draft-ietf-speermint-architecture-19.txt		rfc6406.txt
	SPEERMINT D. Malas, Ed.		Internet Engineering Task Force (IETF) D. Malas, Ed.
	Internet-Draft CableLabs		Request for Comments: 6406 CableLabs
	Intended status: Informational J. Livingood, Ed.		Category: Informational J. Livingood, Ed.
	Expires: August 22, 2011 Comcast		ISSN: 2070-1721 Comcast
	February 18, 2011		November 2011
	Session PEERing for Multimedia INTerconnect Architecture		Session PEERing for Multimedia INTerconnect (SPEERMINT) Architecture
	draft-ietf-speermint-architecture-19
	Abstract		Abstract
	This document defines a peering architecture for the Session		This document defines a peering architecture for the Session
	Initiation Protocol (SIP), its functional components and interfaces.		Initiation Protocol (SIP) and its functional components and
	It also describes the components and the steps necessary to establish		interfaces. It also describes the components and the steps necessary
	a session between two SIP Service Provider (SSP) peering domains.		to establish a session between two SIP Service Provider (SSP) peering
			domains.
	Status of this Memo
	This Internet-Draft is submitted in full conformance with the		Status of This Memo
	provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		This document is not an Internet Standards Track specification; it is
	Task Force (IETF). Note that other groups may also distribute		published for informational purposes.
	working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		This document is a product of the Internet Engineering Task Force
	and may be updated, replaced, or obsoleted by other documents at any		(IETF). It represents the consensus of the IETF community. It has
	time. It is inappropriate to use Internet-Drafts as reference		received public review and has been approved for publication by the
	material or to cite them other than as "work in progress."		Internet Engineering Steering Group (IESG). Not all documents
			approved by the IESG are a candidate for any level of Internet
			Standard; see Section 2 of RFC 5741.
	This Internet-Draft will expire on August 22, 2011.		Information about the current status of this document, any errata,
			and how to provide feedback on it may be obtained at
			http://www.rfc-editor.org/info/rfc6406.
	Copyright Notice		Copyright Notice
	Copyright (c) 2011 IETF Trust and the persons identified as the		Copyright (c) 2011 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 3, line 7		skipping to change at page 2, line 19
	modifications of such material outside the IETF Standards Process.		modifications of such material outside the IETF Standards Process.
	Without obtaining an adequate license from the person(s) controlling		Without obtaining an adequate license from the person(s) controlling
	the copyright in such materials, this document may not be modified		the copyright in such materials, this document may not be modified
	outside the IETF Standards Process, and derivative works of it may		outside the IETF Standards Process, and derivative works of it may
	not be created outside the IETF Standards Process, except to format		not be created outside the IETF Standards Process, except to format
	it for publication as an RFC or to translate it into languages other		it for publication as an RFC or to translate it into languages other
	than English.		than English.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4		1. Introduction ....................................................3
	2. New Terminology . . . . . . . . . . . . . . . . . . . . . . . 4		2. New Terminology .................................................3
	2.1. Session Border Controller (SBC) . . . . . . . . . . . . . 4		2.1. Session Border Controller (SBC) ............................3
	2.2. Carrier-of-Record . . . . . . . . . . . . . . . . . . . . 5		2.2. Carrier-of-Record ..........................................4
	3. Reference Architecture . . . . . . . . . . . . . . . . . . . . 5		3. Reference Architecture ..........................................4
	4. Procedures of Inter-Domain SSP Session Establishment . . . . . 7		4. Procedures of Inter-Domain SSP Session Establishment ............6
	5. Relationships Between Functions/Elements . . . . . . . . . . . 8		5. Relationships between Functions/Elements ........................7
	6. Recommended SSP Procedures . . . . . . . . . . . . . . . . . . 8		6. Recommended SSP Procedures ......................................7
	6.1. Originating or Indirect SSP Procedures . . . . . . . . . . 8		6.1. Originating or Indirect SSP Procedures .....................7
	6.1.1. The Look-Up Function (LUF) . . . . . . . . . . . . . . 9		6.1.1. The Lookup Function (LUF) ...........................8
	6.1.1.1. Target Address Analysis . . . . . . . . . . . . . 9		6.1.1.1. Target Address Analysis ....................8
	6.1.1.2. ENUM Lookup . . . . . . . . . . . . . . . . . . . 9		6.1.1.2. ENUM Lookup ................................8
	6.1.2. Location Routing Function (LRF) . . . . . . . . . . . 10		6.1.2. Location Routing Function (LRF) .....................9
	6.1.2.1. DNS Resolution . . . . . . . . . . . . . . . . . . 10		6.1.2.1. DNS Resolution .............................9
	6.1.2.2. Routing Table . . . . . . . . . . . . . . . . . . 10		6.1.2.2. Routing Table ..............................9
	6.1.2.3. LRF to LRF Routing . . . . . . . . . . . . . . . . 11		6.1.2.3. LRF to LRF Routing ........................10
	6.1.3. The Signaling Path Border Element (SBE) . . . . . . . 11		6.1.3. The Signaling Path Border Element (SBE) ............10
	6.1.3.1. Establishing a Trusted Relationship . . . . . . . 11		6.1.3.1. Establishing a Trusted Relationship .......10
	6.1.3.2. IPSec . . . . . . . . . . . . . . . . . . . . . . 11		6.1.3.2. IPsec .....................................10
	6.1.3.3. Co-Location . . . . . . . . . . . . . . . . . . . 11		6.1.3.3. Co-Location ...............................11
	6.1.3.4. Sending the SIP Request . . . . . . . . . . . . . 12		6.1.3.4. Sending the SIP Request ...................11
	6.2. Target SSP Procedures . . . . . . . . . . . . . . . . . . 12		6.2. Target SSP Procedures .....................................11
	6.2.1. TLS . . . . . . . . . . . . . . . . . . . . . . . . . 12		6.2.1. TLS ................................................11
	6.2.2. Receive SIP Requests . . . . . . . . . . . . . . . . . 12		6.2.2. Receive SIP Requests ...............................11
	6.3. Data Path Border Element (DBE) . . . . . . . . . . . . . . 13		6.3. Data Path Border Element (DBE) ............................12
	7. Address Space Considerations . . . . . . . . . . . . . . . . . 13		7. Address Space Considerations ...................................12
	8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13		8. Acknowledgments ................................................12
	9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13		9. Security Considerations ........................................12
	10. Security Considerations . . . . . . . . . . . . . . . . . . . 13		10. Contributors ..................................................13
	11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 14		11. References ....................................................14
	12. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 15		11.1. Normative References .....................................14
	13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16		11.2. Informative References ...................................15
	13.1. Normative References . . . . . . . . . . . . . . . . . . . 16
	13.2. Informative References . . . . . . . . . . . . . . . . . . 18
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
	1. Introduction		1. Introduction
	This document defines a reference peering architecture for the		This document defines a reference peering architecture for the
	Session Initiation Protocol (SIP)[RFC3261], it's functional		Session Initiation Protocol (SIP) [RFC3261], it's functional
	components and interfaces, in the context of session peering for		components and interfaces in the context of session peering for
	multimedia interconnects. In this process, we define the peering		multimedia interconnects. In this process, we define the peering
	reference architecture, its functional components, and peering		reference architecture and its functional components, and peering
	interface functions from the perspective of a SIP Service Provider's		interface functions from the perspective of a SIP Service Provider's
	(SSP) [RFC5486] network. Thus, it also describes the components and		(SSP's) [RFC5486] network. Thus, it also describes the components
	the steps necessary to establish a session between two SSP peering		and the steps necessary to establish a session between two SSP
	domains.		peering domains.
