draft-ietf-speermint-architecture-04.txt   draft-ietf-speermint-architecture-05.txt 
Speermint Working Group R. Penno Speermint Working Group R. Penno
Internet Draft Juniper Networks Internet Draft Juniper Networks
Intended status: Informational D. Malas Intended status: Informational D. Malas
Expires: January 2008 Level 3 Expires: August 2008 Level 3
S. Khan S. Khan
Comcast Comcast
A. Uzelac A. Uzelac
Global Crossing Global Crossing
August 10, 2007 February 24, 2008
SPEERMINT Peering Architecture SPEERMINT Peering Architecture
draft-ietf-speermint-architecture-04 draft-ietf-speermint-architecture-05
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that By submitting this Internet-Draft, each author represents that
any applicable patent or other IPR claims of which he or she is any applicable patent or other IPR claims of which he or she is
aware have been or will be disclosed, and any of which he or she aware have been or will be disclosed, and any of which he or she
becomes aware will be disclosed, in accordance with Section 6 of becomes aware will be disclosed, in accordance with Section 6 of
BCP 79. BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six
and may be updated, replaced, or obsoleted by other documents at any months and may be updated, replaced, or obsoleted by other documents
time. It is inappropriate to use Internet-Drafts as reference at any time. It is inappropriate to use Internet-Drafts as
material or to cite them other than as "work in progress." reference material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html http://www.ietf.org/shadow.html
This Internet-Draft will expire on January 2008. This Internet-Draft will expire on January 2008.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2008).
Abstract Abstract
This document defines the SPEERMINT peering architecture, its This document defines the SPEERMINT peering architecture, its
functional components and peering interface functions. It also functional components and peering interface functions. It also
describes the steps taken to establish a session between two peering describes the steps taken to establish a session between two peering
domains in the context of the functions defined. domains in the context of the functions defined.
Conventions used in this document Conventions used in this document
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]
Table of Contents Table of Contents
1. Introduction...................................................3 1. Introduction...................................................3
2. Network Context................................................3 2. Network Context................................................4
3. Procedures.....................................................6 3. Procedures.....................................................5
4. Reference SPEERMINT Architecture...............................6 4. Reference SPEERMINT Architecture...............................6
5. Peer Function Examples.........................................8 5. Peer Function Examples.........................................8
5.1. The Location Function (LF) of an Initiating Provider......8 5.1. The Location Function (LF) of an Initiating Provider......8
5.1.1. Target address analysis..............................8 5.1.1. Target address analysis..............................8
5.1.2. User ENUM Lookup.....................................9 5.1.2. User ENUM Lookup.....................................9
5.1.3. Carrier ENUM lookup.................................10 5.1.3. Carrier ENUM lookup.................................10
5.1.4. Routing Table.......................................10 5.1.4. Routing Table.......................................10
5.1.5. SIP DNS Resolution..................................10 5.1.5. SIP DNS Resolution..................................10
5.1.6. SIP Redirect Server.................................11 5.1.6. SIP Redirect Server.................................11
5.2. The Location Function (LF) of a Receiving Provider.......11 5.2. The Location Function (LF) of a Receiving Provider.......11
5.2.1. Publish ENUM records................................11 5.2.1. Publish ENUM records................................11
5.2.2. Publish SIP DNS records.............................11 5.2.2. Publish SIP DNS records.............................11
5.2.3. Subscribe Notify....................................11 5.2.3. Subscribe Notify....................................11
5.3. Signaling Function (SF)..................................11 5.3. Signaling Function (SF)..................................11
5.4. The Signaling Function (SF) of an Initiating Provider....12 5.4. The Signaling Function (SF) of an Initiating Provider....12
5.4.1. Setup TLS connection................................12 5.4.1. Setup TLS connection................................12
5.4.2. IPSec...............................................12 5.4.2. IPSec...............................................12
5.4.3. Co-Location.........................................13 5.4.3. Co-Location.........................................12
5.4.4. Send the SIP request................................13 5.4.4. Send the SIP request................................12
5.5. The Signaling Function (SF) of an Initiating Provider....14 5.5. The Signaling Function (SF) of an Initiating Provider....14
5.5.1. Verify TLS connection...............................14 5.5.1. Verify TLS connection...............................14
5.5.2. Receive SIP requests................................14 5.5.2. Receive SIP requests................................14
5.6. Media Function (MF)......................................15 5.6. Media Function (MF)......................................15
5.7. Policy Considerations....................................15 5.7. Policy Considerations....................................15
6. Call Control and Media Control Deployment Options.............16 6. Call Control and Media Control Deployment Options.............16
7. Address space considerations..................................18 7. Address space considerations..................................17
8. Security Considerations.......................................18 8. Security Considerations.......................................17
9. IANA Considerations...........................................18 9. IANA Considerations...........................................18
10. Acknowledgments..............................................18 10. Acknowledgments..............................................18
11. References...................................................19 11. References...................................................19
11.1. Normative References....................................19 11.1. Normative References....................................19
11.2. Informative References..................................20 11.2. Informative References..................................20
Author's Addresses...............................................21 Author's Addresses...............................................21
Intellectual Property Statement..................................21 Intellectual Property Statement..................................21
Disclaimer of Validity...........................................22 Disclaimer of Validity...........................................22
1. Introduction 1. Introduction
The objective of this document is to define a reference peering The objective of this document is to define a reference peering
architecture in the context of Session PEERing for Multimedia architecture in the context of Session PEERing for Multimedia
INTerconnect (SPEERMINT). In this process, we define the peering INTerconnect (SPEERMINT). In this process, we define the peering
reference architecture (reference, for short), it's functional reference architecture (reference, for short), it's functional
components, and peering interface functions from the perspective of a components, and peering interface functions from the perspective of
real-time communications (Voice and Multimedia) IP Service provider a SIP [3] Service provider's (SSP) network.
network.
This architecture allows the interconnection of two service providers This architecture allows the interconnection of two SSPs in layer 5
in layer 5 peering as defined in the SPEERMINT Requirements [13] and peering as defined in the SPEERMINT Requirements [13] and
Terminology [12] documents for the purpose SIP-based voice and Terminology [12] documents.
multimedia traffic.
Layer 3 peering is outside the scope of this document. Hence, the Layer 3 peering is outside the scope of this document. Hence, the
figures in this document do not show routers so that the focus is on figures in this document do not show routers so that the focus is on
Layer 5 protocol aspects. Layer 5 protocol aspects.
This document uses terminology defined in the SPEERMINT Terminology This document uses terminology defined in the SPEERMINT Terminology
document [12]. document [12], so the reader should be familiar with all the terms
defined there.
