draft-ietf-ecrit-unauthenticated-access-01.txt		draft-ietf-ecrit-unauthenticated-access-02.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 28, 2011 Research in Motion UK Ltd		Expires: September 30, 2011 Research in Motion UK Ltd
	G. Bajko		G. Bajko
	Nokia		Nokia
	H. Tschofenig		H. Tschofenig
	D. Kroeselberg
	Nokia Siemens Networks		Nokia Siemens Networks
	October 25, 2010		D. Kroeselberg
			Siemens
			March 29, 2011
	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-01.txt		draft-ietf-ecrit-unauthenticated-access-02.txt
	Abstract		Abstract
	The IETF emergency services architecture assumes that the calling		The IETF emergency services architecture assumes that the calling
	device has acquired rights to use the access network or that no		device has acquired rights to use the access network or that no
	authentication is required for the access network, such as for public		authentication is required for the access network, such as for public
	wireless access points. Subsequent protocol interactions, such as		wireless access points. Subsequent protocol interactions, such as
	obtaining location information, learning the address of the Public		obtaining location information, learning the address of the Public
	Safety Answering Point (PSAP) and the emergency call itself are		Safety Answering Point (PSAP) and the emergency call itself are
	largely decoupled from the underlying network access procedures.		largely decoupled from the underlying network access procedures.
	skipping to change at page 2, line 6		skipping to change at page 2, line 7
	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
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on April 28, 2011.		This Internet-Draft will expire on September 30, 2011.
	Copyright Notice		Copyright Notice
	Copyright (c) 2010 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
	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
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	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 . . . . . . . . . . . . . . . . . . . . . . . . . 4		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7
	3. Use Case Categories . . . . . . . . . . . . . . . . . . . . . 6		3. Use Case Categories . . . . . . . . . . . . . . . . . . . . . 8
	4. ZBP Considerations . . . . . . . . . . . . . . . . . . . . . . 8		4. ZBP Considerations . . . . . . . . . . . . . . . . . . . . . . 10
	5. NASP Considerations . . . . . . . . . . . . . . . . . . . . . 9		5. NASP Considerations . . . . . . . . . . . . . . . . . . . . . 11
	5.1. End Host Profile . . . . . . . . . . . . . . . . . . . . . 11		5.1. End Host Profile . . . . . . . . . . . . . . . . . . . . . 13
	5.1.1. LoST Server Discovery . . . . . . . . . . . . . . . . 11		5.1.1. LoST Server Discovery . . . . . . . . . . . . . . . . 13
	5.1.2. ESRP Discovery . . . . . . . . . . . . . . . . . . . . 11		5.1.2. ESRP Discovery . . . . . . . . . . . . . . . . . . . . 13
	5.1.3. Location Determination and Location Configuration . . 11		5.1.3. Location Determination and Location Configuration . . 13
	5.1.4. Emergency Call Identification . . . . . . . . . . . . 11		5.1.4. Emergency Call Identification . . . . . . . . . . . . 13
	5.1.5. SIP Emergency Call Signaling . . . . . . . . . . . . . 12		5.1.5. SIP Emergency Call Signaling . . . . . . . . . . . . . 13
	5.1.6. Media . . . . . . . . . . . . . . . . . . . . . . . . 12		5.1.6. Media . . . . . . . . . . . . . . . . . . . . . . . . 14
	5.1.7. Testing . . . . . . . . . . . . . . . . . . . . . . . 12		5.1.7. Testing . . . . . . . . . . . . . . . . . . . . . . . 14
	5.2. IAP/ISP Profile . . . . . . . . . . . . . . . . . . . . . 12		5.2. IAP/ISP Profile . . . . . . . . . . . . . . . . . . . . . 14
	5.2.1. ESRP Discovery . . . . . . . . . . . . . . . . . . . . 12		5.2.1. ESRP Discovery . . . . . . . . . . . . . . . . . . . . 14
	5.2.2. Location Determination and Location Configuration . . 12		5.2.2. Location Determination and Location Configuration . . 14
