< draft-ietf-ecrit-unauthenticated-access-08.txt		draft-ietf-ecrit-unauthenticated-access-09.txt >
	ECRIT H. Schulzrinne		ECRIT H. Schulzrinne
	Internet-Draft Columbia University		Internet-Draft Columbia University
	Intended status: Standards Track S. McCann		Intended status: Standards Track S. McCann
	Expires: April 22, 2014 Research in Motion UK Ltd		Expires: January 4, 2015 Research in Motion UK Ltd
	G. Bajko		G. Bajko
	Nokia		Nokia
	H. Tschofenig		H. Tschofenig
	Nokia Solutions and Networks
	D. Kroeselberg		D. Kroeselberg
	Siemens		Siemens
	October 19, 2013		July 3, 2014
	Extensions to the Emergency Services Architecture for dealing with		Extensions to the Emergency Services Architecture for dealing with
	Unauthenticated and Unauthorized Devices		Unauthenticated and Unauthorized Devices
	draft-ietf-ecrit-unauthenticated-access-08.txt		draft-ietf-ecrit-unauthenticated-access-09.txt
	Abstract		Abstract
	The IETF emergency services architecture assumes that the calling
	device has acquired rights to use the access network or that no
	authentication is required for the access network, such as for public
	wireless access points. Subsequent protocol interactions, such as
	obtaining location information, learning the address of the Public
	Safety Answering Point (PSAP) and the emergency call itself are
	largely decoupled from the underlying network access procedures.
	In some cases, however, the device does not have these credentials
	for network access, does not have a VoIP service provider, or the
	credentials have become invalid, e.g., because the user has exhausted
	their prepaid balance or the account has expired.
	With features provided by the Public Switched Telephone Network
	(PSTN) there is precedence for some of these use cases and the
	transition to IP-based emergency calling creates the desire to
	replicate functionality the PSTN already offers today. For example,
	in many countries persons seeking help are empowered to initiate
	emergency calls without having a Subscriber Identity Module (SIM) in
	their mobile phone.
	This document provides a problem statement, introduces terminology		This document provides a problem statement, introduces terminology
	and describes an extension for the base IETF emergency services		and describes an extension for the base IETF emergency services
	architecture to address these scenarios.		architecture to address cases where an emergency caller is not
			authenticated, has no identifiable service provider, or has no
			remaining credit with which to pay for access to the network.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
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	This Internet-Draft will expire on April 22, 2014.		This Internet-Draft will expire on January 4, 2015.
	Copyright Notice		Copyright Notice
	Copyright (c) 2013 IETF Trust and the persons identified as the		Copyright (c) 2014 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
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
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	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
	3. Use Case Categories . . . . . . . . . . . . . . . . . . . . . 5		3. Use Case Categories . . . . . . . . . . . . . . . . . . . . . 5
	4. ZBP Considerations . . . . . . . . . . . . . . . . . . . . . 11		4. ZBP Considerations . . . . . . . . . . . . . . . . . . . . . 11
	5. NASP Considerations . . . . . . . . . . . . . . . . . . . . . 11		5. NASP Considerations . . . . . . . . . . . . . . . . . . . . . 11
	5.1. End Host Profile . . . . . . . . . . . . . . . . . . . . 13		5.1. End Host Profile . . . . . . . . . . . . . . . . . . . . 14
	5.1.1. LoST Server Discovery . . . . . . . . . . . . . . . . 13		5.1.1. LoST Server Discovery . . . . . . . . . . . . . . . . 14
	5.1.2. ESRP Discovery . . . . . . . . . . . . . . . . . . . 13		5.1.2. ESRP Discovery . . . . . . . . . . . . . . . . . . . 14
	5.1.3. Location Determination and Location Configuration . . 14		5.1.3. Location Determination and Location Configuration . . 14
	5.1.4. Emergency Call Identification . . . . . . . . . . . . 14		5.1.4. Emergency Call Identification . . . . . . . . . . . . 14
	5.1.5. SIP Emergency Call Signaling . . . . . . . . . . . . 14		5.1.5. SIP Emergency Call Signaling . . . . . . . . . . . . 14
	5.1.6. Media . . . . . . . . . . . . . . . . . . . . . . . . 14		5.1.6. Media . . . . . . . . . . . . . . . . . . . . . . . . 15
	5.1.7. Testing . . . . . . . . . . . . . . . . . . . . . . . 14		5.1.7. Testing . . . . . . . . . . . . . . . . . . . . . . . 15
	5.2. IAP/ISP Profile . . . . . . . . . . . . . . . . . . . . . 14		5.2. IAP/ISP Profile . . . . . . . . . . . . . . . . . . . . . 15
	5.2.1. ESRP Discovery . . . . . . . . . . . . . . . . . . . 15		5.2.1. ESRP Discovery . . . . . . . . . . . . . . . . . . . 15
	5.2.2. Location Determination and Location Configuration . . 15		5.2.2. Location Determination and Location Configuration . . 15
	5.3. ESRP Profile . . . . . . . . . . . . . . . . . . . . . . 15		5.3. ESRP Profile . . . . . . . . . . . . . . . . . . . . . . 15
	5.3.1. Emergency Call Routing . . . . . . . . . . . . . . . 15		5.3.1. Emergency Call Routing . . . . . . . . . . . . . . . 15
	5.3.2. Emergency Call Identification . . . . . . . . . . . . 15		5.3.2. Emergency Call Identification . . . . . . . . . . . . 15