	An SSP may also be referred to as an Internet Telephony Service		An SSP may also be referred to as an Internet Telephony Service
	Provider (ITSP). While the terms ITSP and SSP are frequently used		Provider (ITSP). While the terms ITSP and SSP are frequently used
	interchangeably, this document and other subsequent SIP peering-		interchangeably, this document and other subsequent SIP peering-
	related documents should use the term SSP. SSP more accurately		related documents should use the term SSP. SSP more accurately
	depicts the use of SIP as the underlying layer 5 signaling protocol.		depicts the use of SIP as the underlying Layer 5 signaling protocol.
	This architecture enables the interconnection of two SSPs in layer 5		This architecture enables the interconnection of two SSPs in Layer 5
	peering, as defined in the SIP-based session peering requirements		peering, as defined in the SIP-based session peering requirements
	[I-D.ietf-speermint-requirements].		[RFC6271].
	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 Session Peering for		This document uses terminology defined in "Session Peering for
	Multimedia Interconnect (SPEERMINT) Terminology document [RFC5486].		Multimedia Interconnect (SPEERMINT) Terminology" [RFC5486]. In
	Apart from normative references included herein, readers may also		addition to normative references included herein, readers may also
	find [I-D.ietf-speermint-voip-consolidated-usecases] informative.		find [RFC6405] informative.
	2. New Terminology		2. New Terminology
	[RFC5486] is a key reference for the majority of the SPEERMINT-		[RFC5486] is a key reference for the majority of the SPEERMINT-
	related terminology used in this document. However, some additional		related terminology used in this document. However, some additional
	new terms are used here as follows in this section.		new terms are used here as follows in this section.
	2.1. Session Border Controller (SBC)		2.1. Session Border Controller (SBC)
	A Session Border Controller (SBC) is referred to in Section 5. An		A Session Border Controller (SBC) is referred to in Section 5. An
	SBC can contain a Signaling Function (SF), Signaling Path Border		SBC can contain a Signaling Function (SF), Signaling Path Border
	Element (SBE) and Data Path Border Element (DBE), and may perform the		Element (SBE) and Data Path Border Element (DBE), and may perform the
	Look-Up Function (LUF) and Location Routing Function (LRF) functions,		Lookup Function (LUF) and Location Routing Function (LRF), as
	as described in Section 3. Whether the SBC performs one or more of		described in Section 3. Whether the SBC performs one or more of
	these functions is generally speaking dependent upon how a SIP		these functions is, generally speaking, dependent upon how a SIP
	Service Provider (SSP) configures such a network element. In		Service Provider (SSP) configures such a network element. In
	addition, requirements for an SBC can be found in [RFC5853].		addition, requirements for an SBC can be found in [RFC5853].
	2.2. Carrier-of-Record		2.2. Carrier-of-Record
	A carrier-of-record, as used in Section 6.1.2.2, is defined in		A carrier-of-record, as used in Section 6.1.2.2, is defined in
	[RFC5067]. That document describes the term to refer to the entity		[RFC5067]. That document describes the term as referring to the
	having discretion over the domain and zone content and acting as the		entity having discretion over the domain and zone content and acting
	registrant for a telephone number, as represented in ENUM. This can		as the registrant for a telephone number, as represented in ENUM.
	be:		This can be as follows:
	o the Service Provider to which the E.164 number was allocated for		o the service provider to which the E.164 number was allocated for
	end user assignment, whether by the National Regulatory Authority		end user assignment, whether by the National Regulatory Authority
	(NRA) or the International Telecommunication Union (ITU), for		(NRA) or the International Telecommunication Union (ITU), for
	instance, a code under "International Networks" (+882) or		instance, a code under "International Networks" (+882) or
	"Universal Personal Telecommunications (UPT)" (+878) or,		"Universal Personal Telecommunications (UPT)" (+878), or
	o if the number is ported, the service provider to which the number		o if the number is ported, the service provider to which the number
	was ported, or		was ported, or
	o where numbers are assigned directly to end users, the service		o where numbers are assigned directly to end users, the service
	provider that the end user number assignee has chosen to provide a		provider that the end user number assignee has chosen to provide a
	Public Switched Telephone Network/Public Land Mobile Network		Public Switched Telephone Network / Public Land Mobile Network
	(PSTN/ PLMN) point-of-interconnect for the number.		(PSTN/PLMN) point-of-interconnect for the number.
	It is understood that the definition of carrier-of-record within a		It is understood that the definition of "carrier-of-record" within a
	given jurisdiction is subject to modification by national		given jurisdiction is subject to modification by national
	authorities.		authorities.
	3. Reference Architecture		3. Reference Architecture
	The following figure depicts the architecture and logical functions		The following figure depicts the architecture and logical functions
	that form peering between two SSPs.		that form peering between two SSPs.
	For further details on the elements and functions described in this		For further details on the elements and functions described in this
	figure, please refer to [RFC5486]. The following terms, which appear		figure, please refer to [RFC5486]. The following terms, which appear
	in Figure 1, which are documented in [RFC5486] are reproduced here		in Figure 1 and are documented in [RFC5486], are reproduced here for
	for simplicity.		simplicity.
	- Data Path Border Element (DBE): A data path border element (DBE) is		o Data Path Border Element (DBE): A data path border element (DBE)
	located on the administrative border of a domain through which flows		is located on the administrative border of a domain through which
	the media associated with an inter-domain session. It typically		the media associated with an inter-domain session flows.
	provides media-related functions such as deep packet inspection and		Typically, it provides media-related functions such as deep packet
	modification, media relay, and firewall-traversal support. The DBE		inspection and modification, media relay, and firewall-traversal
	may be controlled by the SBE.		support. The DBE may be controlled by the SBE.
