AvailableCircuits at a given point in time as provided by the AvailableCircuits
attribute. Because of its relatively static nature, this attribute attribute. Because of its relatively static nature, this attribute
MAY be propogated beyond the LS that receives it. MAY be propagated beyond the LS that receives it.
TotalCircuitCapacity represents the total number of active calls at TotalCircuitCapacity represents the total number of active calls at
any instant. This is not expected to change frequently. This can any instant. This is not expected to change frequently. This can
change, for instance, when certain telephony trunks on the gateway change, for instance, when certain telephony trunks on the gateway
are taken out of service for maintenance purposes. are taken out of service for maintenance purposes.
3.1.1. TotalCircuitCapacity Syntax 4.1.1. TotalCircuitCapacity Syntax
The TotalCircuitCapacity attribute is a 4-octet unsigned numeric The TotalCircuitCapacity attribute is a 4-octet unsigned integer. It
value. It represents the total number of circuits available for represents the total number of circuits available for terminating
terminating calls through this advertised route. This attribute calls through this advertised route. This attribute represents a
represents a potentially achievable upper bound on the number of potentially achievable upper bound on the number of calls which can
calls which can be terminated on this route in total. be terminated on this route in total.
3.1.2. Route Origination and TotalCircuitCapacity 4.1.2. Route Origination and TotalCircuitCapacity
Routes MAY be originated containing the TotalCircuitCapacity Routes MAY be originated containing the TotalCircuitCapacity
attribute. attribute.
3.1.3. Route Selection and TotalCircuitCapacity 4.1.3. Route Selection and TotalCircuitCapacity
The TotalCircuitCapacity attribute MAY be used for route selection. The TotalCircuitCapacity attribute MAY be used for route selection.
Since one of its primary applications is load balancing, an LS will Since one of its primary applications is load balancing, an LS will
wish to choose a potentially different route (amongst a set of routes wish to choose a potentially different route (amongst a set of routes
for the same destination), on a call by call basis. This can be for the same destination), on a call by call basis. This can be
modeled as re-running the decision process on the arrival of each modeled as re-running the decision process on the arrival of each
call. The aggregation and dissemination rules for routes with this call. The aggregation and dissemination rules for routes with this
attribute ensure that re-running this selection process never results attribute ensure that re-running this selection process never results
in propagation of a new route to other peers. in propagation of a new route to other peers.
3.1.4. Aggregation and TotalCircuitCapacity 4.1.4. Aggregation and TotalCircuitCapacity
An LS MAY aggregate routes to the same prefix which contain a An LS MAY aggregate routes to the same prefix which contain a
TotalCircuitCapacity attribute. It SHOULD add the values of the TotalCircuitCapacity attribute. It SHOULD add the values of the
individual routes to determine the value for the aggregated route in individual routes to determine the value for the aggregated route in
the same ITAD. the same ITAD.
3.1.5. Route Dissemination and TotalCircuitCapacity 4.1.5. Route Dissemination and TotalCircuitCapacity
Since this attribute reflects the static capacity of the gateway's Since this attribute reflects the static capacity of the gateway's
circuit resources, it is not expected to change frequently. Hence the circuit resources, it is not expected to change frequently. Hence the
LS receiving this attribute MAY disseminate it to other peers, both LS receiving this attribute MAY disseminate it to other peers, both
internal and external to the ITAD. internal and external to the ITAD.
3.2. AvailableCircuits Attribute 4.2. AvailableCircuits Attribute
Mandatory: False. Mandatory: False.
Required Flags: Not well-known. Required Flags: Not well-known.
Potential Flags: None. Potential Flags: None.
TRIP Type Code: 14. (To be assigned by IANA) TRIP Type Code: 14.
The AvailableCircuits identifies the number of PSTN circuits that are The AvailableCircuits identifies the number of PSTN circuits that are
currently available on a route to complete calls. The number of currently available on a route to complete calls. The number of
additional calls sent to that gateway for that route cannot exceed additional calls sent to that gateway for that route cannot exceed
the circuit capacity. If it does, the signaling protocol will likely the circuit capacity. If it does, the signaling protocol will likely
generate errors, and calls will be rejected. generate errors, and calls will be rejected.
The AvailableCircuits attribute is used ONLY between a gateway and The AvailableCircuits attribute is used ONLY between a gateway and
its peer LS responsible for managing that gateway. If it is received its peer LS responsible for managing that gateway. If it is received
in a route, it is not propagated. in a route, it is not propagated.
3.2.1. AvailableCircuits Syntax 4.2.1. AvailableCircuits Syntax
The AvailableCircuits attribute is a 4-octet unsigned numeric value. The AvailableCircuits attribute is a 4-octet unsigned integer. It
It represents the number of circuits remaining for terminating calls represents the number of circuits remaining for terminating calls to
to this route. this route.
3.2.2. Route Origination and AvailableCircuits 4.2.2. Route Origination and AvailableCircuits
Routes MAY be originated containing the AvailableCircuits attribute. Routes MAY be originated containing the AvailableCircuits attribute.
Since this attribute is highly dynamic, changing with every call, Since this attribute is highly dynamic, changing with every call,
updates MAY be sent as it changes. However, it is RECOMMENDED that updates MAY be sent as it changes. However, it is RECOMMENDED that
measures be taken to help reduce the messaging load from route measures be taken to help reduce the messaging load from route
origination. It is further RECOMMENDED that sufficiently large origination. It is further RECOMMENDED that a sufficiently large
windows be used to provide a useful aggregated statistic. window of time be used to provide a useful aggregated statistic.
3.2.3. Route Selection and AvailableCircuits 4.2.3. Route Selection and AvailableCircuits
The AvailableCircuits attribute MAY be used for route selection. The AvailableCircuits attribute MAY be used for route selection.
Since one of its primary applications is load balancing, an LS will Since one of its primary applications is load balancing, an LS will
wish to choose a potentially different route (amongst a set of routes wish to choose a potentially different route (amongst a set of routes
for the same prefix) on a call by call basis. This can be modeled as for the same prefix) on a call by call basis. This can be modeled as
re-running the decision process on the arrival of each call. The re-running the decision process on the arrival of each call. The
aggregation and dissemination rules for routes with this attribute aggregation and dissemination rules for routes with this attribute
ensure that re-running this selection process never results in ensure that re-running this selection process never results in
propagation of a new route to other peers. propagation of a new route to other peers.
3.2.4. Aggregation and AvailableCircuits 4.2.4. Aggregation and AvailableCircuits
Not applicable Not applicable
3.2.5. Route Dissemination and AvailableCircuits 4.2.5. Route Dissemination and AvailableCircuits
Routes MUST NOT be disseminated with the AvailableCircuits attribute. Routes MUST NOT be disseminated with the AvailableCircuits attribute.
The attribute is meant to reflect capacity at the originating gateway The attribute is meant to reflect capacity at the originating gateway
only. Its highly dynamic nature makes it inappropriate to disseminate only. Its highly dynamic nature makes it inappropriate to disseminate
in most cases. in most cases.
3.3. CallSuccess Attribute 4.3. CallSuccess Attribute
Mandatory: False. Mandatory: False.
Required Flags: Not well-known. Required Flags: Not well-known.
Potential Flags: None. Potential Flags: None.
TRIP Type Code: 15. (To be assigned by IANA) TRIP Type Code: 15.
The CallSuccess attribute is an attribute used ONLY between a gateway The CallSuccess attribute is an attribute used ONLY between a gateway
and its peer LS responsible for managing that gateway. If it is and its peer LS responsible for managing that gateway. If it is
received in a route, it is not propagated. received in a route, it is not propagated.
The CallSuccess attribute provides information about the number of The CallSuccess attribute provides information about the number of
normally terminated calls out of a total number of attempted calls. normally terminated calls out of a total number of attempted calls.