	5.3.3. SIP Emergency Call Signaling . . . . . . . . . . . . 15		5.3.3. SIP Emergency Call Signaling . . . . . . . . . . . . 16
	6. Lower Layer Considerations for NAA Case . . . . . . . . . . . 15		6. Lower Layer Considerations for NAA Case . . . . . . . . . . . 16
	6.1. Link Layer Emergency Indication . . . . . . . . . . . . . 17		6.1. Link Layer Emergency Indication . . . . . . . . . . . . . 17
	6.2. Securing Network Attachment in NAA Cases . . . . . . . . 18		6.2. Securing Network Attachment in NAA Cases . . . . . . . . 18
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 19		7. Security Considerations . . . . . . . . . . . . . . . . . . . 19
	8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20		8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20
	9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20		9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
	10. References . . . . . . . . . . . . . . . . . . . . . . . . . 20		10. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
	10.1. Normative References . . . . . . . . . . . . . . . . . . 20		10.1. Normative References . . . . . . . . . . . . . . . . . . 21
	10.2. Informative References . . . . . . . . . . . . . . . . . 21		10.2. Informative References . . . . . . . . . . . . . . . . . 22
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
	1. Introduction		1. Introduction
	Summoning police, the fire department or an ambulance in emergencies		Summoning police, the fire department or an ambulance in emergencies
	is one of the fundamental and most-valued functions of the telephone.		is one of the fundamental and most-valued functions of the telephone.
	As telephone functionality moves from circuit-switched telephony to		As telephone functionality moves from circuit-switched telephony to
	Internet telephony, its users rightfully expect that this core		Internet telephony, its users rightfully expect that this core
	functionality will continue to work at least as well as it has for		functionality will continue to work at least as well as it has for
	the older technology. New devices and services are being made		the older technology. New devices and services are being made
	available that could be used to make a request for help, which are		available that could be used to make a request for help, those
	not traditional telephones, and users are increasingly expecting them		devices are not traditional telephones, and users are increasingly
	to be used to place emergency calls.		expecting them to be used to place emergency calls.
	Roughly speaking, the IETF emergency services architecture (see		Roughly speaking, the IETF emergency services architecture (see
	[RFC6881] and [RFC6443]) divides responsibility for handling		[RFC6881] and [RFC6443]) divides responsibility for handling
	emergency calls between the access network (ISP), the application		emergency calls among the access network (ISP); the application
	service provider (ASP) that may be a VoIP service provider (VSP) and		service provider (ASP), which may be a VoIP service provider (VSP);
	the provider of emergency signaling services, the emergency service		and the provider of emergency signaling services, the emergency
	network (ESN). The access network may provide location information		service network (ESN). The access network may provide location
	to end systems, but does not have to provide any ASP signaling		information to end systems, but does not have to provide any ASP
	functionality. The emergency caller can reach the ESN either		signaling functionality. The emergency caller can reach the ESN
	directly or through the ASP's outbound proxy. Any of the three		either directly or through the ASP's outbound proxy. Any of the
	parties can provide the mapping from location to PSAP URI by offering		three parties can provide the mapping from location to PSAP URI by
	LoST [RFC5222] services.		offering LoST [RFC5222] services.
	In general, a set of automated configuration mechanisms allows a		In general, a set of automated configuration mechanisms allows a
	device to function in a variety of architectures, without the user		device to function in a variety of architectures, without the user
	being aware of the details on who provides location, mapping services		being aware of the details on who provides location, mapping services
	or call routing services. However, if emergency calling is to be		or call routing services. However, if emergency calling is to be
	supported when the calling device lacks access network authorization		supported when the calling device lacks access network authorization
	or does not have an ASP, one or more of the providers may need to		or does not have an ASP, one or more of the providers may need to
	provide additional services and functions.		provide additional services and functions.
	In all cases, the end device has to be able to perform a LoST lookup		In all cases, the end device has to be able to perform a LoST lookup
	and otherwise conduct the emergency call in the same manner as when		and otherwise conduct the emergency call in the same manner as when
	the three exceptional conditions discussed below do not apply.		the three exceptional conditions discussed below do not apply.