	- E.164 Number Mapping (ENUM): See [RFC3761].		o E.164 Number Mapping (ENUM): See [RFC6116].
	- Fully Qualified Domain Name (FQDN): See Section 5.1 of [RFC1035].		o Fully Qualified Domain Name (FQDN): See [RFC1035].
	- Location Routing Function (LRF): The Location Routing Function		o Location Routing Function (LRF): The Location Routing Function
	(LRF) determines for the target domain of a given request the		(LRF) determines, for the target domain of a given request, the
	location of the SF in that domain, and optionally develops other SED		location of the SF in that domain, and optionally develops other
	required to route the request to that domain. An example of the LRF		Session Establishment Data (SED) required to route the request to
	may be applied to either example in Section 4.3.3 of [RFC5486]. Once		that domain. An example of the LRF may be applied to either
	the ENUM response or SIP 302 redirect is received with the		example in Section 4.3.3 of [RFC5486]. Once the ENUM response or
	destination's SIP URI, the LRF must derive the destination peer's SF		SIP 302 redirect is received with the destination's SIP URI, the
	from the FQDN in the domain portion of the URI. In some cases, some		LRF must derive the destination peer's SF from the FQDN in the
	entity (usually a 3rd party or federation) provides peering		domain portion of the URI. In some cases, some entity (usually a
	assistance to the originating SSP by providing this function. The		third party or federation) provides peering assistance to the
	assisting entity may provide information relating to direct (Section		Originating SSP by providing this function. The assisting entity
	4.2.1 of [RFC5486]) or indirect (Section 4.2.2 of [RFC5486]) peering		may provide information relating to direct (Section 4.2.1 of
	as necessary.		[RFC5486]) or indirect (Section 4.2.2 of [RFC5486]) peering as
			necessary.
	- Look-Up Function (LUF): The Look-Up Function (LUF) determines for a		o Lookup Function (LUF): The Lookup Function (LUF) determines, for a
	given request the target domain to which the request should be		given request, the target domain to which the request should be
	routed. An example of an LUF is an ENUM [4] look-up or a SIP INVITE		routed. An example of an LUF is an ENUM [4] look-up or a SIP
	request to a SIP proxy providing redirect responses for peers. In		INVITE request to a SIP proxy providing redirect responses for
	some cases, some entity (usually a 3rd party or federation) provides		peers. In some cases, some entity (usually a third party or
	peering assistance to the originating SSP by providing this function.		federation) provides peering assistance to the Originating SSP by
	The assisting entity may provide information relating to direct		providing this function. The assisting entity may provide
	(Section 4.2.1 of [RFC5486]) or indirect (Section 4.2.2 of [RFC5486])		information relating to direct (Section 4.2.1 of [RFC5486]) or
	peering as necessary.		indirect (Section 4.2.2 of [RFC5486]) peering as necessary.
	- Real-Time Transport Protocol (RTP): See [RFC3550].		o Real-time Transport Protocol (RTP): See [RFC3550].
	- Session Initiation Protocol (SIP): See [RFC3261].		o Session Initiation Protocol (SIP): See [RFC3261].
	- Signaling Path Border Element (SBE): A signaling path border		o Signaling Path Border Element (SBE): A signaling path border
	element (SBE) is located on the administrative border of a domain		element (SBE) is located on the administrative border of a domain
	through which inter-domain session layer messages will flow. It		through which inter-domain session-layer messages will flow.
	typically provides signaling functions such as protocol inter-working		Typically, it provides Signaling Functions such as protocol inter-
	(for example, H.323 to SIP), identity and topology hiding, and		working (for example, H.323 to SIP), identity and topology hiding,
	Session Admission Control for a domain.		and Session Admission Control for a domain.
	- Signaling Function (SF): The Signaling Function (SF) performs		o Signaling Function (SF): The Signaling Function (SF) performs
	routing of SIP requests for establishing and maintaining calls, and		routing of SIP requests for establishing and maintaining calls and
	to assist in the discovery or exchange of parameters to be used by		in order to assist in the discovery or exchange of parameters to
	the Media Function (MF). The SF is a capability of SIP processing		be used by the Media Function (MF). The SF is a capability of SIP
	elements such as SIP proxies, SBEs, and user agents.		processing elements such as SIP proxies, SBEs, and User Agents.
	- SIP Service Provider (SSP): A SIP Service Provider (SSP) is an		o SIP Service Provider (SSP): A SIP Service Provider (SSP) is an
	entity that provides session services utilizing SIP signaling to its		entity that provides session services utilizing SIP signaling to
	customers. In the event that the SSP is also a function of the SP,		its customers. In the event that the SSP is also a function of
	it may also provide media streams to its customers. Such an SSP may		the SP, it may also provide media streams to its customers. Such
	additionally be peered with other SSPs. An SSP may also interconnect		an SSP may additionally be peered with other SSPs. An SSP may
	with the PSTN.		also interconnect with the PSTN.
	+=============++ ++=============+		+=============++ ++=============+
	|| ||		|| ||
	+-----------+ +-----------+		+-----------+ +-----------+
	| SBE | +-----+ | SBE |		| SBE | +-----+ | SBE |
	| +-----+ | SIP |Proxy| | +-----+ |		| +-----+ | SIP |Proxy| | +-----+ |
	| | LUF |<-|------>|ENUM | | | LUF | |		| | LUF |<-|------>|ENUM | | | LUF | |
	| +-----+ | ENUM |TN DB| | +-----+ |		| +-----+ | ENUM |TN DB| | +-----+ |
	SIP | | +-----+ | |		SIP | | +-----+ | |
	------>| +-----+ | DNS +-----+ | +-----+ |		------>| +-----+ | DNS +-----+ | +-----+ |
	skipping to change at page 7, line 36		skipping to change at page 6, line 36
	SSP1 Network || || SSP2 Network		SSP1 Network || || SSP2 Network
	+=============++ ++=============+		+=============++ ++=============+
	Reference Architecture		Reference Architecture
	Figure 1		Figure 1
	4. Procedures of Inter-Domain SSP Session Establishment		4. Procedures of Inter-Domain SSP Session Establishment
	This document assumes that in order for a session to be established		This document assumes that in order for a session to be established
	from a User Agent (UA) in the originating (or indirect) SSP's network		from a User Agent (UA) in the Originating (or Indirect) SSP's network
	to an UA in the Target SSP's network the following steps are taken:		to a UA in the Target SSP's network the following steps are taken:
	1. Determine the target or indirect SSP via the LUF. (Note: If the		1. Determine the Target or Indirect SSP via the LUF. (Note: If the
	target address represents an intra-SSP resource, the behavior is		target address represents an intra-SSP resource, the behavior is
	out-of-scope with respect to this draft.)		out of scope with respect to this document.)