2. Network Context 2. Network Context
Figure 1 shows an example network context. Two SIP providers can form Figure 1 shows an example network context. Two SSPs can form a Layer
a Layer 5 peer over either the public Internet or private Layer 3 5 peering over either the public Internet or private Layer3
networks. In addition, two or more providers may form a SIP (Layer 5) networks. In addition, two or more providers may form a SIP (Layer
federation [17] on either the public Internet or private Layer 3 5) federation [13] on either the public Internet or private Layer 3
networks. This document does not make any assumption whether the SIP networks. This document does not make any assumption whether the SIP
providers directly peer to each other or through Layer 3 transit providers directly peer to each other or through Layer 3 transit
network as per use case of [16]. network as per use case of [16].
Note that Figure 1 allows for the following potential SPEERMINT Note that Figure 1 allows for the following potential SPEERMINT
peering scenarios: peering scenarios:
o Enterprise to Enterprise across the public Internet o Enterprise to Enterprise across the public Internet
o Enterprise to Service Provider across the public Internet o Enterprise to SSP across the public Internet
o Service Provider to Service Provider across the public Internet o SSP to SSP across the public Internet
o Enterprise to enterprise across a private Layer 3 network o Enterprise to enterprise across a private Layer 3 network
o Enterprise to Service Provider across a private Layer 3 network o Enterprise to SSP across a private Layer 3 network
o Service Provider to Service Provider across a private Layer 3 o SSP to SSP across a private Layer 3 network
network
The members of a federation may jointly use a set of functions such The members of a federation may jointly use a set of functions such
as location peering function, application function, subscriber as location function, signaling function, media function, ENUM
database function, SIP proxies, and/or functions that synthesize database or SIP Registrar, SIP proxies, and/or functions that
various SIP and non-SIP based applications. Similarly, two providers synthesize various SIP and non-SIP based applications. Similarly,
may jointly use a set of peering functions. The federation functions two SSPs may jointly use a set of functions. The functions can be
or the peering functions can be either public or private. either public or private.
+-------------------+ +-------------------+
| |
| Public | | Public |
| Peering Function | | Peering |
| or | | Function |
| Public | | |
|Federation Function|
+-------------------+ +-------------------+
| |
----- -----
+-----------+ / \ +-----------+ +-----------+ / \ +-----------+
|Enterprise | -- -- |Enterprise | |Enterprise | -- -- |Enterprise |
|Provider A |-----------/ \-----------|Provider B | |Provider A |-----------/ \-----------|Provider B |
+-----------+ -- -- +-----------+ +-----------+ -- -- +-----------+
/ Public \ / Public \
| Internet | | Internet |
\ (Layer 3) / \ (Layer 3) /
+-----------+ -- -- +-----------+ +-----------+ -- -- +-----------+
|Service |-----------\ /-----------|Service | |Service |-----------\ /-----------|Service |
|Provider C | -- -- |Provider D | |Provider C | -- -- |Provider D |
+-----------+ \_____/ +-----------+ +-----------+ \_____/ +-----------+
| Layer 3 Peering | Layer 3 Peering
| Point (out of scope) | Point (out of scope)
----- -----
+-----------+ / \ +-----------+ +-----------+ / \ +-----------+
|Enterprise | -- -- |Enterprise | |Enterprise | -- -- |Enterprise |
|Provider E |-----------/ \-----------|Provider F | |Provider E |-----------/ \-----------|Provider F |
+-----------+ -- Service -- +-----------+ +-----------+ -- Private -- +-----------+
/ Provider \ / Network \
| Private | | (Layer 3) |
\ Network / \ /
+-----------+ -- (Layer 3) -- +-----------+ +-----------+ -- -- +-----------+
|Service |-----------\ /-----------|Service | | SSP G |-----------\ /-----------| SSP H |
|Provider G | -- -- |Provider H | | | -- -- | |
+-----------+ \____/ +-----------+ +-----------+ \____/ +-----------+
| |
+-------------------+ +-------------------+
| Private | | Private |
| Peering Function | | SIP |
| or | | Peering |
|Federation Function| | |
+-------------------+ +-------------------+
Figure 1: SPEERMINT Network Context Figure 1: SPEERMINT Network Context
3. Procedures 3. Procedures
This document assumes that a call from an end user in the initiating This document assumes that a call from a UAC end user in the
peer goes through the following steps to establish a call to an end initiating peer's network goes through the following steps to
user in the receiving peer: establish a call to a UAS in the receiving peer's network:
1. The analysis of a target address. 1. The analysis of a target address.
a. If the target address represents an intra-VSP resource, a. If the target address represents an intra-SSP resource,
we go directly to step 4. we go directly to step 4.
2. the discovery of the receiving peering point address, 2. the discovery of the receiving peering point address,
3. the enforcement of authentication and other policy, 3. the enforcement of authentication and potentially other
policies,
4. the discovery of end user address, 4. the discovery of the UAS,
5. the routing of SIP messages, 5. the routing of SIP messages,
6. the session establishment, 6. the session establishment,
7. the transfer of media, 7. the transfer of media which could include voice, video, text
and others,
8. and the session termination. 8. and the session termination.
4. Reference SPEERMINT Architecture 4. Reference SPEERMINT Architecture
Figure 2 depicts the SPEERMINT architecture and logical functions Figure 2 depicts the SPEERMINT architecture and logical functions
that form the peering between two SIP service providers. that form the peering between two SSPs.