	We distinguish between three conditions:		We distinguish among three conditions:
	No Access Authentication (NAA): In the NAA case, the emergency		No Access Authentication (NAA): In the NAA case, the emergency
	caller does not posses valid credentials for the access network.		caller does not posses valid credentials for the access network.
	This includes the case where the access network allows pay-per-		This includes the case where the access network allows pay-per-
	use, as is common for wireless hotspots, but there is insufficient		use, as is common for wireless hotspots, but there is insufficient
	time to enter credit card details and other registration		time to enter credit card details and other registration
	information required for access. It also covers all cases where		information required for access. It also covers all cases where
	either no credentials are available at all, or the available		either no credentials are available at all, or the available
	credentials do not work for the given IAP/ISP. As a result, the		credentials do not work for the given IAP/ISP. As a result, the
	NAA case basically combines the below NASP and ZBP cases, but at		NAA case basically combines the below NASP and ZBP cases, but at
	skipping to change at page 4, line 36 ¶		skipping to change at page 4, line 20 ¶
	Note: The interoperability need is increased with this scenario		Note: The interoperability need is increased with this scenario
	since the client software used by the emergency caller must be		since the client software used by the emergency caller must be
	compatible with the protocols and extensions deployed by the ESN.		compatible with the protocols and extensions deployed by the ESN.
	Zero-balance ASP (ZBP): In the case of zero-balance ASP, the ASP can		Zero-balance ASP (ZBP): In the case of zero-balance ASP, the ASP can
	authenticate the caller, but the caller is not authorized to use		authenticate the caller, but the caller is not authorized to use
	ASP services, e.g., because the contract has expired or the		ASP services, e.g., because the contract has expired or the
	prepaid account for the customer has been depleted.		prepaid account for the customer has been depleted.
	These three cases are not mutually exclusive. A caller in need for		These three cases are not mutually exclusive. A caller in need of
	help may find himself/herself in, for example, a NAA and NASP		help may, for example, be in a NAA and NASP situation, as explained
	situation, as explained in more details in Figure 1. Depending on		in more detail in Figure 1. Depending on local policy and
	local policy and regulations, it may not be possible to place		regulations, it may not be possible to place emergency calls in the
	emergency calls in the NAA case. Unless local regulations require		NAA case. Unless local regulations require user identification, it
	user identification, it should always be possible to place calls in		should always be possible to place calls in the NASP case, with
	the NASP case, with minimal impact on the ISP. Unless the ESN		minimal impact on the ISP. Unless the ESN requires that all calls
	requires that all calls traverse a known set of VSPs, it is		traverse a known set of VSPs, it is technically possible to let a
	technically possible to let a caller place an emergency call in the		caller place an emergency call in the ZBP case. We discuss each case
	ZBP case. We discuss each case in more details in Section 3.		in more details in Section 3.
	Note: At the time of writing there is no regulation in place that		Note: At the time of writing there is no regulation in place that
	demands the functionality described in this memo. SDOs have started		demands the functionality described in this memo. SDOs have started
	their work on this subject in a proactive fashion in the anticipation		their work on this subject in a proactive fashion in the anticipation
	that national regulation will demand it for a subset of network		that national regulation will demand it for a subset of network
	environments.		environments.
	As mentioned in the abstract some of the functionality provided in		As mentioned in the abstract some of the functionality provided in
	this document is already available in the PSTN. Consequently, there		this document is already available in the PSTN. Consequently, there
	is real-world experience available and not all of it is positive.		is real-world experience available and not all of it is positive.
	skipping to change at page 5, line 41 ¶		skipping to change at page 5, line 24 ¶
	This document reuses terminology from [RFC5687] and [RFC5012], namely		This document reuses terminology from [RFC5687] and [RFC5012], namely
	Internet Access Provider (IAP), Internet Service Provider (ISP),		Internet Access Provider (IAP), Internet Service Provider (ISP),
	Application Service Provider (ASP), Voice Service Provider (VSP),		Application Service Provider (ASP), Voice Service Provider (VSP),
	Emergency Service Routing Proxy (ESRP), Public Safety Answering Point		Emergency Service Routing Proxy (ESRP), Public Safety Answering Point
	(PSAP), Location Configuration Server (LCS), (emergency) service dial		(PSAP), Location Configuration Server (LCS), (emergency) service dial
	string, and (emergency) service identifier.		string, and (emergency) service identifier.