CallSuccess is to be determined by the gateway based on the CallSuccess is to be determined by the gateway based on the
Disconnect cause code at call termination. For example, a call that Disconnect cause code at call termination. For example, a call that
reaches the Alerting stage but does not get connected due to the reaches the Alerting stage but does not get connected due to the
skipping to change at page 8, line 37 skipping to change at page 11, line 14
The CallSuccess attribute is used by the LS to keep track of failures The CallSuccess attribute is used by the LS to keep track of failures
in reaching certain telephony destinations through a gateway(s) and in reaching certain telephony destinations through a gateway(s) and
use that information in the gateway selection process to enhance the use that information in the gateway selection process to enhance the
probability of successful call termination. probability of successful call termination.
This information can be used by the LS to consider alternative This information can be used by the LS to consider alternative
gateways to terminate calls to those destinations with a better gateways to terminate calls to those destinations with a better
likelihood of success. likelihood of success.
3.3.1. CallSuccess Syntax 4.3.1. CallSuccess Syntax
The CallSuccess attribute is comprised of two component fields - each The CallSuccess attribute is comprised of two component fields - each
represented as an unsigned 4-octet numeric value. The first represented as an unsigned 4-octet unsigned integer. The first
component field represents the total number of calls terminated component field represents the total number of calls terminated
successfully for the advertised destination on a given address successfully for the advertised destination on a given address family
family. The second component field represents the total number of over a given window of time. The second component field represents
attempted calls for the advertised destination within some window of the total number of attempted calls for the advertised destination
time. within the same window of time.
3.3.2. Route Origination and CallSuccess 4.3.2. Route Origination and CallSuccess
Routes MAY be originated containing the CallSuccess attribute. This Routes MAY be originated containing the CallSuccess attribute. This
attribute is expected to get statistically significant with passage attribute is expected to get statistically significant with passage
of time as more calls are attempted. It is RECOMMENDED that of time as more calls are attempted. It is RECOMMENDED that
sufficiently large windows be used to provide a useful aggregated sufficiently large windows be used to provide a useful aggregated
statistic. statistic.
3.3.3. Route Selection and CallSuccess 4.3.3. Route Selection and CallSuccess
The CallSuccess attribute MAY be used for route selection. This The CallSuccess attribute MAY be used for route selection. This
attribute represents a measure of success of terminating calls to the attribute represents a measure of success of terminating calls to the
advertised destination(s). This information MAY be used to select advertised destination(s). This information MAY be used to select
from amongst a set of alternative routes to increase the probability from amongst a set of alternative routes to increase the probability
of successful call termination. of successful call termination.
3.3.4. Aggregation and CallSuccess 4.3.4. Aggregation and CallSuccess
Not applicable Not applicable
3.3.5. Route Dissemination and CallSuccess 4.3.5. Route Dissemination and CallSuccess
Routes MUST NOT be disseminated with the CallSuccess attribute. Its Routes MUST NOT be disseminated with the CallSuccess attribute. Its
potential to change dynamically does not make it suitable to potential to change dynamically does not make it suitable to
disseminate. disseminate.
3.4. Prefix Attributes 4.4. Prefix Attributes
Mandatory: False. Mandatory: False.
Required Flags: Not well-known. Required Flags: Not well-known.
Potential Flags: None. Potential Flags: None.
TRIP Type Codes: 16 for E164 prefix, 17 for pentadecimal prefix and TRIP Type Codes: 16 for E164 prefix, 17 for Pentadecimal routing number prefix
18 for decimal prefix (To be assigned by IANA) and 18 for Decimal routing number prefix.
The Prefix attribute is used to represent the list of prefixes that The Prefix attribute is used to represent the list of prefixes that
the respective route can complete calls to. This attribute is the respective route can complete calls to. This attribute is
intended to be used with the Carrier or Trunkgroup address family intended to be used with the Carrier or Trunkgroup address family
(discussed in Section 3.7). (discussed in Section 3.7).
Though it is possible that all prefix ranges may be reachable Though it is possible that all prefix ranges may be reachable
through a given Carrier, administrative issues could make certain through a given Carrier, administrative issues could make certain
ranges preferable to others. ranges preferable to others.
3.4.1. Prefix Attribute Syntax 4.4.1. Prefix Attribute Syntax
The Prefix attribute could be E.164, Decimal or PentaDecimal (refer The Prefix attribute could be E.164, Decimal or PentaDecimal (refer
to TRIP RFC [4]), each of them having it's own type code. The Prefix to TRIP [4]), each of them having it's own type code. The Prefix
attribute is encoded as a sequence of prefix values in the attribute attribute is encoded as a sequence of prefix values in the attribute
value field. The prefixes are listed sequentially with no padding as value field. The prefixes are listed sequentially with no padding as
shown in Figure 2. Each prefix includes a 2-octet length field that shown in Figure 2. Each prefix includes a 2-octet length field that
represents the length of the address field in octets. The order of represents the length of the address field in octets. The order of
prefixes in the attribute is not significant. prefixes in the attribute is not significant.
The presence of Prefix Attribute with the length field of the The presence of Prefix Attribute with the length field of the
attribute as 0 signifies that the TGREP GW can terminate ALL prefixes attribute as 0 signifies that the TGREP GW can terminate ALL prefixes
for the given Reachable route(s). of that prefix type (E.164, Decimal or Pentadecimal) for the given
Reachable route(s). This is not equivalent to excluding the Prefix
attribute in the TGREP update.
1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 . . . 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 . . . 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4
+-------------------------------+-----------+----------------------------------+----------- +-------------------------------+-----------+----------------------------------+-----------
| Length | Prefix1...| Length | Prefix2... | Length | Prefix1...| Length | Prefix2...
+-------------------------------+-----------+----------------------------------+----------- +-------------------------------+-----------+----------------------------------+-----------
Figure 2: Prefix Format Figure 2: Prefix Format
3.4.2. Route Origination and Prefix 4.4.2. Route Origination and Prefix
Routes MAY be originated containing the Prefix attribute. Routes MAY be originated containing the Prefix attribute.
3.4.3. Route Selection and Prefix 4.4.3. Route Selection and Prefix
The Prefix attribute MAY be used for route selection. The Prefix attribute MAY be used for route selection.
3.4.4. Aggregation and Prefix 4.4.4. Aggregation and Prefix
Routes with differing Prefix attribute MUST NOT be aggregated. Routes with differing Prefix attribute MUST NOT be aggregated.
Routes with the same value in the Prefix attribute MAY be aggregated Routes with the same value in the Prefix attribute MAY be aggregated
and the same Prefix attribute attached to the aggregated object. and the same Prefix attribute attached to the aggregated object.
3.4.5. Route Dissemination and Prefix 4.4.5. Route Dissemination and Prefix
The LS receiving this attribute should disseminate to other peers, The LS receiving this attribute should disseminate to other peers,
both internal and external to the ITAD. both internal and external to the ITAD.
3.5. TrunkGroup Attribute 4.5. TrunkGroup Attribute
Mandatory: False. Mandatory: False.
Required Flags: Not well-known. Required Flags: Not well-known.
Potential Flags: None. Potential Flags: None.
TRIP Type Code: 20 (To be assigned by IANA) TRIP Type Code: 20.
The TrunkGroup attribute is used to represent the list of trunkgroups The TrunkGroup attribute is used to represent the list of trunkgroups
on the gateway used to complete calls. It enables providers to route on the gateway used to complete calls. It enables providers to route
calls to destinations through preferred trunks. This attribute is calls to destinations through preferred trunks. This attribute is
relatively static. relatively static.
3.5.1. TrunkGroup Syntax 4.5.1. TrunkGroup Syntax
The TrunkGroup attribute is a variable length attribute that is The TrunkGroup attribute is a variable length attribute that is
composed of a sequence of trunkgroup length-value fields. It composed of a sequence of trunkgroup length-value fields. It
indicates that the gateway can complete the call through any indicates that the gateway can complete the call through any
trunkgroup (represented by the trunkgroup label) in the sequence. trunkgroup (represented by the trunkgroup label) in the sequence.
Each trunkgroup is a length-value field (shown in Figure 3 below). Each trunkgroup is a length-value field (shown in Figure 3 below).