	2. Determine the address of the SF of the target SSP via the LRF.		2. Determine the address of the SF of the Target SSP via the LRF.
	3. Establish the session		3. Establish the session.
	4. Exchange the media, which could include voice, video, text, etc.		4. Exchange the media, which could include voice, video, text, etc.
	5. End the session (BYE)		5. End the session (BYE)
	The originating or indirect SSP would perform steps 1-4, the target		The Originating or Indirect SSP would perform steps 1-4, the Target
	SSP would perform steps 4, and either one can perform step 5.		SSP would perform step 4, and either one can perform step 5.
	In the case the target SSP changes, then steps 1-4 would be repeated.		In the case that the Target SSP changes, steps 1-4 would be repeated.
	This is reflected in Figure 1 that shows the target SSP with its own		This is reflected in Figure 1, which shows the Target SSP with its
	peering functions.		own peering functions.
	5. Relationships Between Functions/Elements		5. Relationships between Functions/Elements
	Please also refer to Figure 1.		Please also refer to Figure 1.
	o An SBE can contain a Signaling Function (SF).		o An SBE can contain a Signaling Function (SF).
	o An SF can perform a Look-Up Function (LUF) and Location Routing		o An SF can perform a Lookup Function (LUF) and Location Routing
	Function (LRF).		Function (LRF).
	o As an additional consideration, a Session Border Controller, can		o As an additional consideration, a Session Border Controller, can
	contain an SF, SBE and DBE, and may act as both an LUF and LRF.		contain an SF, SBE and DBE, and may act as both an LUF and LRF.
	o The following functions may communicate as follows in an example		o The following functions may communicate as follows in an example
	SSP network, depending upon various real-world implementations:		SSP network, depending upon various real-world implementations:
	* SF may communicate with LUF, LRF, SBE and SF		* SF may communicate with the LUF, LRF, SBE, and SF
	* LUF may communicate with SF and SBE		* LUF may communicate with the SF and SBE
	* LRF may communicate with SF and SBE		* LRF may communicate with the SF and SBE
	6. Recommended SSP Procedures		6. Recommended SSP Procedures
	This section describes the functions in more detail and provides some		This section describes the functions in more detail and provides some
	recommendations on the role they would play in a SIP call in a Layer		recommendations on the role they would play in a SIP call in a Layer
	5 peering scenario.		5 peering scenario.
	Some of the information in the section is taken from		Some of the information in this section is taken from [RFC6271] and
	[I-D.ietf-speermint-requirements] and is included here for continuity		is included here for continuity purposes. It is also important to
	purposes. It is also important to refer to Section 3.2 of		refer to Section 3.2 of [RFC6404], particularly with respect to the
	[I-D.ietf-speermint-voipthreats], particularly with respect to the		use of IPsec and TLS.
	use of IPSec and TLS.
	6.1. Originating or Indirect SSP Procedures		6.1. Originating or Indirect SSP Procedures
	This section describes the procedures of the originating or indirect		This section describes the procedures of the Originating or indirect
	SSP.		SSP.
	6.1.1. The Look-Up Function (LUF)		6.1.1. The Lookup Function (LUF)
	The purpose of the LUF is to determine the SF of the target domain of		The purpose of the LUF is to determine the SF of the target domain of
	a given request and optionally to develop Session Establishment Data.		a given request and optionally to develop Session Establishment Data.
	It is important to note that the LUF may utilize the public e164.arpa		It is important to note that the LUF may utilize the public e164.arpa
	ENUM root, as well as one or more private roots. When private roots		ENUM root, as well as one or more private roots. When private roots
	are used specialized routing rules may be implemented, and these		are used, specialized routing rules may be implemented; these rules
	rules may vary depending upon whether an originating or indirect SSP		may vary depending upon whether an Originating or Indirect SSP is
	is querying the LUF.		querying the LUF.
	6.1.1.1. Target Address Analysis		6.1.1.1. Target Address Analysis
	When the originating (or indirect) SSP receives a request to		When the Originating (or Indirect) SSP receives a request to
	communicate, it analyzes the target URI to determine whether the call		communicate, it analyzes the target URI to determine whether the call
	needs to be routed internal or external to its network. The analysis		needs to be routed internally or externally to its network. The
	method is internal to the SSP; thus, outside the scope of SPEERMINT.		analysis method is internal to the SSP; thus, outside the scope of
			SPEERMINT.
	If the target address does not represent a resource inside the		If the target address does not represent a resource inside the
	originating (or indirect) SSP's administrative domain or federation		Originating (or Indirect) SSP's administrative domain or federation
	of domains, then the originating (or indirect) SSP performs a Lookup		of domains, then the Originating (or Indirect) SSP performs a Lookup
	Function (LUF) to determine a target address, and then it resolves		Function (LUF) to determine a target address, and then it resolves
	the call routing data by using the Location routing Function (LRF).		the call routing data by using the Location Routing Function (LRF).
	For example, if the request to communicate is for an im: or pres: URI		For example, if the request to communicate is for an im: or pres: URI
	type [RFC3861] [RFC3953], the originating (or indirect) SSP follows		type [RFC3861] [RFC3953], the Originating (or Indirect) SSP follows
	the procedures in [RFC3861]. If the highest priority supported URI		the procedures in [RFC3861]. If the highest priority supported URI
	scheme is sip: or sips: the originating (or indirect) SSP skips to		scheme is sip: or sips:, the Originating (or Indirect) SSP skips to
	SIP DNS resolution in Section 5.1.3. Likewise, if the target address		SIP DNS resolution in Section 5.1.3. Likewise, if the target address
	is already a sip: or sips: URI in an external domain, the originating		is already a sip: or sips: URI in an external domain, the Originating
	(or indirect) SSP skips to SIP DNS resolution in Section 6.1.2.1.		(or Indirect) SSP skips to SIP DNS resolution in Section 6.1.2.1.
	This may be the case, to use one example, with		This may be the case, to use one example, with
	"sips:bob@biloxi.example.com".		"sips:bob@biloxi.example.com".