	3. Use Case Categories		3. Use Case Categories
	On a very high-level, the steps to be performed by an end host not		On a very high-level, the steps to be performed by an end host that
	being attached to the network and the user starting to make an		is not attached to the network and the user starting to make an
	emergency call are the following:		emergency call are the following:
	Link Layer Attachment: Some networks have added support for		Link Layer Attachment: Some networks have added support for
	unauthenticated emergency access, some other type of networks		unauthenticated emergency access, some other type of networks
	advertise these capabilities using layer beacons. The end host		advertise these capabilities using layer beacons. The end host
	learns about these unauthenticated emergency services capabilities		learns about these unauthenticated emergency services capabilities
	either from the link layer type or from advertisement.		either from the link layer type or from advertisement.
	The end host uses the link layer specific network attachment		The end host uses the link layer specific network attachment
	procedures defined for unauthenticated network access in order to		procedures defined for unauthenticated network access in order to
	skipping to change at page 7, line 39 ¶		skipping to change at page 7, line 20 ¶
	Abbreviations:		Abbreviations:
	LLA: Link Layer Attachment		LLA: Link Layer Attachment
	ES: Emergency Services		ES: Emergency Services
	Figure 1: Flow Diagram: NAA, ZBP, and NSAP Scenarios.		Figure 1: Flow Diagram: NAA, ZBP, and NSAP Scenarios.
	The diagrams below highlight the most important steps for the three		The diagrams below highlight the most important steps for the three
	cases.		cases.
	+-----Y		+-----Y
	|Start|		|Start|
	`...../		`...../
	|		|
	| No		| No
	| credentials		| credentials
	| for network access		| for network access
	| available		| available
	v		v
	..............		..............
	| Idle: Wait |		| Idle: Wait |
	| for ES Call|		| for ES Call|
	| Initiation |		| Initiation |
	"------------'		"------------'
	|		|
	|		|
	|		|
	v		v
	--		--
	// --		// --
	/ --		/ --
	// Is --		// Is --
	/ emergency --		/ emergency --
	| service | NO +--------+		| service | NO +--------+
	| network |------>| Call |		| network |------>| Call |
	| attachment | Failed |		| attachment | Failed |
	\ possible? / `......./		\ possible? / `......./
	\ //		\ //
	\\ //		\\ //
	\ //		\ //
	\--/		\--/
	|		|
	| YES		| YES
	|		|
	|		|
	v		v
	+------------+		+------------+
	| Execute |		| Execute |
	| NAA |		| NAA |
	| Procedures |		| Procedures |
	+------------+		+------------+
	|		|
	| Network		| Network
	| attachment		| attachment
	| in progress		| in progress
	v		v
	/--\ Continue		/--\ Continue
	| | with		| | with
	| | application		| | application
	\--/ layer interaction		\--/ layer interaction
	Figure 2: Flow Diagram: NAA Scenario.		Figure 2: Flow Diagram: NAA Scenario.
	+-----+		+-----+
	+------------|Start|-----------------+		+------------|Start|-----------------+
	| `...../ |		| `...../ |
	v v		v v
	+------------+ +----------------+		+------------+ +----------------+
	| NAA | | Regular |		| NAA | | Regular |
	| Procedures | | Network Access |		| Procedures | | Network Access |
	+------------+ | Procedures |		+------------+ | Procedures |
	| +----------------+		| +----------------+
	| |		| |
	| |		| |
	----------------o--------------------+		----------------o--------------------+
	|		|
	|		|
	|		|
	|		|
	Network		Network
	Attachment		Attachment
	Completed		Completed
	|		|
	|		|
	|		|
	|		|
	v		v
	+------------+ +---------+		+------------+ +---------+
	| ASP | NO | See |		| ASP | NO | See |
	| Configured?|----->| main |		| Configured?|----->| main |
	+------------+ | diagram |		+------------+ | diagram |
	| `......../		| `......../
	|		|
	| YES		| YES
	|		|
	v		v
	//----		//----
	/ --		/ --
	// --		// --
	/ - +---------+		/ - +---------+
	| Authorization| YES | See |		| Authorization| YES | See |
	| for making |------>| main |		| for making |------>| main |
	| ES call | | diagram |		| ES call | | diagram |
	\ with / `......../		\ with / `......../
	\ VSP/ASP? //		\ VSP/ASP? //
	\\ //		\\ //
	\ //		\ //
	\--/		\--/
	|		|
	| NO		| NO
	|		|
	|		|
	v		v
	+------------+		+------------+
	| Execute |		| Execute |
	| ZBP |		| ZBP |
	| Procedures |		| Procedures |
	+------------+		+------------+
	|		|
	| Call		| Call
	| in progress		| in progress
	|		|
	v		v
	+--------+		+--------+
	| Call |		| Call |
	Success|		Success|
	`......./		`......./
	Figure 3: Flow Diagram: ZBP Scenario.		Figure 3: Flow Diagram: ZBP Scenario.