The length field is a 1-octet unsigned numeric value. The value field The length field is a 1-octet unsigned numeric value. The value field
is a variable length alphanumeric field and is also called the is a variable length alphanumeric field and is also called the
trunkgroup label field. The length field represents the size of the trunkgroup label field. The length field represents the size of the
skipping to change at page 11, line 42 skipping to change at page 14, line 17
attribute as 0 signifies that the TGREP GW can terminate ALL attribute as 0 signifies that the TGREP GW can terminate ALL
trunkgroup for the given Reachable route(s). trunkgroup for the given Reachable route(s).
0 1 0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 ... 7 8 9 0 1 2 3 4 5 ... 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 ... 7 8 9 0 1 2 3 4 5 ...
+---------------+--------------------+---------------+--------------------- +---------------+--------------------+---------------+---------------------
| Length | TrunkGroup Label1..| Length | TrunkGroup Label2.. | Length | TrunkGroup Label1..| Length | TrunkGroup Label2..
+---------------+--------------------+---------------+--------------------- +---------------+--------------------+---------------+---------------------
Figure 3: TrunkGroup Syntax Figure 3: TrunkGroup Syntax
3.5.2. Route Origination and TrunkGroup 4.5.2. Route Origination and TrunkGroup
Routes MAY be originated containing the TrunkGroupattribute. Routes MAY be originated containing the TrunkGroupattribute.
3.5.3. Route Selection and TrunkGroup 4.5.3. Route Selection and TrunkGroup
The TrunkGroup attribute MAY be used for route selection. Certain The TrunkGroup attribute MAY be used for route selection. Certain
trunkgroups MAY be preferred over others based on provider policy. trunkgroups MAY be preferred over others based on provider policy.
3.5.4. Aggregation and TrunkGroup 4.5.4. Aggregation and TrunkGroup
Routes with differing TrunkGroup attribute MUST NOT be aggregated. Routes with differing TrunkGroup attribute MUST NOT be aggregated.
Routes with the same value in the TrunkGroup attribute MAY be Routes with the same value in the TrunkGroup attribute MAY be
aggregated and the same TrunkGroup attribute attached to the aggregated and the same TrunkGroup attribute attached to the
aggregated object. aggregated object.
3.5.5. Route Dissemination and TrunkGroup 4.5.5. Route Dissemination and TrunkGroup
This attribute is not expected to change frequently. Hence, the LS This attribute is not expected to change frequently. Hence, the LS
receiving this attribute MAY disseminate it to other peers, internal receiving this attribute MAY disseminate it to other peers, internal
to ITAD. Routes SHOULD not be disseminated external to the ITAD, with to ITAD. Routes SHOULD not be disseminated external to the ITAD, with
TrunkGroup attribute. TrunkGroup attribute.
3.6. Carrier Attribute 4.6. Carrier Attribute
Mandatory: False. Mandatory: False.
Required Flags: Not well-known. Required Flags: Not well-known.
Potential Flags: None. Potential Flags: None.
TRIP Type Code: 19 (To be assigned by IANA) TRIP Type Code: 19.
The Carrier attribute is used to represent the list of carriers that The Carrier attribute is used to represent the list of carriers that
the gateway uses to complete calls. It enables providers to route the gateway uses to complete calls. It enables providers to route
calls to destinations through preferred carriers. This attribute is calls to destinations through preferred carriers. This attribute is
relatively static. relatively static.
3.6.1. Carrier Syntax 4.6.1. Carrier Syntax
The Carrier attribute is a variable length attribute that is composed The Carrier attribute is a variable length attribute that is composed
of a sequence of carrier values. It indicates that the route can of a sequence of carrier values. It indicates that the route can
complete the call to any of the carriers represented in the sequence complete the call to any of the carriers represented in the sequence
of carrier values. of carrier values.
A Carrier value is an 8-octet ASCII-encoded string obtained by A Carrier value is an 8-octet ASCII-encoded string obtained by
concatenation of a CarrierIdCode and a RegionCode ( defined below ). concatenation of a CarrierIdCode and a RegionCode ( defined below ).
When the length of the Carrier value is less than 8 octets, it is When the length of the Carrier value is less than 8 octets, it is
padded with NULL bytes padded with NULL bytes.
The CarrierIdCode is the code assigned to a carrier by a regulatory The CarrierIdCode is the code assigned to a carrier by a regulatory
body operating in that region. The RegionCode represents the region body operating in that region. The RegionCode represents the region
where the CarrierIdCode is assigned. The RegionCode is a qualifier where the CarrierIdCode is assigned. The RegionCode is a qualifier
that makes the Carrier value globally unique. Regions are currently that makes the Carrier value globally unique. Regions are currently
defined to map to countries. The RegionCode should use E.164 country defined to map to countries. The RegionCode should use E.164 country
code used in dialing international telephony destinations. However, code used in dialing international telephony destinations. However,
regions can evolve in the future to encompass a larger area, beyond a regions can evolve in the future to encompass a larger area, beyond a
country. For example, if a regulatory body in the European Union that country. For example, if a regulatory body in the European Union that
assigns CarrierIds to carriers in the whole of Europe, a assigns CarrierIds to carriers in the whole of Europe, a
skipping to change at page 13, line 38 skipping to change at page 16, line 17
for the given Reachable route(s). for the given Reachable route(s).
0 1 2 7 0 0 1 2 7 0
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 .....0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 .. 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 .....0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 ..
+-------------------------------------------------------------+--------------- +-------------------------------------------------------------+---------------
| Carrier1 | Carrier2 .. | Carrier1 | Carrier2 ..
+-------------------------------------------------------------+--------------- +-------------------------------------------------------------+---------------
Figure 4: Carrier Syntax Figure 4: Carrier Syntax
3.6.2. Route Origination and Carrier 4.6.2. Route Origination and Carrier
Routes MAY be originated containing the Carrier attribute. Routes MAY be originated containing the Carrier attribute.
3.6.3. Route Selection and Carrier 4.6.3. Route Selection and Carrier
The Carrier attribute MAY be used for route selection. Certain The Carrier attribute MAY be used for route selection. Certain
carriers MAY be preferred over others based on provider policy. carriers MAY be preferred over others based on provider policy.
3.6.4. Aggregation and Carrier 4.6.4. Aggregation and Carrier
Routes with differing Carrier attribute MUST NOT be aggregated. Routes with differing Carrier attribute MUST NOT be aggregated.
Routes with the same value in the Carrier attribute MAY be aggregated Routes with the same value in the Carrier attribute MAY be aggregated
and the same Carrier attribute attached to the aggregated object. and the same Carrier attribute attached to the aggregated object.
3.6.5. Route Dissemination and Carrier 4.6.5. Route Dissemination and Carrier
This attribute is not expected to change frequently. Hence, the LS This attribute is not expected to change frequently. Hence, the LS
receiving this attribute MAY disseminate it to other peers, both receiving this attribute MAY disseminate it to other peers, both
internal and external to the ITAD. internal and external to the ITAD.
3.7. TrunkGroup and Carrier Address Families 4.7. TrunkGroup and Carrier Address Families
As described in TRIP [4], the address family field gives the type of
address for the route. Two new address families and their codes are
defined in this Section:
Code Address Family
4 TrunkGroup
5 Carrier
When a set of GWs are to managed at the granularity of carriers or When a set of GWs are to managed at the granularity of carriers or
trunkgroups then it may be more appropriate for a GW to advertise trunkgroups then it may be more appropriate for a GW to advertise
routes using the Carrier address family or trunkgroup address family routes using the Carrier address family or trunkgroup address family
respectively. Also, in a TGREP association between the gateway and respectively. Also, in a TGREP association between the gateway and
the LS responsible for managing that gateway, there are some the LS responsible for managing that gateway, there are some
attributes that more naturally fit in as advertised properties of attributes that more naturally fit in as advertised properties of
trunkgroups or carriers rather than that of advertised prefixes; for trunkgroups or carriers rather than that of advertised prefixes; for
example, the AvailableCircuit information on a particular trunkgroup example, the AvailableCircuit information on a particular trunkgroup
or a particular carrier. To express this relationship, the existing or a particular carrier. To express this relationship, the existing
TRIP address families are inadequate. We need separate address TRIP address families are inadequate. We need separate address
skipping to change at page 15, line 5 skipping to change at page 17, line 31
- it facilitates more accurate reporting of attributes of a dynamic - it facilitates more accurate reporting of attributes of a dynamic
nature like AvailableCircuits by providing the ability to manage nature like AvailableCircuits by providing the ability to manage
resources at the granularity of a trunkgroup or a carrier. resources at the granularity of a trunkgroup or a carrier.