	5.3. ESRP Profile . . . . . . . . . . . . . . . . . . . . . . . 13		5.3. ESRP Profile . . . . . . . . . . . . . . . . . . . . . . . 14
	5.3.1. Emergency Call Routing . . . . . . . . . . . . . . . . 13		5.3.1. Emergency Call Routing . . . . . . . . . . . . . . . . 14
	5.3.2. Emergency Call Identification . . . . . . . . . . . . 13		5.3.2. Emergency Call Identification . . . . . . . . . . . . 14
	5.3.3. SIP Emergency Call Signaling . . . . . . . . . . . . . 13		5.3.3. SIP Emergency Call Signaling . . . . . . . . . . . . . 15
	5.3.4. Location Retrieval . . . . . . . . . . . . . . . . . . 13		6. Lower Layer Considerations for NAA Case . . . . . . . . . . . 16
	6. Lower Layer Considerations for NAA Case . . . . . . . . . . . 14		6.1. Link Layer Emergency Indication . . . . . . . . . . . . . 16
	6.1. Link Layer Emergency Indication . . . . . . . . . . . . . 14		6.2. Securing Network Attachment in NAA Cases . . . . . . . . . 17
	6.2. Higher-Layer Emergency Indication . . . . . . . . . . . . 15		7. Security Considerations . . . . . . . . . . . . . . . . . . . 20
	6.3. Securing Network Attachment in NAA Cases . . . . . . . . . 17		8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 21
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 18		9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
	8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19		10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
	9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19		10.1. Normative References . . . . . . . . . . . . . . . . . . . 23
	10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19		10.2. Informative References . . . . . . . . . . . . . . . . . . 23
	10.1. Normative References . . . . . . . . . . . . . . . . . . . 19		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26
	10.2. Informative References . . . . . . . . . . . . . . . . . . 20
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22
	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, which are
	skipping to change at page 6, line 40		skipping to change at page 8, line 23
	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
	get access to the network.		get access to the network.
	Pre-Emergency Service Configuration: When the link layer network		Pre-Emergency Service Configuration: When the link layer network
	attachment procedure is completed the end host learns basic		attachment procedure is completed the end host learns basic
	configuration information using DHCP from the ISP, including the		configuration information using DHCP from the ISP. The end host
	address of the LoST server. The end host uses a Location		uses a Location Configuration Protocol (LCP) to retrieve location
	Configuration Protocol (LCP) to retrieve location information.		information. Subsequently, the LoST protocol [RFC5222] is used to
	Subsequently, the LoST protocol [RFC5222] is used to learn the		learn the relevant emergency numbers, and to obtain the PSAP URI
	relevant emergency numbers, and to obtain the PSAP URI applicable		applicable for that location.
	for that location.
	Emergency Call: In case of need for help, a user dials an emergency		Emergency Call: In case of need for help, a user dials an emergency
	number and the SIP UA initiates the emergency call procedures by		number and the SIP UA initiates the emergency call procedures by
	communicating with the PSAP.		communicating with the PSAP.
	Figure 1 compiles the basic logic taking place during network entry		Figure 1 compiles the basic logic taking place during network entry
	for requesting an emergency service and shows the interrelation		for requesting an emergency service and shows the interrelation
	between the three conditions described in the above section.		between the three conditions described in the above section.
	+-----Y		+-----Y
	skipping to change at page 9, line 15		skipping to change at page 11, line 12
	ASP policy and deployment, and is therefore beyond the scope of this		ASP policy and deployment, and is therefore beyond the scope of this
	document.		document.