	+-----+		+-----+
	+------------|Start|-----------------+		+------------|Start|-----------------+
	| `...../ |		| `...../ |
	v v		v v
	+------------+ +----------------+		+------------+ +----------------+
	| NAA | | Regular |		| NAA | | Regular |
	| Procedures | | Network Access |		| Procedures | | Network Access |
	+------------+ | Procedures |		+------------+ | Procedures |
	| +----------------+		| +----------------+
	| |		| |
	| |		| |
	----------------o--------------------+		----------------o--------------------+
	|		|
	|		|
	|		|
	|		|
	Network		Network
	Attachment		Attachment
	Completed		Completed
	|		|
	|		|
	|		|
	|		|
	v		v
	+------------+ +---------+		+------------+ +---------+
	| ASP | YES | See |		| ASP | YES | See |
	| Configured?|----->| main |		| Configured?|----->| main |
	+------------+ | diagram |		+------------+ | diagram |
	| `......../		| `......../
	|		|
	| NO		| NO
	|		|
	v		v
	+------------+		+------------+
	| Execute |		| Execute |
	| NASP |		| NASP |
	| Procedures |		| Procedures |
	+------------+		+------------+
	|		|
	| Call		| Call
	| in progress		| in progress
	|		|
	v		v
	+--------+		+--------+
	| Call |		| Call |
	Success|		Success|
	`......./		`......./
	Figure 4: Flow Diagram: NASP Scenario.		Figure 4: Flow Diagram: NASP Scenario.
	The "No Access Authentication (NAA)" procedures are described in		The "No Access Authentication (NAA)" procedures are described in
	Section 6. The "Zero-balance ASP (ZBP)" procedures are described in		Section 6. The "Zero-balance ASP (ZBP)" procedures are described in
	Section 4. The "No ASP (NASP)" procedures are described in		Section 4. The "No ASP (NASP)" procedures are described in
	Section 5. The Phone BCP procedures are described in [RFC6881]. The		Section 5. The Phone BCP procedures are described in [RFC6881]. The
	"Link Layer Attachment (LLA)" procedures are not described in this		"Link Layer Attachment (LLA)" procedures are not described in this
	document since they are specific to the link layer technology in use.		document since they are specific to the link layer technology in use.
	skipping to change at page 12, line 43 ¶		skipping to change at page 13, line 5 ¶
	o The PSAP evaluates the initial INVITE and aims to complete the		o The PSAP evaluates the initial INVITE and aims to complete the
	call setup.		call setup.
	o Finally, when the call setup is completed media traffic can be		o Finally, when the call setup is completed media traffic can be
	exchanged between the PSAP and the SIP UA.		exchanged between the PSAP and the SIP UA.
	For editorial reasons the end-to-end SIP and media exchange between		For editorial reasons the end-to-end SIP and media exchange between
	the PSAP and SIP UA are not shown in Figure 5.		the PSAP and SIP UA are not shown in Figure 5.
	+-------+		+-------+
	| PSAP |		| PSAP |
	| |		| |
	+-------+		+-------+
	^		^
	| (8)		| (8)
	|		|
	+----------+(7) +----------+		+----------+(7) +----------+
	| LoST |<-->| ESRP |		| LoST |<-->| ESRP |
	| Server | | |		| Server | | |
	+----------+ +----------+		+----------+ +----------+
	^ ^		^ ^
	+----------------+----------------|--------------+		+----------------+----------------|--------------+
	| ISP | | |		| ISP | | |
	|+----------+ | | +----------+|		|+----------+ | | +----------+|
	|| LCS-ISP | (3)| | | DHCP ||		|| LCS-ISP | (3)| | | DHCP ||
	|| |<-+ | | | Server ||		|| |<-+ | | | Server ||
	|+----------+ | | | +----------+|		|+----------+ | | | +----------+|
	+-------^------+-+----------------|-----------^--+		+-------^------+-+----------------|-----------^--+
	+-------|------+-+----------------|-----------|--+		+-------|------+-+----------------|-----------|--+
	| IAP | (4) | |(5) | | |		| IAP | (4) | |(5) | | |
	| V | | | | |		| V | | | | |
	|+----------+ | | | | |		|+----------+ | | | | |
	|| LCS-IAP | | | +--------+ | | |		|| LCS-IAP | | | +--------+ | | |
	|| | | | | Link | |(6) | |		|| | | | | Link | |(6) | |
	|+----------+ | | | Layer | | | |		|+----------+ | | | Layer | | | |
	| | | | Device | | (2)| |		| | | | Device | | (2)| |
	| | | +--------+ | | |		| | | +--------+ | | |
	| | | ^ | | |		| | | ^ | | |
	| | | | | | |		| | | | | | |
	+--------------+-|-------|--------|-----------|--+		+--------------+-|-------|--------|-----------|--+
	| | | | |		| | | | |
	| | (1)| | |		| | (1)| | |
	| | | | |		| | | | |
	| | | +----+ |		| | | +----+ |
	| | v | |		| | v | |
	| | +----------+ |		| | +----------+ |
	| +->| End |<-------------+		| +->| End |<-------------+
	+___>| Host |		+___>| Host |
	+----------+		+----------+
	Figure 5: Architectural Overview		Figure 5: Architectural Overview
	Note: Figure 5 does not indicate who operates the ESRP and the LoST		Note: Figure 5 does not indicate who operates the ESRP and the LoST
	server. Various deployment options exist.		server. Various deployment options exist.