- Gateways can get really large with the ability to provision - Gateways can get really large with the ability to provision
hundreds or a few thousand circuits and this can increase the hundreds or a few thousand circuits and this can increase the
potential for traffic that reports dynamic resource information potential for traffic that reports dynamic resource information
between the gateway and the LS. The model introduced can between the gateway and the LS. The model introduced can
potentially alleviate this UPDATE traffic hence increasing potentially alleviate this UPDATE traffic hence increasing
efficiency and providing a scalable gateway registration model. efficiency and providing a scalable gateway registration model.
3.7.1. Address Family Syntax 4.7.1. Address Family Syntax
Consider the generic TRIP route format from TRIP[4] shown below. Consider the generic TRIP route format from TRIP[4] shown below.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+--------------+----------------+ +---------------+---------------+--------------+----------------+
| Address Family | Application Protocol | | Address Family | Application Protocol |
+---------------+---------------+--------------+----------------+---- +---------------+---------------+--------------+----------------+----
| Length | Address (variable) .... | Length | Address (variable) ....
+---------------+---------------+--------------+----------------+---- +---------------+---------------+--------------+----------------+----
Figure 5: Generic TRIP Route Format Figure 5: Generic TRIP Route Format
The Address Family field will be used to represent the type of the The Address Family field will be used to represent the type of the
address associated for this family, which is based on the TrunkGroup address associated for this family, which is based on the TrunkGroup
or Carrier. The codes for the new address families will be allocated or Carrier. The codes for the new address families will be allocated
by IANA. by IANA.
The code for the trunk group address family is XX [[NOTE TO RFC-ED:
Please replace XX with the IANA assigned value for the trunk group
address family]] and the code for the carrier address family is XXX
[[NOTE TO RFC-ED: Please replace XX with the IANA assigned value for
the carrier address family]].
The Application Protocol field is same as the one for the Decimal, The Application Protocol field is same as the one for the Decimal,
PentaDecimal and E.164 address families defined in TRIP[4]. The PentaDecimal and E.164 address families defined in TRIP[4]. The
Length field represents the total size of the Address field in bytes. Length field represents the total size of the Address field in bytes.
The value in the Address field represents either the TrunkGroup or The value in the Address field represents either the TrunkGroup or
the Carrier address families and the syntax is as follows: the Carrier address families and the syntax is as follows:
For the TrunkGroup Address Family, the Address field is a variable For the TrunkGroup Address Family, the Address field is a variable
length alphanumeric field (trunkgroup label), where length is length alphanumeric field (trunkgroup label), where length is
determined by the length field of the route. The maximum value of the determined by the length field of the route. The maximum value of the
length field for this Address Family is 128 bytes. length field for this Address Family is 128 bytes.
For the Carrier Address Family, the length field represents the For the Carrier Address Family, the length field represents the
length of the Address field in bytes. The Address field is a fixed length of the Address field in bytes. The Address field is a fixed
length field representing Carrier value. A Carrier value is an 8- length field representing Carrier value. The format of the Carrier
octet ASCII-encoded string obtained by concatenation of a value is as specified in the earlier section on "Carrier attribute"
CarrierIdCode and a RegionCode ( defined below ). When the length of
the Carrier value is less than 8 octets, it is padded with NULL bytes
The CarrierIdCode is the code assigned to a carrier by a regulatory The CarrierIdCode is the code assigned to a carrier by a regulatory
body operating in that region. The RegionCode represents the region body operating in that region. The RegionCode represents the region
where the CarrierIdCode is assigned. The RegionCode is a qualifier where the CarrierIdCode is assigned. The RegionCode is a qualifier
that makes the Carrier value globally unique. Regions are currently that makes the Carrier value globally unique. Regions are currently
defined to map to countries. The RegionCode should use E.164 country defined to map to countries. The RegionCode should use E.164 country
code used in dialing international telephony destinations. However, code used in dialing international telephony destinations. However,
regions can evolve in the future to encompass a larger area, beyond a regions can evolve in the future to encompass a larger area, beyond a
country. For example, if a regulatory body in the European Union that country. For example, if a regulatory body in the European Union that
assigns CarrierIds to carriers in the whole of Europe, a assigns CarrierIds to carriers in the whole of Europe, a
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It is recommended that the above three attributes be used by the It is recommended that the above three attributes be used by the
gateway with the TrunkGroup or Carrier address families, if possible. gateway with the TrunkGroup or Carrier address families, if possible.
This will potentially offer a more efficient resource reporting This will potentially offer a more efficient resource reporting
framework, and a scalable model for gateway provisioning. framework, and a scalable model for gateway provisioning.
However, when the gateway is not using TrunkGroup or Carrier address However, when the gateway is not using TrunkGroup or Carrier address
family, it MAY use the above attributes with the Decimal, family, it MAY use the above attributes with the Decimal,
PentaDecimal and E.164 address families. PentaDecimal and E.164 address families.
The Prefix, Carrier and TrunkGroup attributes MUST NOT be used with The prefix attribute cannot be used when the address family is E164
their respective address families. numbers, Pentadecimal routing numbers or Decimal routing numbers.
3.8. Gateway Operation The Carrier attribute cannot be used if the address family type is
Carrier
The TrunkGroup attribute cannot be used if the address family type is
TrunkGroup
4.8. Gateway Operation
A gateway uses TGREP to advertise its reachability to its domain's A gateway uses TGREP to advertise its reachability to its domain's
Location Server(s) (LS, which are closely coupled with proxies). The Location Server(s) (LS, which are closely coupled with proxies). The
gateway operates in TGREP Send Only mode since it is only interested gateway operates in TGREP Send Only mode since it is only interested
in advertising its reachability, but is not interested in learning in advertising its reachability, but is not interested in learning
about the reachability of other gateways and other domains. Also, the about the reachability of other gateways and other domains. Also, the
gateway will not create its own call routing database. In this gateway will not create its own call routing database. In this
section we describe the operation of TGREP on a gateway. section we describe the operation of TGREP on a gateway.
3.8.1. Session Establishment 4.8.1. Session Establishment
When opening a peering session with a TGREP Receiver, a TGREP gateway When opening a peering session with a TGREP Receiver, a TGREP gateway
follows exactly the same procedures as any other TRIP speaker. The follows exactly the same procedures as any other TRIP speaker. The
TGREP gateway sends an OPEN message which includes a Send Receive TGREP gateway sends an OPEN message which includes a Send Receive
Capability in the Optional Parameters. The Send Receive Capability is Capability in the Optional Parameters. The Send Receive Capability is
set by the gateway to Send Only. The OPEN message also contains the set by the gateway to Send Only. The OPEN message also contains the
address families supported by the gateway. The remainder of the peer address families supported by the gateway. The remainder of the peer
session establishment is identical to TRIP. session establishment is identical to TRIP.
3.8.2. UPDATE Messages 4.8.2. UPDATE Messages
Once the peer session has been established, the gateway sends UPDATE Once the peer session has been established, the gateway sends UPDATE
messages to the TRIP LS with the gateway's entire reachability. The messages to the TRIP LS with the gateway's entire reachability. The
Gateway also sends any attributes associated with the routes. Gateway also sends any attributes associated with the routes.
If the gateway's reachability changes at any point in time, the If the gateway's reachability changes at any point in time, the
gateway MUST generate UPDATE message(s) with the change. The gateway MUST generate UPDATE message(s) with the change. The
frequency of successive UPDATE messages MUST follow the same rules frequency of successive UPDATE messages MUST follow the same rules
specified for TRIP[4]. The TGREP gateway MUST support all mandatory specified for TRIP[4]. The TGREP gateway MUST support all mandatory
TRIP attributes. TRIP attributes.