+------+ +------+
| DNS, | | DNS, |
+---------| Db, |---------+ +---------->| Db, |<---------+
| | etc | | | | etc | |
| +------+ | | +------+ |
| | | |
--------------- --------------- ------|-------- -------|-------
/ \ / \ / v \ / v \
| | | | | +--LUF-+ | | +--LUF-+ |
| | | | | | | | | | | |
| +------+ | | +------+ | | | | | | | | |
| | DNS, | | | | DNS, | | | | | | | | | |
| | Db, | | | | Db, | |
| | etc | | | | etc | |
| +------+ | | +------+ | | +------+ | | +------+ |
| | | |
| | | |
| +---SF--+ +---SF--+ |
| | | | | | | | | | | |
| | | | | |
| v | | v |
| +--LRF-+ | | +--LRF-+ |
| | | | | | | |
| | | | | | | |
| | | | | | | |
| +------+ | | +------+ |
| \ | | / |
| `. | | / |
| \ | | .' |
| `. +---SF--+ +---SF--+ / |
| \| | | | / |
| | SBE | | SBE | | | | SBE | | SBE | |
| Originating | | | | Terminating | | Originating | | | | Target |
| +---SF--+ +---SF--+ | | +---SF--+ +---SF--+ |
| Domain | | Domain | | SSP | | SSP |
| +---MF--+ +---MF--+ | | +---MF--+ +---MF--+ |
| SSP | | | | SSP | | | | | | |
| | DBE | | DBE | | | | DBE | | DBE | |
| | | | | | | | | | | |
| +---MF--+ +---MF--+ | | +---MF--+ +---MF--+ |
| | | |
| +----LF---+ +----LF---+ |
| +-LF--|----+ | | +----|--LS-+ |
| | | | | | | | | |
| | SM | | LS | | LS | | SM | |
| | | | | | | | | |
| | +----|----+ +----|----+ | |
| +----------+| |+----------+ |
| | | |
| | | |
\ / \ / \ / \ /
--------------- --------------- --------------- ---------------
Figure 2: Reference SPEERMINT Architecture Figure 2: Reference SPEERMINT Architecture
The procedures presented in Chapter 3 are implemented by a set of The procedures presented in Chapter 3 are implemented by a set of
peering functions: peering functions:
o Location Function (LF): Purpose is to develop Session The Look-Up Function (LUF) provides a mechanism for determining for
Establishment Data (SED) by discovering the Signaling Function a given request the target domain to which the request should be
(SF) and the end user's reachable host (IP address and port). The routed.
location function is distributed across the Location Server (LS)
and Session Manager (SM).
o Signaling Function (SF): Purpose is to perform SIP call routing, The Location Routing Function (LRF) determines for the target domain
to optionally perform termination and re-initiation of call, to of a given request the location of the SF in that domain and
optionally develops other SED required to route the request to that
domain.
Location Function (LF): The Location functions is composed of the
LUF and LRF functions
Signaling Function (SF): Purpose is to perform SIP call routing, to
optionally perform termination and re-initiation of call, to
optionally implement security and policies on SIP messages, and to optionally implement security and policies on SIP messages, and to
assist in discovery/exchange of parameters to be used by the Media assist in discovery/exchange of parameters to be used by the Media
Function (MF). The signaling function is located within the Function (MF).
Signaling Path Border Element (SBE)
o Media Function (MF): Purpose is to perform media related function Media Function (MF): Purpose is to perform media related function
such as media transcoding and media security implementation such as media transcoding and media security implementation between
between two SIP providers. The media function is located within two SIP providers.
the Data Path Border Element (DBE).
The intention of defining these functions is to provide a framework The intention of defining these functions is to provide a framework
for design segmentation and allow each one to evolve separately. for design segmentation and allow each one to evolve independently.
5. Peer Function Examples 5. Peer Function Examples
This section describes the peering functions in more detail and This section describes the functions in more detail and provides
provides some examples on the role they would play in a SIP call in a some examples on the role they would play in a SIP call in a Layer 5
Layer 5 peering scenario. peering scenario.
Some of the information in the chapter is taken from [14]. Some of the information in the chapter is taken from [14] and is put
here for continuity purposes.
5.1. The Location Function (LF) of an Initiating Provider 5.1. The Location Function (LF) of an Initiating Provider
Purpose is to develop Session Establishment Data (SED) [12] by Purpose is to determine the SF of the target domain of a given
discovering the Signaling Function (SF), and end user's reachable request and optionally develop Session Establishment Data (SED)
host (IP address and host). The LF of an Initiating provider analyzes [12]. The LF of an Initiating SSP analyzes target address and
target address and discovers the next hop signaling function (SF) in discovers the next hop signaling function (SF) in a peering
a peering relationship using DNS, SIP Redirect Server, or a relationship using the Look-Up Function. The resource to determine
functional equivalent database. the SF of the target domain might be provided by a third-party as in
the assisted-peering case.
5.1.1. Target address analysis 5.1.1. Target address analysis
When the initiating provider receives a request to communicate, the When the initiating SSP receives a request to communicate, it
initiating provider analyzes the target state data to determine analyzes the target state data to determine whether the call needs
whether the call needs to be terminated internal or external to its to be terminated internal or external to its network. The analysis
network. The analysis method is internal to the provider's policy; method is internal to the SSP; thus, outside the scope of SPEERMINT.
thus, outside the scope of SPEERMINT. Note that the peer is free to Note that the SSP is free to consult any manner of private data
consult any manner of private data sources to make this sources to make this determination.
determination.
If the target address does not represent a resource inside the If the target address does not represent a resource inside the
initiating peer's administrative domain or federation of domains, the initiating SSP's administrative domain or federation of domains, the
initiating provider resolves the call routing data by using the initiating SSP resolves the call routing data by using the Location
Location Function (LF). Examples of the LF are the functions of ENUM, Function (LF).
Routing Table, SIP DNS, and SIP Redirect Server.
If the request to communicate is for an im: or pres: URI type, the If the request to communicate is for an im: or pres: URI type, the
initiating peer follows the procedures in [8]. If the highest initiating peer follows the procedures in [8]. If the highest
priority supported URI scheme is sip: or sips:, the initiating peer priority supported URI scheme is sip: or sips:, the initiating peer
skips to SIP DNS resolution in Section 5.1.5. Likewise, if the target skips to SIP DNS resolution in Section 5.1.5. Likewise, if the
address is already a sip: or sips: URI in an external domain, the target address is already a sip: or sips: URI in an external domain,
initiating peer skips to SIP DNS resolution in Section 5.1.5. the initiating peer skips to SIP DNS resolution in Section 5.1.5.
If the target address corresponds to a specific E.164 address, the If the target address corresponds to a specific E.164 address, the
peer may need to perform some form of number plan mapping according peer may need to perform some form of number plan mapping according
to local policy. For example, in the United States, a dial string to local policy. For example, in the United States, a dial string
beginning "011 44" could be converted to "+44", or in the United beginning "011 44" could be converted to "+44", or in the United
Kingdom "00 1" could be converted to "+1". Once the peer has an Kingdom "00 1" could be converted to "+1". Once the peer has an
E.164 address, it can use ENUM. E.164 address, it can use ENUM.