	5.1. End Host Profile		5.1. End Host Profile
	5.1.1. LoST Server Discovery		5.1.1. LoST Server Discovery
	skipping to change at page 16, line 4 ¶		skipping to change at page 16, line 15 ¶
	5.3.3. SIP Emergency Call Signaling		5.3.3. SIP Emergency Call Signaling
	SIP signaling capabilities [RFC3261] are REQUIRED for the ESRP. The		SIP signaling capabilities [RFC3261] are REQUIRED for the ESRP. The
	ESRP MUST process the messages sent by the client, according to		ESRP MUST process the messages sent by the client, according to
	Section 5.1.5.		Section 5.1.5.
	Furthermore, if a PSAP wants to support NASP calls, then it MUST NOT		Furthermore, if a PSAP wants to support NASP calls, then it MUST NOT
	restrict incoming calls to a particular set of ASPs.		restrict incoming calls to a particular set of ASPs.
	6. Lower Layer Considerations for NAA Case		6. Lower Layer Considerations for NAA Case
	Some networks have added support for unauthenticated emergency		Some networks have added support for unauthenticated emergency
	access, some other type of networks advertise these capabilities		access, some other type of networks advertise these capabilities
	using layer beacons. The end host learns about these unauthenticated		using layer beacons. The end host learns about these unauthenticated
	emergency services capabilities either from the link layer type or		emergency services capabilities either from the link layer type or
	from advertisement.		from advertisement.
	It is important to highlight that the NAA case is inherently a layer		It is important to highlight that the NAA case is inherently a layer
	2 problem, and the general form of the solution is to provide an		2 problem, and the general form of the solution is to provide an
	"emergency only" access type, with appropriate limits/monitoring to		"emergency only" access type, with appropriate limits/monitoring to
	prevent abuse. The described mechanisms are informative in nature		prevent abuse. The described mechanisms are informative in nature
	since the relationship to the IETF emergency is only indirect, namely		since the relationship to the IETF emergency services architecture is
	via some protocols developed within the IETF (e.g., EAP and EAP		only indirect, namely via some protocols developed within the IETF
	methods) that require extensions to support this functionality.		(e.g., EAP and EAP methods) that require extensions to support this
			functionality.
	This section discusses different methods to indicate an emergency		This section discusses different methods to indicate an emergency
	service request as part of network attachment. It provides some		service request as part of network attachment. It provides some
	general considerations and recommendations that are not specific to		general considerations and recommendations that are not specific to
	the access technology.		the access technology.
	To perform network attachment and get access to the resources		To perform network attachment and get access to the resources
	provided by an IAP/ISP, the end host uses access technology specific		provided by an IAP/ISP, the end host uses access technology specific
	network attachment procedures, including for example network		network attachment procedures, including for example network
	detection and selection, authentication, and authorization. For		detection and selection, authentication, and authorization. For
	initial network attachment of an emergency service requester, the		initial network attachment of an emergency service requester, the
	method of how the emergency indication is given to the IAP/ISP is		method of how the emergency indication is given to the IAP/ISP is
	specific to the access technology. However, a number of general		specific to the access technology. However, a number of general
	approaches can be identified:		approaches can be identified:
	Link layer emergency indication: The end host provides an		Link layer emergency indication: The end host provides an
	indication, e.g., an emergency parameter or flag, as part of the		indication, e.g., an emergency parameter or flag, as part of the
	link layer signaling for initial network attachment. Examples		link layer signaling for initial network attachment. Examples
	include an emergency bit signalled in the IEEE 802.16-2009		include an emergency bit signalled in the IEEE 802.16-2009
	wireless link. In IEEE 802.11 WLAN, an emergency support		wireless link. In IEEE 802.11 WLAN, an emergency support
	indicator allows the STA to download before association an NAI		indicator allows the station (i.e., end host in this context) to
			download before association a Network Access Identifier (NAI),
	which it can use to request server side authentication only for an		which it can use to request server side authentication only for an
	802.1x network.		802.1x network.