If the gateway receives an UPDATE message from the TRIP LS, it MUST If the gateway receives an UPDATE message from the TRIP LS, it MUST
silently discard it as specified for TRIP[4]. No further action silently discard it as specified for TRIP[4]. No further action
should be taken. should be taken.
3.8.3. KEEPALIVE Messages 4.8.3. KEEPALIVE Messages
KEEPALIVE messages are periodically exchanged over the peering KEEPALIVE messages are periodically exchanged over the peering
session between the TGREP gateway and the TRIP LS as specified in session between the TGREP gateway and the TRIP LS as specified in
Section 4.4 of TRIP RFC[4]. Section 4.4 of TRIP [4].
3.8.4. Error Handling and NOTIFICATION Messages 4.8.4. Error Handling and NOTIFICATION Messages
The same procedures used with TRIP, are used with TGREP for error The same procedures used with TRIP, are used with TGREP for error
handling and generating NOTIFICATION messages. The only difference is handling and generating NOTIFICATION messages. The only difference is
that a TGREP gateway will never generate a NOTIFICATION message in that a TGREP gateway will never generate a NOTIFICATION message in
response to an UPDATE message, irrespective of the contents of the response to an UPDATE message, irrespective of the contents of the
UPDATE message. Any UPDATE message is silently discarded. UPDATE message. Any UPDATE message is silently discarded.
3.8.5. TGREP Finite State Machine 4.8.5. TGREP Finite State Machine
When the TGREP finite state machine is in the Established state and When the TGREP finite state machine is in the Established state and
an UPDATE message is received, the UPDATE message is silently an UPDATE message is received, the UPDATE message is silently
discarded and the TGREP gateway remains in the Established state. discarded and the TGREP gateway remains in the Established state.
Other than that the TRIP finite state machine and the TGREP finite Other than that the TRIP finite state machine and the TGREP finite
state machine are identical. state machine are identical.
3.8.6. Call Routing Databases 4.8.6. Call Routing Databases
A TGREP gateway may maintain simultaneous sessions with more than one A TGREP gateway may maintain simultaneous sessions with more than one
TRIP LSs. A TGREP gateway maintains one call routing database per TRIP LSs. A TGREP gateway maintains one call routing database per
peer TRIP LS. These databases are equivalent to TRIP's Adj-TRIBs-Out, peer TRIP LS. These databases are equivalent to TRIP's Adj-TRIBs-Out,
and hence we will call them Adj-TRIB-GWs-Out. An Adj-TRIB-GW-Out and hence we will call them Adj-TRIB-GWs-Out. An Adj-TRIB-GW-Out
contains the gateway's reachability information advertised to its contains the gateway's reachability information advertised to its
peer TRIP LS. How an Adj-TRIB-GW-Out database gets populated is peer TRIP LS. How an Adj-TRIB-GW-Out database gets populated is
outside the scope of this draft (possibly by manual configuration). outside the scope of this draft (possibly by manual configuration).
The TGREP gateway does not have databases equivalent to TRIP's Adj- The TGREP gateway does not have databases equivalent to TRIP's Adj-
TRIBs-In and Loc-TRIB, because the TGREP gateway does not learn TRIBs-In and Loc-TRIB, because the TGREP gateway does not learn
routes from its peer TRIP LSs, and hence it does not run call route routes from its peer TRIP LSs, and hence it does not run call route
selection. selection.
3.8.7. Multiple Address Families 4.8.7. Multiple Address Families
As mentioned above, TGREP supports various address families in order As mentioned above, TGREP supports various address families in order
to convey the reachibilty of telephony destinations. A TGREP session to convey the reachabilty of telephony destinations. A TGREP session
MUST NOT send UPDATEs of more than one of the following catagories MUST NOT send UPDATEs of more than one of the following categories
(a) Prefix Address families (E164, Pentadecimal and decimal) (b) (a) Prefix Address families (E164, Pentadecimal and decimal) (b)
Trunkgroup address family (c) Carrier Address family for a given Trunkgroup address family (c) Carrier Address family for a given
established session. TGREP should specify it's choice address family established session. TGREP should specify it's choice address family
through the route-type capability in the OPEN message. And route-type through the route-type capability in the OPEN message. And route-type
specification in the OPEN message violating the above rule should be specification in the OPEN message violating the above rule should be
rejected with a NOTIFICATION message. rejected with a NOTIFICATION message.
3.8.8. Route Selection and Aggregation 4.8.8. Route Selection and Aggregation
TRIP's route selection and aggregation operations MUST NOT be TRIP's route selection and aggregation operations MUST NOT be
implemented by TGREP gateways. implemented by TGREP gateways.
3.9. LS/Proxy Behavior 4.9. LS/Proxy Behavior
As mentioned earlier, TGREP can be considered as a protocol As mentioned earlier, TGREP can be considered as a protocol
complimentary to TRIP in providing reachability information that can complimentary to TRIP in providing reachability information that can
then be further fed into the Location Server. The architecture of an then be further fed into the Location Server. The architecture of an
LS/Proxy system is as follows: There exists a TRIP LS application LS/Proxy system is as follows: There exists a TRIP LS application
that functions as a speaker in the I-TRIP/E-TRIP network as that functions as a speaker in the I-TRIP/E-TRIP network as
documented in the TRIP RFC [4]. Then, there is a signaling server documented in TRIP [4]. This component is termed as "LS-Egress" for
fronting a set of gateways and receives routing information on one or the purposes of this discussion. Then, there is a signaling server
more TGREP sessions. This routing information from the gateways is fronting a set of gateways. In conjunction with this signaling
received and processed by a TGREP receiver application. Subsequently, server, is also a second TRIP LS component operating in receive mode,
this routing information is presented as candidate routes (possibly that peers with one more gateways, each of them using TGREP to
as local routes) to the TRIP LS. The interface between these two advertise routing information. This TRIP LS component on the
applications is entirely a local matter. However, before importing receiving end of one or more TGREP sessions is termed as the "LS-
these routes into the TRIP LS, certain operations may optionally be Ingress" or "TGREP Receiver" for the purposes of this discussion. The
performed on these routes. The nature of these operations and the LS-Ingress receiving the TRIP messages takes the resulting routing
information from each gateway, and "exports" it to another process we
are defining that performs consolidation and aggregation, in that
order. These operations would take as input the collective set of
routes from all the gateways. Subsequently, the resulting TRIB is
passed as input into the LS-Egress process as shown below, that can
then disseminate these via TRIP. The interface between the LS-Ingress
peering with the GW(s) and the TRIP LS (LS-Egress) is entirely a
local matter.
The nature of the Consolidation and Aggregation operations and the
accompanying motivation are described in the subsections below. The accompanying motivation are described in the subsections below. The
order in which the operations are listed represents an implicit order in which the operations are listed represents an implicit
logical sequence in which they are applied. The architecture for an logical sequence in which they are applied. The architecture for an
LS/Proxy entity is shown in Figure 7 below. LS/Proxy entity is shown in Figure 7 below.