5.1.2. User ENUM Lookup 5.1.2. User ENUM Lookup
If an external E.164 address is the target, the initiating peer If an external E.164 address is the target, the initiating peer
consults the public "User ENUM" rooted at e164.arpa, according to the consults the public "User ENUM" rooted at e164.arpa, according to
procedures described in RFC 3761. The peer MUST query for the the procedures described in RFC 3761. The peer MUST query for the
"E2U+sip" enumservice as described in RFC 3764 [11], but MAY check "E2U+sip" enumservice as described in RFC 3764 [11], but MAY check
for other enumservices. The initiating peer MAY consult a cache or for other enumservices. The initiating peer MAY consult a cache or
alternate representation of the ENUM data rather than actual DNS alternate representation of the ENUM data rather than actual DNS
queries. Also, the peer MAY skip actual DNS queries if the queries. Also, the peer MAY skip actual DNS queries if the
initiating peer is sure that the target address country code is not initiating peer is sure that the target address country code is not
represented in e164.arpa. If a sip: or sips: URI is chosen the peer represented in e164.arpa. If a sip: or sips: URI is chosen the peer
skips to Section 5.1.5. skips to Section 5.1.5.
If an im: or pres: URI is chosen for based on an "E2U+im" [10] or If an im: or pres: URI is chosen for based on an "E2U+im" [10] or
"E2U+pres" [9] enumserver, the peer follows the procedures for "E2U+pres" [9] enumserver, the peer follows the procedures for
resolving these URIs to URIs for specific protocols such a SIP or resolving these URIs to URIs for specific protocols such a SIP or
XMPP as described in the previous section. XMPP as described in the previous section.
5.1.3. Carrier ENUM lookup 5.1.3. Infrastructure ENUM lookup
Next the initiating peer checks for a carrier-of-record in a carrier Next the initiating peer checks for a carrier-of-record in a carrier
ENUM domain according to the procedures described in [12]. As in the ENUM domain according to the procedures described in [12]. As in
previous step, the peer MAY consult a cache or alternate the previous step, the peer MAY consult a cache or alternate
representation of the ENUM data in lieu of actual DNS queries. The representation of the ENUM data in lieu of actual DNS queries. The
peer first checks for records for the "E2U+sip" enumservice, then for peer first checks for records for the "E2U+sip" enumservice, then
the "E2U+pstn" enumservice as defined in [21]. If a terminal record for the "E2U+pstn" enumservice as defined in [21]. If a terminal
is found with a sip: or sips: URI, the peer skips to Section 5.1.5, record is found with a sip: or sips: URI, the peer skips to Section
otherwise the peer continues processing according to the next 5.1.5, otherwise the peer continues processing according to the next
section. section.
5.1.4. Routing Table 5.1.4. Routing Table
If there is no user ENUM records and the initiating peer cannot If there is no user ENUM records and the initiating peer cannot
discover the carrier-of-record or if the initiating peer cannot reach discover the carrier-of-record or if the initiating peer cannot
the carrier-of-record via SIP peering, the initiating peer still reach the carrier-of-record via SIP peering, the initiating peer
needs to deliver the call to the PSTN or reject the call. Note that still needs to deliver the call to the PSTN or reject it. Note that
the initiating peer MAY still sends the call to another provider for the initiating peer MAY still forward the call to another SSP for
PSTN gateway termination by prior arrangement using a routing table. PSTN gateway termination by prior arrangement using the routing
table.
If so, the initiating peer rewrites the Request-URI to address the If so, the initiating peer rewrites the Request-URI to address the
gateway resource in the target provider's domain and MAY forward the gateway resource in the target SSP's domain and MAY forward the
request on to that provider using the procedures described in the request on to that SSP using the procedures described in the
remainder of these steps. remainder of these steps.
5.1.5. SIP DNS Resolution 5.1.5. SIP DNS Resolution
Once a sip: or sips: in an external domain is selected as the target, Once a sip: or sips: in an external domain is selected as the
the initiating peer MAY apply local policy to decide whether target, the initiating peer MAY apply local policy to decide whether
forwarding requests to the target domain is acceptable. If so, the forwarding requests to the target domain is acceptable. If so, the
initiating peer uses the procedures in RFC 3263 [6] Section 4 to initiating peer uses the procedures in RFC 3263 [4] Section 4 to
determine how to contact the receiving peer. To summarize the RFC determine how to contact the receiving peer. To summarize the RFC
3263 procedure: unless these are explicitly encoded in the target 3263 procedure: unless these are explicitly encoded in the target
URI, a transport is chosen using NAPTR records, a port is chosen 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. using SRV records, and an address is chosen using A or AAAA records.
Note that these are queries of records in the global DNS. Note that these are queries of records in the global DNS.
When communicating with a public external peer, entities compliant to When communicating with a public external peer, entities compliant
this document MUST only select a TLS-protected transport for to this document MUST only select a TLS-protected transport for
communication from the initiating peer to the receiving peer. Note communication from the initiating peer to the receiving peer. Note
that this is a single-hop requirement. Either peer MAY insist on that this is a single-hop requirement. Either peer MAY insist on
using a sips: URI which asserts that each hop is TLS-protected, but using a sips: URI which asserts that each hop is TLS-protected, but
this document does not require protection over each hop. this document does not require protection over each hop.
5.1.6. SIP Redirect Server 5.1.6. SIP Redirect Server
A SIP Redirect Server may help in resolving current address of a A SIP Redirect Server may help in resolving the current address of a
mobile target address. UAS.
5.2. The Location Function (LF) of a Receiving Provider 5.2. The Location Function (LF) of a Receiving Provider
5.2.1. Publish ENUM records 5.2.1. Publish ENUM records
The receiving peer SHOULD participate by publishing "E2U+sip" and The receiving peer SHOULD participate by publishing "E2U+sip" and
"E2U+pstn" records with sip: or sips: URIs wherever a public carrier "E2U+pstn" records with sip: or sips: URIs wherever a public carrier
ENUM root is available. This assumes that the receiving peer wants ENUM root is available. This assumes that the receiving peer wants
to peer by default. Even when the receiving peer does not want to to peer by default. When the receiving peer does not want to accept
accept traffic from specific initiating peers, it MAY still reject traffic from specific initiating peers, it MAY still reject requests
requests on a case-by-case basis. on a call-by-call basis.
5.2.2. Publish SIP DNS records 5.2.2. Publish SIP DNS records
To receive peer requests, the receiving peer MUST insure that it To receive peer requests, the receiving peer MUST insure that it
publishes appropriate NAPTR, SRV, and address (A and/or AAAA) records publishes appropriate NAPTR, SRV, and address (A and/or AAAA)
in the global DNS that resolve an appropriate transport, port, and records in the LF relevant to the peer's SF.
address to a relevant SIP server.
5.2.3. Subscribe Notify 5.2.3. Subscribe Notify
Policy function may also be optionally implemented by dynamic Policies function may also be optionally implemented by dynamic
subscribe, notify, and exchange of policy information and feature subscribe, notify, and exchange of policy information and feature
information among providers [22]. information among SSPs [22].