	Higher-layer emergency indication: Typically, emergency indication		Higher-layer emergency indication: Typically, emergency indication
	is provided in the network access authentication procedure. The		is provided in the network access authentication procedure. The
	emergency caller's end host provides an indication as part of the		emergency caller's end host provides an indication as part of the
	access authentication exchanges. Authentication via the		access authentication exchanges. Authentication via the
	Extensible Authentication Protocol (EAP) [RFC3748] is of		Extensible Authentication Protocol (EAP) [RFC3748] is of
	particular relevance here. Examples are the EAP NAI decoration		particular relevance here. Examples are the EAP NAI decoration
	used in WiMAX networks and modification of the authentication		used in WiMAX networks and modification of the authentication
	skipping to change at page 19, line 27 ¶		skipping to change at page 19, line 42 ¶
	certificate.		certificate.
	7. Security Considerations		7. Security Considerations
	The security threats discussed in [RFC5069] are applicable to this		The security threats discussed in [RFC5069] are applicable to this
	document.		document.
	There are a couple of new vulnerabilities raised with unauthenticated		There are a couple of new vulnerabilities raised with unauthenticated
	emergency services in NASP/NAA cases since the PSAP operator will		emergency services in NASP/NAA cases since the PSAP operator will
	typically not possess any identity information about the emergency		typically not possess any identity information about the emergency
	call via the signaling path itself. In countries where this		caller via the signaling path itself. In countries where this
	functionality is used for GSM networks today this has lead to a		functionality is used for GSM networks today this has lead to a
	significant amount of misuse.		significant amount of misuse.
	In the context of NAA, the IAP and the ISP will probably want to make		In the context of NAA, the IAP and the ISP will probably want to make
	sure that the claimed emergency caller indeed performs an emergency		sure that the claimed emergency caller indeed performs an emergency
	call rather than using the network for other purposes, and thereby		call rather than using the network for other purposes, and thereby
	acting fraudulent by skipping any authentication, authorization and		acting fraudulent by skipping any authentication, authorization and
	accounting procedures. By restricting access of the unauthenticated		accounting procedures. By restricting access of the unauthenticated
	emergency caller to the LoST server and the PSAP URI, traffic can be		emergency caller to the LoST server and the PSAP URI, traffic can be
	restricted only to emergency calls. This can be accomplished with		restricted only to emergency calls. This can be accomplished with
	traffic separation. The details, however, e.g. for using filtering,		traffic separation. The details, however, e.g. for using filtering,
	depend on the deployed ISP architecture and are beyond the scope of		depend on the deployed ISP architecture and are beyond the scope of
	this document.		this document.
	We only illustrate a possible model. If the ISP runs its own LoST		We only illustrate a possible model. If the ISP runs its own
	server, it would maintain an access control list including all IP		(caching) LoST server, the ISP would maintain an access control list
	addresses contained in responses returned by the LoST server, as well		populated with IP-address information obtained from LoST responses
	as the LoST server itself. (It may need to translate the domain		(in the mappings). These URIs would either be URIs for contacting
	names returned to IP addresses and hope that the resolution captures		further LoST servers or PSAP URIs. It may be necessary to translate
	all possible DNS responses.) Since the media destination addresses		domain names returned in LoST responses to IP addresses. Since the
	are not predictable, the ISP also has to provide a SIP outbound proxy		media destination addresses are not predictable, the ISP also has to
	so that it can determine the media addresses and add those to the		provide a SIP outbound proxy so that it can determine the media
	filter list.		addresses and add those to the filter list.
	For the ZBP case the additional aspect of fraud has to be considered.		For the ZBP case the additional aspect of fraud has to be considered.
	Unless the emergency call traverses a PSTN gateway or the ASP charges		Unless the emergency call traverses a PSTN gateway or the ASP charges
	for IP-to-IP calls, there is little potential for fraud. If the ASP		for IP-to-IP calls, there is little potential for fraud. If the ASP
	also operates the LoST server, the outbound proxy MAY restrict		also operates the LoST server, the outbound proxy MAY restrict
	outbound calls to the SIP URIs returned by the LoST server. It is		outbound calls to the SIP URIs returned by the LoST server. It is
	NOT RECOMMENDED to rely on a fixed list of SIP URIs, as that list may		NOT RECOMMENDED to rely on a fixed list of SIP URIs, as that list may
	change.		change.
	Finally, a number of security vulnerabilities discussed in [RFC6280]		RFC 6280 [RFC6280] discusses security vulnerabilities that are caused
	around faked location information are less problematic in the context		by an adversary faking location information and thereby lying about
	of unauthenticated emergency since location information does not need		the actual location of the emergency caller. These threats may be
	to be provided by the end host itself or it can be verified to fall		less problematic in the context of unauthenticated emergency when
	within a specific geographical area.		location information can be verified by the ISP to fall within a
			specific geographical area.