+-------------------------------------------------------+ +-------------------------------------------------------+
| +-------------------------------+ | | +-------------------------------+ |
| | +-+ +-+ | | | | +-+ +-+ | |
| | |A| |C| | | +-----+ | | |A| |C| | | +-----+
| | |g| |o| | | TGREP | | | | |g| |o| | | TGREP | |
| +-------------+ | |g| |n| +-------------+ | | -- | GW | | +-------------+ | |g| |n| +-------------+ | | -- | GW |
| | | | |r| |s| | | | | -- +-----+ | | | | |r| |s| | | | | -- +-----+
| | TRIP | | |e| |o| | | | +-- | | TRIP | | |e| |o| | | | +--
| | LS <----------|g<--|l<--- TGREP |-++-| +-----+ | | LS <----------|g<--|l<--- TGREP |-++-| +-----+
| | | | |a| |i| | Session | | | | | | | | | |a| |i| | Session | | | | |
| | (I-TRIP/ | | |t| |d| | Mangement |-++-+-------| GW | | | (I-TRIP/ | | |t| |d| | Management |-++-+-------| GW |
| | E-TRIP) | | |i| |a| | | | | +-----+ | | E-TRIP) | | |i| |a| | | | | +-----+
| | | | |o| |t| | |-+ -+- | | (LS-Egress) | | |o| |t| | |-+ -+-
| +-----------/-+ | |n| |i| +-------------+ | | --- +-----+ | +-----------/-+ | |n| |i| +-------------+ | | --- +-----+
| / | | | |o| | | -- | | | / | | | |o| | | -- | |
| / | | | |n| | | | GW | | / | | | |n| (LS-Ingress) | | | GW |
| / | +-+ +-+ | | +-----+ | / | +-+ +-+ | | +-----+
| / | TGREP Receiver | | | / | TGREP Receiver | |
| / +-------------------------------+ | | / +-------------------------------+ |
| / | | / |
| / | | / |
+-------/-----------------------------------------------+ +-------/-----------------------------------------------+
/ LS/Proxy / LS/Proxy
/ /
/ /
/ /
skipping to change at page 21, line 13 skipping to change at page 24, line 13
+------------------------------------------------------+ +------------------------------------------------------+
| +-------------------------------+ | | +-------------------------------+ |
| | +-+ +-+ | | | | +-+ +-+ | |
| | |A| |C| | | +-----+ | | |A| |C| | | +-----+
| | |g| |o| | | TGREP | | | | |g| |o| | | TGREP | |
| +-------------+ | |g| |n| +-------------+ | | -- | GW | | +-------------+ | |g| |n| +-------------+ | | -- | GW |
| | | | |r| |s| | | | | -- +-----+ | | | | |r| |s| | | | | -- +-----+
| | TRIP | | |e| |o| | | | +-- | | TRIP | | |e| |o| | | | +--
| | LS <----------|g<--|l<--- TGREP |-++-| +-----+ | | LS <----------|g<--|l<--- TGREP |-++-| +-----+
| | | | |a| |i| | Session | | | | | | | | | |a| |i| | Session | | | | |
| | (I-TRIP/ | | |t| |d| | Mangement |-++-+-------| GW | | | (I-TRIP/ | | |t| |d| | Management |-++-+-------| GW |
| | E-TRIP) | | |i| |a| | | | | +-----+ | | E-TRIP) | | |i| |a| | | | | +-----+
| | | | |o| |t| | |-+ -+- | | (LS-Egress) | | |o| |t| | |-+ -+-
| +-------------+ | |n| |i| +-------------+ | | --- +-----+ | +-------------+ | |n| |i| +-------------+ | | --- +-----+
| | | | |o| | | -- | | | | | | |o| | | -- | |
| | | | |n| | | | GW | | | | | |n| | | | GW |
| | +-+ +-+ | | +-----+ | | +-+ +-+ (LS-Ingress) | | +-----+
| | TGREP Receiver | | | | TGREP Receiver | |
| +-------------------------------+ | | +-------------------------------+ |
| | | |
| | | |
+-------------------------------------------------------+ +-------------------------------------------------------+
LS/Proxy LS/Proxy
Figure 7: LS Architecture for TRIP-GW Figure 7: LS Architecture for TRIP-GW
3.9.1. Route consolidation 4.9.1. Route consolidation
The TGREP receiver may receive routing information from one or more The TGREP receiver (LS-Ingress) may receive routing information from
gateways. It is possible that multiple routes are available for the one or more gateways. It is possible that multiple routes are
same destination. These different alternative routes may be received available for the same destination. These different alternative
from the same gateway, or from multiple gateways. It is RECOMMENDED routes may be received from the same gateway, or from multiple
that the set of gateway routes for each destination be consolidated, gateways. It is RECOMMENDED that the set of gateway routes for each
before presenting a candidate route, to the TRIP LS. The motivation destination be consolidated, before presenting a candidate route, to
for this operation should be to define a route that can maximally the LS-Egress entity. The motivation for this operation should be to
represent the collective routing capabilities of the set of gateways, define a route that can maximally represent the collective routing
managed by this TGREP receiver. Let us take an example scenario in capabilities of the set of gateways, managed by this TGREP receiver.
order to bring out the motivation for this operation. Let us say, Let us take an example scenario in order to bring out the motivation
the TGREP receiver maintains peering sessions with gateways A, and B. for this operation. Let us say, the TGREP receiver maintains peering
sessions with gateways A, and B.
o Gateway A advertises a route for destination "SIP 408" on the E.164 - Gateway A advertises a route for destination "SIP 408" on the
address E.164 address family with the Carrier attribute value C1.
family with the Carrier attribute value C1.
o Gateway B advertises a route for destination "SIP 408" on the E.164 - Gateway B advertises a route for destination "SIP 408" on the
address E.164 address family with Carrier attribute value C2.
family with Carrier attribute value C2.
The TGREP receiver that receives these routes can consolidate these The TGREP receiver that receives these routes can consolidate
constituent routes into a single route for destination "SIP 408" with these constituent routes into a single route for destination "SIP
its Carrier attribute being a union of the the Carrier attribute 408" with its Carrier attribute being a union of the the Carrier
values of the individual routes, namely, "C1 C2". This operation is attribute values of the individual routes, namely, "C1 C2". This
refered to as Consolidation. In the above example, it is possible operation is referred to as Consolidation. In the above example,
that a route to the destination "SIP 408" through one or more it is possible that a route to the destination "SIP 408" through
carriers may have been lost if the individual routes were not one or more carriers may have been lost if the individual routes
consolidated. were not consolidated.
Another example is to consolidate the Prefix attribute from multiple Another example is to consolidate the Prefix attribute from
Carrier or Trunkgroup updates received from different gateways for multiple Carrier or Trunkgroup updates received from different
the same destination. Let us say, there are Carrier AF updates from gateways for the same destination. Let us say, there are Carrier
two gateways for Carrier destination X, and the prefix attribute AF updates from two gateways for Carrier destination X, and the
values are {408, 650} from one update and {919, 973} from the other. prefix attribute values are {408, 650} from one update and {919,
The prefix values from these two updates can be consolidated into a 973} from the other. The prefix values from these two updates can
single Carrier AF route advertisement with prefix value {408, 650, be consolidated into a single Carrier AF route advertisement with
919, 973}. prefix value {408, 650, 919, 973}.
In general, there is a potential for loss of gateway routing In general, there is a potential for loss of gateway routing
information, when TGREP routes from a set of gateways are not information, when TGREP routes from a set of gateways are not
consolidated, when a candidate route is presented to the TRIP LS. consolidated, when a candidate route is presented to the TRIP LS.
The specifics of applying the consolidation operation to different The specifics of applying the consolidation operation to
attributes and routes from different address families, is left to the different attributes and routes from different address families,
individual TGREP receiver implementations. is left to the individual TGREP receiver implementations.
3.9.2. Aggregation 4.9.2. Aggregation
The set of gateway routes, that are in a consolidated form or The set of gateway routes, that are in a consolidated form or
otherwise, may be aggregated before importing it to the LS instance otherwise, may be aggregated before importing it to the LS instance
that is responsible for I-TRIP/E-TRIP processing. This operation that is responsible for I-TRIP/E-TRIP processing (LS-Egress). This
follows the standard aggregation procedures described in the TRIP RFC operation follows the standard aggregation procedures described in
[4], while adhering to the aggregation rules for each route the TRIP [4], while adhering to the aggregation rules for each route
attribute. attribute.
3.9.3. Consolidation v/s Aggregation 4.9.3. Consolidation v/s Aggregation
To highlight the difference between the two operations discussed To highlight the difference between the two operations discussed
above, "Consolidation" combines multiple routes for the same route above, "Consolidation" combines multiple routes for the same route
destination, whereas "Aggregation" combines routes for different destination, whereas "Aggregation" combines routes for different
route destinations that qualify as candidates to be summarized route destinations that qualify as candidates to be summarized
resulting in route information reduction. resulting in route information reduction.