5.3. Signaling Function (SF) 5.3. Signaling Function (SF)
The purpose of signaling function is to perform routing of SIP The purpose of signaling function is to perform routing of SIP
messages, to optionally perform termination and re-initiation of a messages, to optionally perform termination and re-initiation of a
call, to optionally implement security and policies on SIP messages, call, to optionally implement security and policies on SIP messages,
and to assist in discovery/exchange of parameters to be used by the and to assist in discovery/exchange of parameters to be used by the
Media Function (MF). Media Function (MF).
The routing of SIP messages are performed by SIP proxies. The The signaling function perform the routing of SIP messages. The
optional termination and re-initiation of calls are performed by optional termination and re-initiation of calls are performed by the
B2BUA. signaling path border element (SBE).
Optionally, a SF may perform additional functions such as Session Optionally, a SF may perform additional functions such as Session
Admission Control, SIP Denial of Service protection, SIP Topology Admission Control, SIP Denial of Service protection, SIP Topology
Hiding, SIP header normalization, and SIP security, privacy and Hiding, SIP header normalization, and SIP security, privacy and
encryption. encryption.
The signaling function can also process SDP payloads for media The SF can also process SDP payloads for media information such as
information such as media type, bandwidth, and type of codec; then, media type, bandwidth, and type of codec; then, communicate this
communicate this information to the media function. Signaling information to the media function. Signaling function may optionally
function may optionally communicate with network layer to pass Layer communicate with the network to pass Layer 3 related policies [10]
3 related policies [10]
5.4. The Signaling Function (SF) of an Initiating Provider 5.4. The Signaling Function (SF) of an Initiating Provider
5.4.1. Setup TLS connection 5.4.1. Setup TLS connection
Once a transport, port, and address are found, the initiating peer Once a transport, port, and address are found, the initiating SSP
will open or find a reusable TLS connection to the peer. The will open or find a reusable TLS connection to the peer. The
initiating provider MUST verify the server certificate which SHOULD initiating provider MUST verify the server certificate that SHOULD
be rooted in a well-known certificate authority. The initiating be rooted in a well-known certificate authority. The initiating SSP
provider MUST be prepared to provide a TLS client certificate upon MUST be prepared to provide a TLS client certificate upon request
request during the TLS handshake. The client certificate MUST during the TLS handshake. The client certificate MUST contain a DNS
contain a DNS or URI choice type in the subjectAltName which or URI choice type in the subjectAltName which corresponds to the
corresponds to the domain asserted in the host production of the From domain asserted in the host production of the From header URI. The
header URI. The certificate SHOULD be valid and rooted in a well- certificate SHOULD be valid and rooted in a well-known certificate
known certificate authority. authority.
Note that the client certificate MAY contain a list of entries in the Note that the client certificate MAY contain a list of entries in
subjectAltName, only one of which has to match the domain in the From the subjectAltName, only one of which has to match the domain in the
header URI. From header URI.
5.4.2. IPSec 5.4.2. IPSec
In certain deployments the use of IPSec between the signaling In certain deployments the use of IPSec between the signaling
functions of the originating and terminating domains can be used as a functions of the originating and terminating domains can be used as
security mechanism instead of TLS. a security mechanism instead of TLS.
5.4.3. Co-Location 5.4.3. Co-Location
In this scenario the signaling functions are co-located in a In this scenario the SFs are co-located in a
physically secure location and/or are members of a segregated physically secure location and/or are members of a segregated
network. In this case messages between the originating and network. In this case messages between the originating and
terminating domains would be sent as clear text. terminating SSPs would be sent as clear text.
5.4.4. Send the SIP request 5.4.4. Send the SIP request
Once a TLS connection between the peers is established, the Once a TLS connection between the peers is established, the
initiating peer sends the request. When sending some requests, the initiating peer sends the request. When sending some requests, the
initiating peer MUST verify and assert the senders identity using the initiating peer MUST verify and assert the senders identity using
SIP Identity mechanism. the SIP Identity mechanism.
The domain name in the URI of the From: header MUST be a domain which The domain name in the URI of the From: header MUST be a domain
was present in the certificate presented when establishing the TLS which was present in the certificate provided when establishing the
connection for this request, even if the user part has an anonymous TLS connection for this request, even if the user part has an
value. If the From header contains the user URI parameter with the anonymous value. If the From header contains the user URI parameter
value of "phone", the user part of the From header URI MUST be a with the value of "phone", the user part of the From header URI MUST
complete and valid tel: URI [9] telephone-subscriber production, and be a complete and valid tel: URI [9] telephone-subscriber
SHOULD be a global-number. For example, the following are all production, and SHOULD be a global-number. For example, the
acceptable, the first three are encouraged: following are all acceptable and the first three are encouraged:
From: "John Doe" john.doe@example.net
From: "John Doe" <john.doe@example.net>
From: "+12125551212" <+12125551212@example.net;user=phone> From: "+12125551212" <+12125551212@example.net;user=phone>
From: "Anonymous" <anonymous@example.net> From: "Anonymous" <anonymous@example.net>
From: <4092;phone-context=+12125554000@example.net;user=phone> From: <4092;phone-context=+12125554000@example.net;user=phone>
From: "5551212" <5551212@example.net> From: "5551212" <5551212@example.net>
The following are not acceptable: The following are not acceptable:
From: "2125551212" <2125551212@example.net;user=phone> From: "2125551212" <2125551212@example.net;user=phone>
From: "Anonymous" <anonymous@anonymous.invalid> From: "Anonymous" <anonymous@anonymous.invalid>
In addition, for new dialog-forming requests and non-dialog-forming In addition, new requests MUST contain a valid Identity and
requests, the request MUST contain a valid Identity and Identity-Info Identity-Info header as described in [12]. The Identity-Info header
header as described in [12]. The Identity-Info header must present a must present a domain name that is represented in the certificate
domain name which is represented in the certificate presented when provided when establishing the TLS connection over which the request
establishing the TLS connection over which the request is sent. The is sent. The initiating peer SHOULD include an Identity header on
initiating peer SHOULD include an Identity header on in-dialog in-dialog requests as well, if the From header field value matches
requests as well, if the From header field value matches an identity an identity the initiating peer is willing to assert.
the initiating peer is willing to assert.