	If the target address corresponds to a specific E.164 address, the		If the target address corresponds to a specific E.164 address, the
	SSP may need to perform some form of number plan mapping according to		SSP may need to perform some form of number plan mapping according to
	local policy. For example, in the United States, a dial string		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"; in the United
	Kingdom "00 1" could be converted to "+1". Once the SSP has an E.164		Kingdom, "00 1" could be converted to "+1". Once the SSP has an
	address, it can use ENUM.		E.164 address, it can use ENUM.
	6.1.1.2. ENUM Lookup		6.1.1.2. ENUM Lookup
	If an external E.164 address is the target, the originating (or		If an external E.164 address is the target, the Originating (or
	indirect) SSP consults the public "User ENUM" rooted at e164.arpa,		Indirect) SSP consults the public "User ENUM" rooted at e164.arpa,
	according to the procedures described in [RFC3761]. The SSP must		according to the procedures described in [RFC6116]. The SSP must
	query for the "E2U+sip" enumservice as described in [RFC3764], but		query for the "E2U+sip" enumservice as described in [RFC3764], but
	may check for other enumservices. The originating (or indirect) SSP		may check for other enumservices. The Originating (or Indirect) SSP
	may consult a cache or alternate representation of the ENUM data		may consult a cache or alternate representation of the ENUM data
	rather than actual DNS queries. Also, the SSP may skip actual DNS		rather than actual DNS queries. Also, the SSP may skip actual DNS
	queries if the originating (or indirect) SSP is sure that the target		queries if the Originating (or Indirect) SSP is sure that the target
	address country code is not represented in e164.arpa.		address country code is not represented in e164.arpa.
	If an im: or pres: URI is chosen based on an "E2U+im" [RFC3861] or		If an im: or pres: URI is chosen based on an "E2U+im" [RFC3861] or
	"E2U+pres" [RFC3953] enumserver, the SSP follows the procedures for		"E2U+pres" [RFC3953] enumserver, the SSP follows the procedures for
	resolving these URIs to URIs for specific protocols such as SIP or		resolving these URIs to URIs for specific protocols such as SIP or
	XMPP as described in the previous section.		Extensible Messaging and Presence Protocol (XMPP) as described in the
			previous section.
	The NAPTR response to the ENUM lookup may be a SIP AoR (such as		The Naming Authority Pointer (NAPTR) response to the ENUM lookup may
	"sips:bob@example.com") or SIP URI (such as		be a SIP address of record (AOR) (such as "sips:bob@example.com") or
	"sips:bob@sbe1.biloxi.example.com"). In the case of when a SIP URI		SIP URI (such as "sips:bob@sbe1.biloxi.example.com"). In the case
	is returned, the originating (or indirect) SSP has sufficient routing		when a SIP URI is returned, the Originating (or Indirect) SSP has
	information to locate the target SSP. In the case of when a SIP AoR		sufficient routing information to locate the Target SSP. In the case
	is returned, the SF then uses the LRF to determine the URI for more		of when a SIP AoR is returned, the SF then uses the LRF to determine
	explicitly locating the target SSP.		the URI for more explicitly locating the Target SSP.
	6.1.2. Location Routing Function (LRF)		6.1.2. Location Routing Function (LRF)
	The LRF of an originating (or indirect) SSP analyzes target address		The LRF of an Originating (or Indirect) SSP analyzes target address
	and target domain identified by the LUF, and discovers the next hop		and target domain identified by the LUF, and discovers the next-hop
	signaling function (SF) in a peering relationship. The resource to		Signaling Function (SF) in a peering relationship. The resource to
	determine the SF of the target domain might be provided by a third-		determine the SF of the target domain might be provided by a third
	party as in the assisted-peering case. The following sections define		party as in the assisted-peering case. The following sections define
	mechanisms which may be used by the LRF. These are not in any		mechanisms that may be used by the LRF. These are not in any
	particular order and, importantly, not all of them have to be used.		particular order and, importantly, not all of them have to be used.
	6.1.2.1. DNS Resolution		6.1.2.1. DNS Resolution
	The originating (or indirect) SSP uses the procedures in Section 4 of		The Originating (or Indirect) SSP uses the procedures in Section 4 of
	[RFC3263] to determine how to contact the receiving SSP. To		[RFC3263] to determine how to contact the receiving SSP. To
	summarize the [RFC3263] procedure: unless these are explicitly		summarize the [RFC3263] procedure: unless these are explicitly
	encoded in the target URI, a transport is chosen using NAPTR records,		encoded in the target URI, a transport is chosen using NAPTR records,
	a port is chosen using SRV records, and an address is chosen using A		a port is chosen using SRV records, and an address is chosen using A
	or AAAA records.		or AAAA records.
	When communicating with another SSP, entities compliant to this		When communicating with another SSP, entities compliant to this
	document should select a TLS-protected transport for communication		document should select a TLS-protected transport for communication
	from the originating (or indirect) SSP to the receiving SSP if		from the Originating (or Indirect) SSP to the receiving SSP if
	available, as described further in Section 6.2.1.		available, as described further in Section 6.2.1.
	6.1.2.2. Routing Table		6.1.2.2. Routing Table
	If there are no End User ENUM records and the originating (or		If there are no End User ENUM records and the Originating (or
	indirect) SSP cannot discover the carrier-of-record or if the		Indirect) SSP cannot discover the carrier-of-record or if the
	originating (or indirect) SSP cannot reach the carrier-of-record via		Originating (or Indirect) SSP cannot reach the carrier-of-record via
	SIP peering, the originating (or indirect) SSP may deliver the call		SIP peering, the Originating (or Indirect) SSP may deliver the call
	to the PSTN or reject it. Note that the originating (or indirect)		to the PSTN or reject it. Note that the Originating (or Indirect)
	SSP may forward the call to another SSP for PSTN gateway termination		SSP may forward the call to another SSP for PSTN gateway termination
	by prior arrangement using the local SIP proxy routing table.		by prior arrangement using the local SIP proxy routing table.
	If so, the originating (or indirect) SSP rewrites the Request-URI to		If so, the Originating (or Indirect) SSP rewrites the Request-URI to
	address the gateway resource in the target SSP's domain and may		address the gateway resource in the Target SSP's domain and may
	forward the request on to that SSP using the procedures described in		forward the request on to that SSP using the procedures described in
	the remainder of these steps.		the remainder of these steps.
	6.1.2.3. LRF to LRF Routing		6.1.2.3. LRF to LRF Routing
	Communications between the LRF of two interconnecting SSPs may use		Communications between the LRF of two interconnecting SSPs may use
	DNS or statically provisioned IP Addresses for reachability. Other		DNS or statically provisioned IP addresses for reachability. Other
	inputs to determine the path may be code-based routing, method-based		inputs to determine the path may be code-based routing, method-based
	routing, Time of day, least cost and/or source-based routing.		routing, time of day, least cost and/or source-based routing.