To take an example, if there are multiple gateways offering routes to To take an example, if there are multiple gateways offering routes to
an E.164 destination "408" but with possibly different attributes an E.164 destination "408" but with possibly different attributes
(Eg: Carrier), the LS/Proxy can combine these to form one route for (Eg: Carrier), the LS/Proxy can combine these to form one route for
"408" but representing the attribute information collectively. This "408" but representing the attribute information collectively. This
process is Consolidation process is Consolidation
If, for example, the LS/Proxy receives routes for 4080, 4081, 4082, If, for example, the LS/Proxy receives routes for 4080, 4081, 4082,
... 4089 from amongst a set of gateways, it could aggregate these ... 4089 from amongst a set of gateways, it could aggregate these
different candidate routes to have a summarized route destination different candidate routes to have a summarized route destination
"408" with each of the attributes computed using the Aggregation "408" with each of the attributes computed using the Aggregation
procedures defined in the TRIP RFC. procedures defined in the TRIP.
4. Security Considerations 5. Security Considerations
The Security considerations defined in the TRIP RFC [4] apply to The Security considerations defined in the TRIP [4] apply to TGREP
TGREP sessions between Gateways and TGREP Receivers sessions between Gateways and TGREP Receivers (TRIP LS).
5. IANA Considerations The security mechanism for the peering session between TGREP GW and a
TRIP LS, in an IP network, is IPsec [6]. IPsec uses two protocols to
provide traffic security: Authentication Header (AH) [7] and
Encapsulating Security Payload (ESP) [8].
- The Attribute Type Codes for the new attributes: The AH header affords data origin authentication, connectionless
AvailableCircuits, TotalCircuitCapacity, CallSuccess, Prefix, integrity and optional anti-replay protection of messages passed
TrunkGroup and Carrier described in Sections 3.1, 3.2, 3.3, 3.4, between the peer LSs. The ESP header provides origin authentication,
3.5 and 3.6 above, respectively, are to be assigned by IANA. connectionless integrity, anti-replay protection, and confidentiality
- The Address Family Codes for the new address families: TrunkGroup of messages.
and Carrier described in Section 3.7, are to be assigned by IANA.
Implementations of the protocol defined in this document employing
the ESP header SHALL comply with section 5 of [8], which defines a
minimum set of algorithms for integrity checking and encryption.
Similarly, implementations employing the AH header SHALL comply with
section 5 of [7], which defines a minimum set of algorithms for
integrity checking using manual keys.
Implementations SHOULD use IKE [9] to permit more robust keying
options. Implementations employing IKE SHOULD support authentication
with RSA signatures and RSA public key encryption.
A Security Association (SA) [6] is a simplex "connection" that
affords security services to the traffic carried by it. Security
services are afforded to a SA by the use of AH, or ESP, but not both.
Two types of SAs are defined: transport mode and tunnel mode [12]. A
transport mode SA is a security association between two hosts, and is
appropriate for protecting the TRIP session between two peer LSs.
6. IANA Considerations
Both TRIP[4] and TGREP share the same IANA registry for Capabilities, Both TRIP[4] and TGREP share the same IANA registry for Capabilities,
Attributes, Address Families, and Application Protocols Attributes, Address Families, and Application Protocols.
6. Changes since draft-ietf-iptel-tgrep-03.txt 6.1. Attribute Codes
The Attribute Type Codes to be assigned for the new attributes
defined in this document are listed below:
| Code Attribute Reference
| ---- --------- ---------
| 13 TotalCircuitCapacity [RFCXXXX]
| 14 AvailableCircuits [RFCXXXX]
| 15 CallSuccess [RFCXXXX]
| 16 E.164 Prefix [RFCXXXX]
| 17 Pentadecimal Routing Number Prefix [RFCXXXX]
| 18 Decimal Routing Number Prefix [RFCXXXX]
| 19 TrunkGroup [RFCXXXX]
| 19 Carrier [RFCXXXX]
[NOTE TO RFC-ED: please replace XXXX with the rfc number of this
specification ]
6.2. Address Family Codes
The following subsections show the codes to be assigned for the two
new address families introduced in this document
6.2.1. TrunkGroup Address Family
| Code Address Family Reference
| ---- -------------- ---------
| 4 TrunkGroup [RFCXXXX]
[NOTE TO RFC-ED: please replace XXXX with the rfc number of this
specification ]
6.2.2. Carrier Address Family
| Code Address Family Reference
| ---- -------------- ---------
| 5 Carrier [RFCXXXX]
[NOTE TO RFC-ED: please replace XXXX with the rfc number of this
specification ]
7. Change history
[[NOTE TO RFC-ED: Please remove this section prior to publication]]
7.1. Changes since draft-ietf-iptel-tgrep-03.txt
- No change in content. Releasing a new revision for renewal of - No change in content. Releasing a new revision for renewal of
draft draft.
7. Changes since draft-ietf-iptel-tgrep-02.txt 7.2. Changes since draft-ietf-iptel-tgrep-02.txt
- No change in content. Releasing a new revision for renewal of - No change in content. Releasing a new revision for renewal of
draft draft.
8. Changes since draft-ietf-iptel-tgrep-01.txt 7.3. Changes since draft-ietf-iptel-tgrep-01.txt
- Added a "Security Considerations" Section to the document - Added a "Security Considerations" Section to the document.
- Strengthened the text under "LS/Proxy Behavior" regarding - Strengthened the text under "LS/Proxy Behavior" regarding
Consolidation and Aggregation with additional examples for better Consolidation and Aggregation with additional examples for better
clarity clarity.
- Removed the section "Other Attributes" including its subsection - Removed the section "Other Attributes" including its subsection
on the "Pricing" attribute on the "Pricing" attribute.
- Modified the definition of Carrier in the "Carrier attribute" and - Modified the definition of Carrier in the "Carrier attribute" and
"TrunkGroup and Carrier Address Families" sections respectively "TrunkGroup and Carrier Address Families" sections respectively.
- Rectified the section number references in the "IANA - Rectified the section number references in the "IANA
Considerations" Section Considerations" Section.
- Strengthened the text in the attribute sections regarding - Strengthened the text in the attribute sections regarding
dissemination of attributes received on TGREP dissemination of attributes received on TGREP.
- Updated the "References" section - Updated the "References" section.
- Corrected typos, nits, grammatical errors, and language of the - Corrected typos, nits, grammatical errors, and language of the
text throughout the document based on feedback from the iptel text throughout the document based on feedback from the iptel
community community.
9. Changes since draft-ietf-iptel-tgrep-00.txt 7.4. Changes since draft-ietf-iptel-tgrep-00.txt
- Added recommendations for AvailableCircuits and CallSuccess - Added recommendations for AvailableCircuits and CallSuccess
attributes. attributes.
- Updated Carrier Attribute with ASCII syntax. - Updated Carrier Attribute with ASCII syntax.
- Removed thresholding scheme description. - Removed thresholding scheme description.
- Updated author addresses. - Updated author addresses.
10. Changes since draft-ietf-iptel-trip-gw-00.txt 7.5. Changes since draft-ietf-iptel-trip-gw-00.txt
- Changed title of the document to TGREP (Telephony Gateway - Changed title of the document to TGREP (Telephony Gateway
REgistration Protocol) REgistration Protocol).
- Changed name of protocol described in this document to TGREP - Changed name of protocol described in this document to TGREP.
- Changed Abstract and Introduction sections to position TGREP as - Changed Abstract and Introduction sections to position TGREP as
an auxiliary protocol to TRIP (as opposed to a "subset" of TRIP) an auxiliary protocol to TRIP (as opposed to a "subset" of TRIP).
- Modified the section on LS/Proxy Behavior including the diagram - Modified the section on LS/Proxy Behavior including the diagram.
- Added an additional example to the Route Consolidation section - Added an additional example to the Route Consolidation section.
- Changed the format of Carrier (both as an attribute and as an AF) - Changed the format of Carrier (both as an attribute and as an AF)
to accomodate representation of Country codes in association with to accommodate representation of Country codes in association
CICs. with CICs.