	8. Acknowledgments		8. Acknowledgments
	Parts of this document are derived from [RFC6881]. Participants of		Parts of this document are derived from [RFC6881]. Participants of
	the 2nd and 3rd SDO Emergency Services Workshop provided helpful		the 2nd and 3rd SDO Emergency Services Workshop provided helpful
	input.		input.
	We would like to thank Richard Barnes, Brian Rosen, James Polk, Marc		We would like to thank Richard Barnes, Brian Rosen, James Polk, Marc
	Linsner, and Martin Thomson for their feedback at the IETF#80 ECRIT		Linsner, and Martin Thomson for their feedback at the IETF#80 ECRIT
	meeting.		meeting.
	skipping to change at page 22, line 27 ¶		skipping to change at page 22, line 45 ¶
	3748, June 2004.		3748, June 2004.
	[RFC5216] Simon, D., Aboba, B., and R. Hurst, "The EAP-TLS		[RFC5216] Simon, D., Aboba, B., and R. Hurst, "The EAP-TLS
	Authentication Protocol", RFC 5216, March 2008.		Authentication Protocol", RFC 5216, March 2008.
	[RFC6280] Barnes, R., Lepinski, M., Cooper, A., Morris, J.,		[RFC6280] Barnes, R., Lepinski, M., Cooper, A., Morris, J.,
	Tschofenig, H., and H. Schulzrinne, "An Architecture for		Tschofenig, H., and H. Schulzrinne, "An Architecture for
	Location and Location Privacy in Internet Applications",		Location and Location Privacy in Internet Applications",
	BCP 160, RFC 6280, July 2011.		BCP 160, RFC 6280, July 2011.
	[esw07] , "3rd SDO Emergency Services Workshop,		[esw07] "3rd SDO Emergency Services Workshop,
	http://www.emergency-services-coordination.info/2007Nov/",		http://www.emergency-services-coordination.info/2007Nov/",
	October 30th - November 1st 2007.		October 30th - November 1st 2007.
	[nwgstg3] , "WiMAX Forum WMF-T33-001-R015V01, WiMAX Network		[nwgstg3] "WiMAX Forum WMF-T33-001-R015V01, WiMAX Network
	Architecture Stage-3		Architecture Stage-3
	http://www.wimaxforum.org/sites/wimaxforum.org/files/		http://www.wimaxforum.org/sites/wimaxforum.org/files/
	technical_document/2009/09/DRAFT-T33-001-R015v01		technical_document/2009/09/DRAFT-T33-001-R015v01-
	-O_Network-Stage3-Base.pdf", September 2009.		O_Network-Stage3-Base.pdf", September 2009.
	Authors' Addresses		Authors' Addresses
	Henning Schulzrinne		Henning Schulzrinne
	Columbia University		Columbia University
	Department of Computer Science		Department of Computer Science
	450 Computer Science Building		450 Computer Science Building
	New York, NY 10027		New York, NY 10027
	US		US
	skipping to change at page 23, line 4 ¶		skipping to change at page 23, line 23 ¶
	Henning Schulzrinne		Henning Schulzrinne
	Columbia University		Columbia University
	Department of Computer Science		Department of Computer Science
	450 Computer Science Building		450 Computer Science Building
	New York, NY 10027		New York, NY 10027
	US		US
	Phone: +1 212 939 7004		Phone: +1 212 939 7004
	Email: hgs+ecrit@cs.columbia.edu		Email: hgs+ecrit@cs.columbia.edu
	URI: http://www.cs.columbia.edu		URI: http://www.cs.columbia.edu
	Stephen McCann		Stephen McCann
	Research in Motion UK Ltd		Research in Motion UK Ltd
	200 Bath Road		200 Bath Road
	Slough, Berks SL1 3XE		Slough, Berks SL1 3XE
	UK		UK
	Phone: +44 1753 667099		Phone: +44 1753 667099
	Email: smccann@rim.com		Email: smccann@rim.com
	URI: http://www.rim.com		URI: http://www.rim.com
	Gabor Bajko		Gabor Bajko
	Nokia		Nokia
	Email: Gabor.Bajko@nokia.com		Email: Gabor.Bajko@nokia.com
	Hannes Tschofenig		Hannes Tschofenig
	Nokia Solutions and Networks		Hall in Tirol 6060
	Linnoitustie 6		Austria
	Espoo 02600
	Finland
	Phone: +358 (50) 4871445
	Email: Hannes.Tschofenig@gmx.net		Email: Hannes.Tschofenig@gmx.net
	URI: http://www.tschofenig.priv.at		URI: http://www.tschofenig.priv.at
	Dirk Kroeselberg		Dirk Kroeselberg
	Siemens		Siemens
	Germany		Germany
	Email: dirk.kroeselberg@siemens.com		Email: dirk.kroeselberg@siemens.com
End of changes. 35 change blocks.
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