	6.1.3. The Signaling Path Border Element (SBE)		6.1.3. The Signaling Path Border Element (SBE)
	The purpose of signaling function is to perform routing of SIP		The purpose of the Signaling Function is to perform routing of SIP
	messages as well as optionally implement security and policies on SIP		messages as well as optionally implement security and policies on SIP
	messages, and to assist in discovery/exchange of parameters to be		messages and to assist in discovery/exchange of parameters to be used
	used by the Media Function (MF). The signaling function performs the		by the Media Function (MF). The Signaling Function performs the
	routing of SIP messages. The SBE may be a B2BUA or it may act as a		routing of SIP messages. The SBE may be a back-to-back user agent
	SIP proxy. Optionally, an SF may perform additional functions such		(B2BUA) or it may act as a SIP proxy. Optionally, an SF may perform
	as Session Admission Control, SIP Denial of Service protection, SIP		additional functions such as Session Admission Control, SIP Denial-
	Topology Hiding, SIP header normalization, SIP security, privacy, and		of-Service protection, SIP Topology Hiding, SIP header normalization,
	encryption. The SF of an SBE can also process SDP payloads for media		SIP security, privacy, and encryption. The SF of an SBE can also
	information such as media type, bandwidth, and type of codec; then,		process SDP payloads for media information such as media type,
	communicate this information to the media function.		bandwidth, and type of codec; then, communicate this information to
			the media function.
	6.1.3.1. Establishing a Trusted Relationship		6.1.3.1. Establishing a Trusted Relationship
	Depending on the security needs and trust relationships between SSPs,		Depending on the security needs and trust relationships between SSPs,
	different security mechanisms can be used to establish SIP calls.		different security mechanisms can be used to establish SIP calls.
	These are discussed in the following subsections.		These are discussed in the following subsections.
	6.1.3.2. IPSec		6.1.3.2. 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 a
	security mechanism instead of TLS. However, such IPSec use should be		security mechanism instead of TLS. However, such IPsec use should be
	the subject of a future document as additional specification is		the subject of a future document as additional specification is
	necessary to use IPSec properly and effectively.		necessary to use IPsec properly and effectively.
	6.1.3.3. Co-Location		6.1.3.3. Co-Location
	In this scenario the SFs are co-located in a physically secure		In this scenario, the SFs are co-located in a physically secure
	location and/or are members of a segregated network. In this case		location and/or are members of a segregated network. In this case,
	messages between the originating and terminating SSPs could be sent		messages between the Originating and Terminating SSPs could be sent
	as clear text (unencrypted). However, even in these semi-trusted co-		as clear text (unencrypted). However, even in these semi-trusted co-
	location facilities, other security or access control mechanisms may		location facilities, other security or access control mechanisms may
	be appropriate, such as IP access control lists or other mechanisms.		be appropriate, such as IP access control lists or other mechanisms.
	6.1.3.4. Sending the SIP Request		6.1.3.4. Sending the SIP Request
	Once a trust relationship between the peers is established, the		Once a trust relationship between the peers is established, the
	originating (or indirect) SSP sends the request.		Originating (or Indirect) SSP sends the request.
	6.2. Target SSP Procedures		6.2. Target SSP Procedures
	This section describes the Target SSP Procedures.		This section describes the Target SSP Procedures.
	6.2.1. TLS		6.2.1. TLS
	The section defines the usage of TLS between two SSPs [RFC5246]		The section defines the usage of TLS between two SSPs [RFC5246]
	[RFC5746] [RFC5878]. When the receiving SSP receives a TLS client		[RFC5746] [RFC5878]. When the receiving SSP receives a TLS client
	hello, it responds with its certificate. The Target SSP certificate		hello, it responds with its certificate. The Target SSP certificate
	should be valid and rooted in a well-known certificate authority.		should be valid and rooted in a well-known certificate authority.
	The procedures to authenticate the SSP's originating domain are		The procedures to authenticate the SSP's originating domain are
	specified in [RFC5922].		specified in [RFC5922].
	The SF of the Target SSP verifies that the Identity header is valid,		The SF of the Target SSP verifies that the Identity header is valid,
	corresponds to the message, corresponds to the Identity-Info header,		corresponds to the message, corresponds to the Identity-Info header,
	and that the domain in the From header corresponds to one of the		and that the domain in the From header corresponds to one of the
	domains in the TLS client certificate.		domains in the TLS client certificate.
	As noted above in Section 6.1.3.2, some deployments may utilize IPSec		As noted above in Section 6.1.3.2, some deployments may utilize IPsec
	rather than TLS.		rather than TLS.
	6.2.2. Receive SIP Requests		6.2.2. Receive SIP Requests
	Once a trust relationship is established, the Target SSP is prepared		Once a trust relationship is established, the Target SSP is prepared
	to receive incoming SIP requests. For new requests (dialog forming		to receive incoming SIP requests. For new requests (dialog forming
	or not) the receiving SSP verifies if the target (request-URI) is a		or not), the receiving SSP verifies if the target (Request-URI) is a
	domain that for which it is responsible. For these requests, there		domain for which it is responsible. For these requests, there should
	should be no remaining Route header field values. For in-dialog		be no remaining Route header field values. For in-dialog requests,
	requests, the receiving SSP can verify that it corresponds to the		the receiving SSP can verify that it corresponds to the top-most
	top-most Route header field value.		Route header field value.
	The receiving SSP may reject incoming requests due to local policy.		The receiving SSP may reject incoming requests due to local policy.
	When a request is rejected because the originating (or indirect) SSP		When a request is rejected because the Originating (or Indirect) SSP
	is not authorized to peer, the receiving SSP should respond with a		is not authorized to peer, the receiving SSP should respond with a
	403 response with the reason phrase "Unsupported Peer".		403 response with the reason phrase "Unsupported Peer".
	6.3. Data Path Border Element (DBE)		6.3. Data Path Border Element (DBE)
	The purpose of the DBE [RFC5486] is to perform media related		The purpose of the DBE [RFC5486] is to perform media-related
	functions such as media transcoding and media security implementation		functions such as media transcoding and media security implementation
	between two SSPs.		between two SSPs.
	An example of this is to transform a voice payload from one codec		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		(e.g., G.711) to another (e.g., EvRC). Additionally, the MF may
	perform media relaying, media security [RFC3711], privacy, and		perform media relaying, media security [RFC3711], privacy, and
	encryption.		encryption.