- Updated text to allow Carrier attribute in TrunkGroup address - Updated text to allow Carrier attribute in TrunkGroup address
family and TrunkGroup attribute in Carrier address family. family and TrunkGroup attribute in Carrier address family.
11. Changes since -03 7.6. Changes since -03
- Removed Carrier-Trunkgroup attribute and address family and - Removed Carrier-Trunkgroup attribute and address family and
references to it. references to it.
- Added Terminology and Definitions section. - Added Terminology and Definitions section.
- Updated CallSuccess attribute. - Updated CallSuccess attribute.
- Added Prefix attribute. - Added Prefix attribute.
- Added Carrier attribute. - Added Carrier attribute.
- Added TrunkGroup attribute. - Added TrunkGroup attribute.
- Added TrunkGroup Address Family. - Added TrunkGroup Address Family.
- Added Carrier Address Family. - Added Carrier Address Family.
- Added some more references. - Added some more references.
12. Changes since -02 7.7. Changes since -02
- Removed the requirements section. - Removed the requirements section.
- Discussed the motivation for introducing Carrier information into - Discussed the motivation for introducing Carrier information into
TRIP. TRIP.
- Defined a new attribute for the E.164 address family. - Defined a new attribute for the E.164 address family.
- Defined a new address family for CarrierCode-TrunkGroup - Defined a new address family for CarrierCode-TrunkGroup
combination . combination .
- Defined new attributes to advertise dynamic gateway - Defined new attributes to advertise dynamic gateway
characteristics like resource availability, and call success characteristics like resource availability, and call success
rate. rate.
- Added as section to validate the TGREP solution against the - Added as section to validate the TGREP solution against the
requirements in [7]. requirements in [7].
13. Changes since -01 7.8. Changes since -01
- Added requirements. - Added requirements.
- Added more formal analysis of REGISTER and added analysis of SLP. - Added more formal analysis of REGISTER and added analysis of SLP.
- Removed circuit capacity attribute. - Removed circuit capacity attribute.
14. Changes since -00 7.9. Changes since -00
- Added text to stress the value of this proposal for managing a - Added text to stress the value of this proposal for managing a
gateway cluster. gateway cluster.
- Added attributes for circuit capacity and DSP capacity. - Added attributes for circuit capacity and DSP capacity.
- Added section on LS operation, discussing aggregation issue. - Added section on LS operation, discussing aggregation issue.
Authors' Addresses 8. Acknowledgments
Manjunath Bangalore
Cisco Systems
Mail Stop SJC-21/2/2
170 W. Tasman Drive
San Jose, CA 95134
email: manjax@cisco.com
Rajneesh Kumar
Cisco Systems
Mail Stop SJC-14/4/2
170 W. Tasman Drive
San Jose, CA 95134
email: rajneesh@cisco.com
Jonathan Rosenberg
dynamicsoft
72 Eagle Rock Avenue
First Floor
East Hanover, NJ 07936
email: jdrosen@dynamicsoft.com
Hussein F. Salama
Cisco Systems
Mail Stop CAI1
135 Abdel Aziz Fahmy Street
2nd Floor Apartment #3, Heliopolis
Cairo, Egypt
email: hsalama@cisco.com
Dhaval N. Shah
Cisco Systems
Mail Stop SJC-06/4/3
170 W. Tasman Drive
San Jose, CA 95134
email: dhaval@cisco.com
Acknowledgments
We wish to thank David Oran, Anirudh Sahoo, Kevin McDermott, Jon We wish to thank David Oran, Anirudh Sahoo, Kevin McDermott, Jon
Peterson, Li Li and Bob Penfield for their insightful comments and Peterson, Li Li and Bob Penfield for their insightful comments and
suggestions. suggestions.
References 9. References
9.1. Normative References
[1] Bradner, S., "Keywords for use in RFCs to Indicate Requirement [1] Bradner, S., "Keywords for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[2] M. Handley, H. Schulzrinne, E. Schooler, and J. Rosenberg, "SIP: [2] M. Handley, H. Schulzrinne, E. Schooler, and J. Rosenberg, "SIP:
session initiation protocol," Request for Comments 3261, Internet session initiation protocol," Request for Comments 3261, Internet
Engineering Task Force, Mar. 1999. Engineering Task Force, Mar. 1999.
[3] E. Guttman, C. Perkins, J. Veizades, and M. Day, "Service [3] E. Guttman, C. Perkins, J. Veizades, and M. Day, "Service
location protocol, version 2," Request for Comments 2608, Internet location protocol, version 2," Request for Comments 2608, Internet
Engineering Task Force, June 1999. Engineering Task Force, June 1999.
[4] J. Rosenberg, H. Salama, and M. Squire, "Telephony routing over [4] J. Rosenberg, H. Salama, and M. Squire, "Telephony routing over
IP (TRIP)," Request for Comments 3219, Internet Engineering Task IP (TRIP)," Request for Comments 3219, Internet Engineering Task
Force, January 2002. Force, January 2002.
[5] J. Rosenberg and H. Schulzrinne, "A framework for telephony [5] J. Rosenberg and H. Schulzrinne, "A framework for telephony
routing over IP," Request for Comments 2871, Internet Engineering routing over IP," Request for Comments 2871, Internet Engineering
Task Force, June 2000. Task Force, June 2000.
[6] J. Rosenberg, "Requirements for Gateway Registration," Internet [6] Kent, S. and R. Atkinson, "Security Architecture for the
Internet Protocol", RFC 2401, November 1998.
[7] Kent, S. and R. Atkinson, "IP Authentication Header", RFC 2402,
November 1998.
[8] Kent, S. and R. Atkinson, "IP Encapsulating Security Payload
(ESP)", RFC 2406, November 1998.
[9] Harkins, D. and D. Carrel, "The Internet Key Exchange (IKE)",
RFC 2409, November 1998.
9.2. Informative References
[10] J. Rosenberg, "Requirements for Gateway Registration," Internet
Draft, Internet Engineering Task Force, Nov. 2001. Work in progress. Draft, Internet Engineering Task Force, Nov. 2001. Work in progress.
[7] ITU-T List of ITU Carrier Codes (published periodically in the [11] ITU-T List of ITU Carrier Codes (published periodically in the
ITU-T Operational Bulletin). ITU-T Operational Bulletin).
[8] J. Peterson, "An Architecture for Gateway Registration Based on [12] J. Peterson, "An Architecture for Gateway Registration Based on
Trunk Groups," Internet Draft, Internet Engineering Task Force, Feb. Trunk Groups," Internet Draft, Internet Engineering Task Force, Feb.
2002. Work in progress. 2002. Work in progress.
Authors' Addresses
Manjunath Bangalore
Cisco Systems Inc.
Mail Stop SJC-21/2/2
170 W. Tasman Drive
San Jose, CA 95134
email: manjax@cisco.com
Rajneesh Kumar
Cisco Systems Inc.
Mail Stop SJC-14/4/2
170 W. Tasman Drive
San Jose, CA 95134
email: rajneesh@cisco.com
Jonathan Rosenberg
Cisco Systems Inc.
Mail Stop PPY02/2
600 Lanidex Plaza
Parsippany
NJ 07054
email: jdrosen@cisco.com
Hussein F. Salama
Cisco Systems Inc.
Mail Stop CAI1
135 Abdel Aziz Fahmy Street
2nd Floor Apartment #3, Heliopolis
Cairo, Egypt
email: hsalama@cisco.com
Dhaval N. Shah
Cisco Systems Inc.
Mail Stop SJC-06/4/3
170 W. Tasman Drive
San Jose, CA 95134
email: dhaval@cisco.com
Intellectual Property Statement Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
skipping to change at page 28, line 31 skipping to change at page 33, line 20
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 AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement Copyright Statement
Copyright (C) The Internet Society (2004). This document is subject Copyright (C) The Internet Society (2005). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights. except as set forth therein, the authors retain all their rights.
Acknowledgment Acknowledgment
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is currently provided by the
Internet Society. Internet Society.
 End of changes. 

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