The initiating peer MAY include any SIP option-tags in Supported, The initiating peer MAY include any SIP option-tags in Supported,
Require, or Proxy-Require headers according to procedures in Require, or Proxy-Require headers according to procedures in
standards-track SIP extensions. Note however that the initiating standards-track SIP extensions. Note however that the initiating
peer MUST be prepared to fallback to baseline SIP functionality as peer MUST be prepared to fallback to baseline SIP functionality as
defined by the mandatory-to-implement features of RFC 3261, RFC 3263, defined by the mandatory-to-implement features of RFC 3261, RFC
and RFC 3264 [7], except that peers implementing this specification 3263,and RFC 3264 [7], except that peers implementing this
MUST implement SIP over TLS using the sip: URI scheme, the SIP specification MUST implement SIP over TLS using the sip: URI scheme,
Identity header, and RFC 4320 [10] non-INVITE transaction fixes. the SIP Identity header, and RFC 4320 [10] non-INVITE transaction
fixes.
5.5. The Signaling Function (SF) of an Initiating Provider 5.5. The Signaling Function (SF) of an Target Provider
5.5.1. Verify TLS connection 5.5.1. Verify TLS connection
When the receiving peer receives a TLS client hello, it responds with When the receiving peer receives a TLS client hello, it responds
its certificate. The receiving peer certificate SHOULD be valid and with its certificate. The receiving peer certificate SHOULD be
rooted in a well-known certificate authority. The receiving peer valid and rooted in a well-known certificate authority. The
MUST request and verify the client certificate during the TLS receiving peer MUST request and verify the client certificate during
handshake. the TLS handshake.
Once the initiating peer has been authenticated, the receiving peer Once the initiating peer has been authenticated, the receiving peer
can authorize communication from this peer based on the domain name can authorize communication from this peer based on the domain name
of the peer and the root of its certificate. This allows two of the peer and the root of its certificate. This allows two
authorization models to be used, together or separately. In the authorization models to be used, together or separately. In the
domain-based model, the receiving peer can allow communication from domain-based model, the receiving peer can allow communication from
peers with some trusted administrative domains which use general- peers with some trusted administrative domains that use general-
purpose certificate authorities, without explicitly permitting all purpose certificate authorities, without explicitly permitting all
domains with certificates rooted in the same authority. It also domains with certificates rooted in the same authority. It also
allows a certificate authority (CA) based model where every domain allows a certificate authority (CA) based model where every domain
with a valid certificate rooted in some list of CAs is automatically with a valid certificate rooted in some list of CAs is automatically
authorized. authorized.
5.5.2. Receive SIP requests 5.5.2. Receive SIP requests
Once a TLS connection is established, the receiving peer is prepared Once a TLS connection is established, the receiving peer is prepared
to receive incoming SIP requests. For new dialog-forming requests to receive incoming SIP requests. For new requests (dialog forming
and out-of-dialog requests, the receiving peer verifies that the or not) the receiving peer verifies that the target (request-URI) is
target (request-URI) is a domain which for which it is responsible. a domain that for which it is responsible. For these requests, there
(For these requests, there should be no remaining Route header field should be no remaining Route header field values. Next the receiving
values.) Next the receiving verifies that the Identity header is verifies that the Identity header is valid, corresponds to the
valid, corresponds to the message, corresponds to the Identity-Info message, and corresponds to the Identity-Info header, and that the
header, and that the domain in the From header corresponds to one of domain in the From header corresponds to one of the domains in the
the domains in the TLS client certificate. TLS client certificate.
For in-dialog requests, the receiving peer can verify that it For in-dialog requests, the receiving peer can verify that it
corresponds to the top-most Route header field value. The peer also corresponds to the top-most Route header field value. The peer also
validates any Identity header if present. validates any Identity header if present.
The receiving peer MAY reject incoming requests due to local policy. The receiving peer MAY reject incoming requests due to local policy.
When a request is rejected because the initiating peer is not When a request is rejected because the initiating peer is not
authorized to peer, the receiving peer SHOULD respond with a 403 authorized to peer, the receiving peer SHOULD respond with a 403
response with the reason phrase "Unsupported Peer". response with the reason phrase "Unsupported Peer".
5.6. Media Function (MF) 5.6. Media Function (MF)
Examples of the media function is to transform voice payload from one The purpose of the MF is to perform media related functions such as
coding (e.g., G.711) to another (e.g., EvRC), media relaying, media media transcoding and media security implementation between two
security, privacy, and encryption. SSPs.
Editor's Note: This section will be further updated. An Example of this is to transform a voice payload from one codec
(e.g., G.711) to another (e.g., EvRC). Additionally, the MF MAY
perform media relaying, media security, privacy, and encryption.
5.7. Policy Considerations 5.7. Policy Considerations
In the context of the SPEERMINT working group when two Layer 5 In the context of the SPEERMINT working group when two SSPs peer,
devices (e.g., SIP Proxies) peer, there is a need to exchange peering there MAY be a desire to exchange peering policy information
policy information. There are specifications in progress in the dynamically. There are specifications in progress in the SIPPING
SIPPING working group to define policy exchange between an UA and a working group to define policy exchange between an UA and a domain
domain [23] and providing profile data to SIP user agents [24] These [23] and providing profile data to SIP user agents [24] These
considerations borrow from both. considerations borrow from both.
Following the terminology introduced in [12], this package uses the Following the terminology introduced in [12], this package uses the
terms Peering Session-Independent and Session-Specific policies in terms Peering Session-Independent and Session-Specific policies in
the following context. the following context.
o Peering Session-Independent policies include Diffserv Marking, o Peering Session-Independent policies include Diffserv Marking,
Policing, Session Admission Control, domain reachabilities, Policing, Session Admission Control, and domain reachabilities,
amongst others. The time period between Peering Session- amongst others. The time period between Peering Session-
Independent policy changes is much greater than the time it takes Independent policy changes is much greater than the time it
to establish a call. takes to establish a call.
o Peering Session-Specific polices includes supported o Peering Session-Specific polices includes supported
connection/call rate, total number of connections/calls available, connection/call rate, total number of connections/calls
current utilization, amongst others. Peering Session-specific available, current utilization, amongst others. Peering
policies can change within the time it takes to establish a call. Session-specific policies can change within the time it takes
to establish a call.
These policies can be Peer dependent or independent, creating the These policies can be Peer dependent or independent, creating the
following peering policy tree definition: following peering policy tree definition:
Peer Independent o Peer Independent
Session dependent Session dependent
Session independent Session independent
Peer Dependent o Peer Dependent
Session dependent Session dependent
Session independent Session independent
6. Call Control and Media Control Deployment Options 6. Call Control and Media Control Deployment Options
The peering functions can either be deployed along the following two The peering functions can either be deployed along the following two
dimensions depending upon how the signaling function and the media dimensions depending upon how the signaling function and the media
function along with IP functions are implemented: function along with IP functions are implemented:
Composed or Decomposed: Addresses the question whether the media Composed or Decomposed: Addresses the question whether the media
paths must flow through the same physical and geographic nodes as the must flow through the same physical and geographic elements as SIP
call signaling, dialogs and sessions.