	7. Address Space Considerations		7. Address Space Considerations
	Peering must occur in a common IP address space, which is defined by		Peering must occur in a common IP address space, which is defined by
	the federation, which may be entirely on the public Internet, or some		the federation, which may be entirely on the public Internet, or some
	private address space [RFC1918]. The origination or termination		private address space [RFC1918]. The origination or termination
	networks may or may not entirely be in the same address space. If		networks may or may not entirely be in the same address space. If
	they are not, then a network address translation (NAT) or similar may		they are not, then a Network Address Translation (NAT) or similar may
	be needed before the signaling or media is presented correctly to the		be needed before the signaling or media is presented correctly to the
	federation. The only requirement is that all associated entities		federation. The only requirement is that all associated entities
	across the peering interface are reachable.		across the peering interface are reachable.
	8. Acknowledgments		8. Acknowledgments
	The working group would like to thank John Elwell, Otmar Lendl, Rohan		The working group would like to thank John Elwell, Otmar Lendl, Rohan
	Mahy, Alexander Mayrhofer, Jim McEachern, Jean-Francois Mule,		Mahy, Alexander Mayrhofer, Jim McEachern, Jean-Francois Mule,
	Jonathan Rosenberg, and Dan Wing for their valuable contributions to		Jonathan Rosenberg, and Dan Wing for their valuable contributions to
	various versions of this document.		various versions of this document.
	9. IANA Considerations		9. Security Considerations
	This memo includes no request to IANA.
	10. Security Considerations
	The level (or types) of security mechanisms implemented between		The level (or types) of security mechanisms implemented between
	peering providers is in practice dependent upon on the underlying		peering providers is, in practice, dependent upon on the underlying
	physical security of SSP connections. This means, as noted in		physical security of SSP connections. This means, as noted in
	Section 6.1.3.3, whether peering equipment is in a secure facility or		Section 6.1.3.3, whether peering equipment is in a secure facility or
	not may bear on other types of security mechanisms which may be		not may bear on other types of security mechanisms that may be
	appropriate. Thus, if two SSPs peered across public Internet links,		appropriate. Thus, if two SSPs peered across public Internet links,
	they are likely to use IPSec or TLS since the link between the two		they are likely to use IPsec or TLS since the link between the two
	domains should be considered untrusted.		domains should be considered untrusted.
	Many detailed and highly relevant security requirements for SPEERMINT		Many detailed and highly relevant security requirements for SPEERMINT
	have been documented in Section 5 of		have been documented in Section 5 of [RFC6271]. As a result, that
	[I-D.ietf-speermint-requirements]. As a result, that document should		document should be considered required reading.
	be considered required reading.
	Additional and important security considerations have been documented		Additional and important security considerations have been documented
	separately in [I-D.ietf-speermint-voipthreats]. This document		separately in [RFC6404]. This document describes the many relevant
	describes the many relevant security threats to SPEERMINT, as well		security threats to SPEERMINT, as well the relevant countermeasures
	the relevant countermeasures and security protections which are		and security protections that are recommended to combat any potential
	recommended to combat any potential threats or other risks. This		threats or other risks. This includes a wide range of detailed
	includes a wide range of detailed threats in Section 2 of		threats in Section 2 of [RFC6404]. It also includes key requirements
	[I-D.ietf-speermint-voipthreats]. It also includes key requirements		in Section 3.1 of [RFC6404], such as the requirement for the LUF and
	in Section 3.1 of [I-D.ietf-speermint-voipthreats], such as the		LRF to support mutual authentication for queries, among other
	requirement for the LUF and LRF to support mutual authentication for		requirements which are related to [RFC6271]. Section 3.2 of
	queries, among other requirements which are related to		[RFC6404] explains how to meet these security requirements, and then
	[I-D.ietf-speermint-requirements]. Section 3.2 of		Section 4 explores a wide range of suggested countermeasures.
	[I-D.ietf-speermint-voipthreats] explains how to meet these security
	requirements, and then Section 4 explores a wide range of suggested
	countermeasures.
	11. Contributors		10. Contributors
	Mike Hammer		Mike Hammer
	Cisco Systems		Cisco Systems
			Herndon, VA
	Herndon, VA - USA		US
			EMail: mhammer@cisco.com
	Email: mhammer@cisco.com
	--------------------------------------------------------------
	Hadriel Kaplan		Hadriel Kaplan
	Acme Packet		Acme Packet
			Burlington, MA
	Burlington, MA - USA		US
			EMail: hkaplan@acmepacket.com
	Email: hkaplan@acmepacket.com
	--------------------------------------------------------------
	Sohel Khan, Ph.D.		Sohel Khan, Ph.D.
	Comcast Cable		Comcast Cable
			Philadelphia, PA
	Philadelphia, PA - USA		US
	Email: sohel_khan@cable.comcast.com		EMail: sohel_khan@cable.comcast.com
	--------------------------------------------------------------
	Reinaldo Penno		Reinaldo Penno
	Juniper Networks		Juniper Networks
			Sunnyvale, CA
	Sunnyvale, CA - USA		US
			EMail: rpenno@juniper.net
	Email: rpenno@juniper.net
	--------------------------------------------------------------
	David Schwartz		David Schwartz
	XConnect Global Networks		XConnect Global Networks
			Jerusalem
	Jerusalem - Israel		Israel
			EMail: dschwartz@xconnnect.net
	Email: dschwartz@xconnnect.net
	--------------------------------------------------------------
	Rich Shockey		Rich Shockey
	Shockey Consulting		Shockey Consulting
			US
	USA		EMail: Richard@shockey.us
	Email: Richard@shockey.us
	--------------------------------------------------------------
	Adam Uzelac		Adam Uzelac
	Global Crossing		Global Crossing
			Rochester, NY
			US
			EMail: adam.uzelac@globalcrossing.com
	Rochester, NY - USA		11. References
	Email: adam.uzelac@globalcrossing.com
	12. Change Log
	NOTE TO RFC EDITOR: PLEASE REMOVE THIS SECTION PRIOR TO PUBLICATION.
	o 19: Additional change to the IPSec section at Jari Arkko's
	request.
	o 18: Made several changes based on feedback from Adrian Farrel,
	Bert Wijnen, Dan Romascanu, Avshalom Houri, Russ Housley, Sean
	Turner, Tim Polk, and Russ Mundy during IESG review.
	o 17: Misc. updates at the request of Gonzalo, the RAI AD, in order
	to clear his review and move to the IESG. This included adding
	terminology from RFC 5486 and expanding the document name.
	o 16: Yes, one final outdated reference to fix.
	o 15: Doh! Uploaded the wrong doc to create -14. Trying again. :-)
	o 14: WGLC ended. Ran final nits check prior to sending proto to
	the AD and sending the doc to the IESG. Found a few very minor
	nits, such as capitalization and replacement of an obsoleted RFC,
	which were corrected per nits tool recommendation. The -14 now
	moves to the AD and the IESG.
	o 13: Closed out all remaining tickets, resolved all editorial
	notes.
	o 12: Closed out several open issues. Properly XML-ized all
	references. Updated contributors list.
	o 11: Quick update to refresh the I-D since it expired, and cleaned
	up some of the XML for references. A real revision is coming
	soon.