Centralized or Distributed: Addresses the question whether the Centralized or Distributed: Addresses the question whether the
logical and physical peering points are in one geographical location logical and physical peering points are in one geographical location
or distributed to multiple physical locations on the service provider or distributed to multiple physical locations on the SSP's network.
network.
In a composed model, SF and MF functions are implemented in one In a composed model, SF and MF functions are implemented in one
peering logical element. peering logical element.
Provider A Provider B Provider A Provider B
---------- . . ---------- ---------- . . ----------
/ \ . . / \ / \ . . / \
| | . _ . | | | | . _ . | |
| +----+ . / \_ . +----+ | | +----+ . / \_ . +----+ |
| | SF |<-----/ \------| SF | | | | SF |<-----/ \------| SF | |
skipping to change at page 17, line 26 skipping to change at page 16, line 46
| | . \__ _/ . | | | | . \__ _/ . | |
\_________ / . . \________ _/ \_________ / . . \________ _/
---------- ---------- ---------- ----------
--- Signal (SIP) --- Signal (SIP)
~~~ Bearer (RTP/IP) ~~~ Bearer (RTP/IP)
... Scope of peering ... Scope of peering
Figure 3: Decomposed v. Collapsed Peering Figure 3: Decomposed v. Collapsed Peering
The advantage of a collapsed peering architecture is that one-element The advantage of a collapsed peering architecture is that one-
solves all peering issues. Disadvantage examples of this architecture element solves all peering issues. Disadvantage examples of this
are single point failure, bottle neck, and complex scalability. architecture are single point of failure, bottleneck, and complex
scalability.
In a decomposed model, SF and MF are implemented in separate peering In a decomposed model, SF and MF are implemented in separate peering
logical elements. Signaling functions are implemented in a proxy and logical elements. SFs are implemented in a proxy and MFs are
media functions are implemented in another logical element. The implemented in another logical element. The scaling of signaling
scaling of signaling versus scaling of media may differ between versus scaling of media may differ between applications.
applications. Decomposing allows each to follow a separate migration Decomposing allows each to follow a separate migration path.
path.
This model allows the implementation of M:N model where one SF is This model allows the implementation of M:N model where one SF is
associated with multiple peering MF and one peering MF is associated associated with multiple peering MF and one peering MF is associated
with multiple peering proxies. Generally, a vertical protocol with multiple peering proxies. Generally, a vertical protocol
associates the relationship between a SF and a MF. This architecture associates the relationship between a SF and a MF. This architecture
reduces the potential of single point failure. This architecture, reduces the potential of a single point of failure. It allows
allows separation of the policy decision point and the policy separation of the policy decision point and the policy enforcement
enforcement point. An example of disadvantages is the scaling point. An example of disadvantages is the scaling complexity because
complexity because of the M:N relationship and latency due to the of the M:N relationship and latency due to the vertical control
vertical control messages between entities. messages between entities.
7. Address space considerations 7. Address space considerations
Peering must occur in a common address space, which is defined by the Peering must occur in a common address space, which is defined by
federation, which may be entirely on the public Internet, or some the federation, which may be entirely on the public Internet, or
private address space. The origination or termination networks may or some private address space. The origination or termination networks
may not entirely be in that same address space. If they are not, may or may not entirely be in that same address space. If they are
then a translation (NAT) may be needed before the signaling or media not, then a network address translation (NAT) or similar may be
is presented to the federation. The only requirement is that all needed before the signaling or media is presented correctly to the
entities across the peering interface are reachable. federation. The only requirement is that all associated entities
across the peering interface are reachable.
8. Security Considerations 8. Security Considerations
In all cases, cryptographic-based security should be maintained as an In all cases, cryptographic-based security should be maintained as
optional requirement between peering providers conditioned on the an optional requirement between peering providers conditioned on the
presence or absence of underlying physical security of peer presence or absence of underlying physical security of peer
connections, e.g. within the same secure physical building. connections, e.g. within the same secure physical building.
In order to maintain a consistent approach, unique and specialized In order to maintain a consistent approach, unique and specialized
security requirements common for the majority of peering security requirements common for the majority of peering
relationships, should be standardized within the IETF. These relationships, should be standardized within the IETF. These
standardized methods may enable capabilities such as dynamic peering standardized methods may enable capabilities such as dynamic peering
relationships across publicly maintained interconnections. relationships across publicly maintained interconnections.
TODO: Address RFC-3552 BCP items. TODO: Address RFC-3552 BCP items.
skipping to change at page 19, line 9 skipping to change at page 19, line 9
draft that helped to initiate work on this draft. draft that helped to initiate work on this draft.
A significant portion of this draft is taken from [14] with A significant portion of this draft is taken from [14] with
permission from the author R. Mahy. The other important contributor permission from the author R. Mahy. The other important contributor
is Otmar Lendl. is Otmar Lendl.
11. References 11. References
11.1. Normative References 11.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Bradner, S., "Key words for use in RFCs to Indicate
Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[2] Mealling, M. and R. Daniel, "The Naming Authority Pointer [2] Mealling, M. and R. Daniel, "The Naming Authority Pointer
(NAPTR) DNS Resource Record", RFC 2915, September 2000. (NAPTR) DNS Resource Record", RFC 2915, September 2000.
[3] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., [3] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP:
Session Initiation Protocol", RFC 3261, June 2002. Session Initiation Protocol", RFC 3261, June 2002.
[4] Rosenberg, J. and H. Schulzrinne, "Session Initiation Protocol [4] Rosenberg, J. and H. Schulzrinne, "Session Initiation Protocol
(SIP): Locating SIP Servers", RFC 3263, June 2002. (SIP): Locating SIP Servers", RFC 3263, June 2002.
[5] Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J., and [5] Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J., and
T. Wright, "Transport Layer Security (TLS) Extensions", RFC T. Wright, "Transport Layer Security (TLS) Extensions", RFC
4366, April 2006. 4366, April 2006.
[6] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, [6] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson,
"RTP: A Transport Protocol for Real-Time Applications", STD 64, "RTP: A Transport Protocol for Real-Time Applications", STD
RFC 3550, July 2003. 64, RFC 3550, July 2003.
[7] Peterson, J., Liu, H., Yu, J., and B. Campbell, "Using E.164 [7] Peterson, J., Liu, H., Yu, J., and B. Campbell, "Using E.164
numbers with the Session Initiation Protocol (SIP)", RFC 3824, numbers with the Session Initiation Protocol (SIP)", RFC 3824,
June 2004. June 2004.
[8] Peterson, J., "Address Resolution for Instant Messaging and [8] Peterson, J., "Address Resolution for Instant Messaging and
Presence",RFC 3861, August 2004. Presence",RFC 3861, August 2004.
[9] Peterson, J., "Telephone Number Mapping (ENUM) Service [9] Peterson, J., "Telephone Number Mapping (ENUM) Service
Registration for Presence Services", RFC 3953, January 2005. Registration for Presence Services", RFC 3953, January 2005.
skipping to change at page 20, line 7 skipping to change at page 20, line 7
[11] Peterson, J., "enumservice registration for Session Initiation [11] Peterson, J., "enumservice registration for Session Initiation
Protocol (SIP) Addresses-of-Record", RFC 3764, April 2004. Protocol (SIP) Addresses-of-Record", RFC 3764, April 2004.
[12] Livingood, J. and R. Shockey, "IANA Registration for an [12] Livingood, J. and R. Shockey, "IANA Registration for an
Enumservice Containing PSTN Signaling Information", RFC 4769, Enumservice Containing PSTN Signaling Information", RFC 4769,
November 2006. November 2006.
11.2. Informative References 11.2. Informative References
[13] Meyer, D., "SPEERMINT Terminology", draft-ietf-speermint- [13] Malas, D., "SPEERMINT Terminology", draft-ietf-speermint-
terminology-08 (work in progress), Junly 2007. terminology-16 (work in progress), February 2008.
[14] Mule, J-F., "SPEERMINT Requirements for SIP-based VoIP [14] Mule, J-F., "SPEERMINT Requirements for SIP-based VoIP
Interconnection", draft-ietf-speermint-requirements-02.txt, Interconnection", draft-ietf-speermint-requirements-03.txt,
July 2007. November 2007.
[15] Mahy, R., "A Minimalist Approach to Direct Peering", draft- [15] Mahy, R., "A Minimalist Approach to Direct Peering", draft-
mahy-speermint-direct-peering-02.txt, July 2007. mahy-speermint-direct-peering-02.txt, July 2007.
[16] Penno, R., et al., "SPEERMINT Routing Architecture Message [16] Penno, R., et al., "SPEERMINT Routing Architecture Message
Flows", draft-ietf-speermint-flows-02.txt", April 2007. Flows", draft-ietf-speermint-flows-02.txt", April 2007.
[17] Lee, Y., "Session Peering Use Case for Cable", draft-lee- [17] Houri, A., et al., "RTC Provisioning Requirements", draft-
speermint-use-case-cable-01.txt, June, 2006.
[18] Houri, A., et al., "RTC Provisioning Requirements", draft-
houri-speermint-rtc-provisioning-reqs-00.txt, June, 2006. houri-speermint-rtc-provisioning-reqs-00.txt, June, 2006.
[19] Habler, M., et al., "A Federation based VOIP Peering [18] Habler, M., et al., "A Federation based VOIP Peering
Architecture", draft-lendl-speermint-federations-03.txt, Architecture", draft-lendl-speermint-federations-03.txt,
September 2006. September 2006.
[20] Mahy, R., "A Telephone Number Mapping (ENUM) Service [19] Mahy, R., "A Telephone Number Mapping (ENUM) Service
Registration for Instant Messaging (IM) Services", draft-ietf- Registration for Instant Messaging (IM) Services", RFC 5028
enum-im-service-03 (work in progress), March 2006.
[21] Haberler, M. and R. Stastny, "Combined User and Carrier ENUM in [20] Haberler, M. and R. Stastny, "Combined User and Carrier ENUM
the e164.arpa tree", draft-haberler-carrier-enum-03 (work in in the e164.arpa tree", draft-haberler-carrier-enum-03 (work
progress), March 2006. in progress), March 2006.
[22] Penno, R., Malas D., and Melampy, P., "A Session Initiation [21] Penno, R., Malas D., and Melampy, P., "A Session Initiation
Protocol (SIP) Event package for Peering", draft-penno-sipping- Protocol (SIP) Event package for Peering", draft-penno-
peering-package-00 (work in progress), September 2006. sipping-peering-package-01 (work in progress), September 2006.
[23] Hollander, D., Bray, T., and A. Layman, "Namespaces in XML", [22] Hollander, D., Bray, T., and A. Layman, "Namespaces in XML",
W3C REC REC-xml-names-19990114, January 1999. W3C REC REC-xml-names-19990114, January 1999.
[24] Burger, E (Ed.), "A Mechanism for Content Indirection in [23] Burger, E (Ed.), "A Mechanism for Content Indirection in
Session Initiation Protocol (SIP) Messages", RFC 4483, May
2006
Author's Addresses Author's Addresses
Mike Hammer Mike Hammer
Cisco Systems Cisco Systems
13615 Dulles Technology Drive 13615 Dulles Technology Drive
Herndon, VA 20171 Herndon, VA 20171
USA USA
Email: mhammer@cisco.com Email: mhammer@cisco.com
skipping to change at page 21, line 43 skipping to change at page 21, line 43
Adam Uzelac Adam Uzelac
Global Crossing Global Crossing
1120 Pittsford Victor Road 1120 Pittsford Victor Road
PITTSFORD, NY 14534 PITTSFORD, NY 14534
USA USA
Email: adam.uzelac@globalcrossing.com Email: adam.uzelac@globalcrossing.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
pertain to the implementation or use of the technology described in to pertain to the implementation or use of the technology described
this document or the extent to which any license under such rights in this document or the extent to which any license under such
might or might not be available; nor does it represent that it has rights might or might not be available; nor does it represent that
made any independent effort to identify any such rights. Information it has made any independent effort to identify any such rights.
on the procedures with respect to rights in RFC documents can be Information on the procedures with respect to rights in RFC
found in BCP 78 and BCP 79. documents can be found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of attempt made to obtain a general license or permission for the use
such proprietary rights by implementers or users of this of such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository
http://www.ietf.org/ipr. at http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at this standard. Please address the information to the IETF at
ietf-ipr@ietf.org. ietf-ipr@ietf.org.
Disclaimer of Validity Disclaimer of Validity
This document and the information contained herein are provided on an This document and the information contained herein are provided on
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
FOR A PARTICULAR PURPOSE.
Copyright Statement Copyright Statement
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
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. 113 change blocks. 
302 lines changed or deleted 309 lines changed or added

This html diff was produced by rfcdiff 1.34. The latest version is available from http://tools.ietf.org/tools/rfcdiff/