	13. References
	13.1. Normative References
	[I-D.ietf-speermint-requirements]
	Mule, J., "Requirements for SIP-based Session Peering",
	draft-ietf-speermint-requirements-10 (work in progress),
	October 2010.
	[I-D.ietf-speermint-voipthreats]		11.1. Normative References
	Seedorf, J., Niccolini, S., Chen, E., and H. Scholz,
	"Session Peering for Multimedia Interconnect (SPEERMINT)
	Security Threats and Suggested Countermeasures",
	draft-ietf-speermint-voipthreats-07 (work in progress),
	January 2011.
	[RFC1035] Mockapetris, P., "Domain names - implementation and		[RFC1035] Mockapetris, P., "Domain names - implementation and
	specification", STD 13, RFC 1035, November 1987.		specification", STD 13, RFC 1035, November 1987.
	[RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and		[RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
	E. Lear, "Address Allocation for Private Internets",		E. Lear, "Address Allocation for Private Internets",
	BCP 5, RFC 1918, February 1996.		BCP 5, RFC 1918, February 1996.
	[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,		[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
	A., Peterson, J., Sparks, R., Handley, M., and E.		A., Peterson, J., Sparks, R., Handley, M., and E.
	skipping to change at page 17, line 25		skipping to change at page 14, line 39
	June 2002.		June 2002.
	[RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation		[RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation
	Protocol (SIP): Locating SIP Servers", RFC 3263,		Protocol (SIP): Locating SIP Servers", RFC 3263,
	June 2002.		June 2002.
	[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.		[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
	Jacobson, "RTP: A Transport Protocol for Real-Time		Jacobson, "RTP: A Transport Protocol for Real-Time
	Applications", STD 64, RFC 3550, July 2003.		Applications", STD 64, RFC 3550, July 2003.
	[RFC3761] Faltstrom, P. and M. Mealling, "The E.164 to Uniform
	Resource Identifiers (URI) Dynamic Delegation Discovery
	System (DDDS) Application (ENUM)", RFC 3761, April 2004.
	[RFC3764] Peterson, J., "enumservice registration for Session		[RFC3764] Peterson, J., "enumservice registration for Session
	Initiation Protocol (SIP) Addresses-of-Record", RFC 3764,		Initiation Protocol (SIP) Addresses-of-Record", RFC 3764,
	April 2004.		April 2004.
	[RFC3861] Peterson, J., "Address Resolution for Instant Messaging		[RFC3861] Peterson, J., "Address Resolution for Instant Messaging
	and Presence", RFC 3861, August 2004.		and Presence", RFC 3861, August 2004.
	[RFC3953] Peterson, J., "Telephone Number Mapping (ENUM) Service		[RFC3953] Peterson, J., "Telephone Number Mapping (ENUM) Service
	Registration for Presence Services", RFC 3953,		Registration for Presence Services", RFC 3953,
	January 2005.		January 2005.
	skipping to change at page 18, line 17		skipping to change at page 15, line 31
	Protocol (SIP) Session Border Control (SBC) Deployments",		Protocol (SIP) Session Border Control (SBC) Deployments",
	RFC 5853, April 2010.		RFC 5853, April 2010.
	[RFC5878] Brown, M. and R. Housley, "Transport Layer Security (TLS)		[RFC5878] Brown, M. and R. Housley, "Transport Layer Security (TLS)
	Authorization Extensions", RFC 5878, May 2010.		Authorization Extensions", RFC 5878, May 2010.
	[RFC5922] Gurbani, V., Lawrence, S., and A. Jeffrey, "Domain		[RFC5922] Gurbani, V., Lawrence, S., and A. Jeffrey, "Domain
	Certificates in the Session Initiation Protocol (SIP)",		Certificates in the Session Initiation Protocol (SIP)",
	RFC 5922, June 2010.		RFC 5922, June 2010.
	13.2. Informative References		[RFC6116] Bradner, S., Conroy, L., and K. Fujiwara, "The E.164 to
			Uniform Resource Identifiers (URI) Dynamic Delegation
			Discovery System (DDDS) Application (ENUM)", RFC 6116,
			March 2011.
	[I-D.ietf-speermint-voip-consolidated-usecases]		[RFC6271] Mule, J-F., "Requirements for SIP-Based Session Peering",
	Uzelac, A. and Y. Lee, "VoIP SIP Peering Use Cases",		RFC 6271, June 2011.
	draft-ietf-speermint-voip-consolidated-usecases-18 (work
	in progress), April 2010.		[RFC6404] Seedorf, J., Niccolini, S., Chen, E., and H. Scholz,
			"Session PEERing for Multimedia INTerconnect (SPEERMINT)
			Security Threats and Suggested Countermeasures", RFC 6404,
			November 2011.
			11.2. Informative References
	[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.		[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
	Norrman, "The Secure Real-time Transport Protocol (SRTP)",		Norrman, "The Secure Real-time Transport Protocol (SRTP)",
	RFC 3711, March 2004.		RFC 3711, March 2004.
			[RFC6405] Uzelac, A., Ed. and Y. Lee, Ed., "Voice over IP (VoIP) SIP
			Peering Use Cases", RFC 6405, November 2011.
	Authors' Addresses		Authors' Addresses
	Daryl Malas (editor)		Daryl Malas (editor)
	CableLabs		CableLabs
	Louisville, CO		Louisville, CO
	US		US
	Email: d.malas@cablelabs.com		EMail: d.malas@cablelabs.com
	Jason Livingood (editor)		Jason Livingood (editor)
	Comcast		Comcast
	Philadelphia, PA		Philadelphia, PA
	US		US
	Email: Jason_Livingood@cable.comcast.com		EMail: Jason_Livingood@cable.comcast.com
End of changes. 111 change blocks.
	362 lines changed or deleted		286 lines changed or added
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