	5. NASP Considerations		5. NASP Considerations
	To start the description we consider the sequence of steps that are		To start the description we consider the sequence of steps that are
	executed in an emergency call based on Figure 2.		executed in an emergency call based on Figure 2.
	o As an initial step the devices attaches to the network as shown in		o As an initial step the devices attaches to the network as shown in
	step (1). This step is outside the scope of this section.		step (1). This step is outside the scope of this section.
	o When the link layer network attachment procedure is completed the		o When the link layer network attachment procedure is completed the
	end host learns basic configuration information using DHCP from		end host learns basic configuration information using DHCP from
	the ISP, including the address of the ESRP, as shown in step (2).		the ISP, as shown in step (2).
	o When the IP address configuration is completed then the SIP UA
	initiates a SIP INVITE towards the indicated ESRP, as shown in		o When the IP address configuration is completed then the end host
	(3). The INVITE message contains all the necessary parameters		starts an interaction with the discovered Location Configuration
	required by Section 5.1.5.		Server at the ISP, as shown in step (3). The ISP may in certain
			deployments need to interact with the IAP. This protocol exchange
			is shown in step (4).
			o Once location information is obtained the end host triggers the
			LoST protocol to obtain the address of the ESRP/PSAP. This step
			is shown in (5).
			o In step (6), the SIP UA initiates a SIP INVITE towards the
			indicated ESRP. The INVITE message contains all the necessary
			parameters required by Section 5.1.5.
	o The ESRP receives the INVITE and processes it according to the		o The ESRP receives the INVITE and processes it according to the
	description in Section 5.3.3. The location of the end host may		description in Section 5.3.3.
	need to be determined using a protocol interaction shown in (4).
	o Potentially, an interaction between the LCS of the ISP and the LCS		o The ESRP routes the call to the PSAP, as shown in (8), potentially
	of the IAP may be necessary, see (5).		interacting with a LoST server first to determine the route.
	o Finally, the correct PSAP for the location of the end host has to
	be evaluated, see (6).
	o The ESRP routes the call to the PSAP, as shown in (7).
	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 emergency caller.		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 2.		the PSAP and SIP UA are not shown in Figure 2.
	Two important aspects are worth to highlight:		+-------+
			| PSAP |
	o The IAP/ISP needs to understand the concept of emergency calls or		| |
	other emergency applicationsand the SIP profile described in this		+-------+
	document. No other VoIP protocol profile, such as XMPP, Skype,		^
	etc., are supported for emergency calls in this particular		| (8)
	architecture. Other profiles may be added in the future, but the		|
	deployment effort is enormous since they have to be universally		+----------+(7) +----------+
	deployed.		| LoST |<-->| ESRP |
	o The end host has no obligation to determine location information.		| Server | | |
	It may attach location information if it has location available		+----------+ +----------+
	(e.g., from a GPS receiver).		^ ^
			+----------------+----------------|--------------+
	Figure 2 shows that the ISP needs to deploy SIP-based emergency		| ISP | | |
	services functionality. It is important to note that the ISP itself		|+----------+ | | +----------+|
	may outsource the functionality by simply providing access to them		|| LCS-ISP | (3)| | | DHCP ||
	(e.g., it puts the IP address of an ESRP or a LoST server into an		|| |<-+ | | | Server ||
	allow-list). For editorial reasons this outsourcing is not shown.		|+----------+ | | | +----------+|
			+-------^------+-+----------------|-----------^--+
	+-------+ +-------+		+-------|------+-+----------------|-----------|--+
	| PSAP | (7) | ESRP |		| IAP | (4) | |(5) | | |
	| |<----->| |		| V | | | | |
	+-------+ +-------+		|+----------+ | | | | |
	^		|| LCS-IAP | | | +--------+ | | |
	| (7)		|| | | | | Link | |(6) | |
	v		|+----------+ | | | Layer | | | |
	+----------+ (6) +----------+		| | | | Device | | (2)| |
	| Mapping |<----->| ESRP |		| | | +--------+ | | |
	| Database | | |<-+		| | | ^ | | |
	+----------+ +----------+ |		| | | | | | |
	^ |		+--------------+-|-------|--------|-----------|--+
	+------------------------|--------|--------------+		| | | | |
	| ISP | | |		| | (1)| | |
	|+----------+ | | +----------+|		| | | | |
	|| LCS-ISP | | | | DHCP ||		| | | +----+ |
	|| |<-----------+ | | Server ||		| | v | |
	|+----------+ (4) | +----------+|		| | +----------+ |
	+-------^-------------------------|-----------^--+		| +->| End |<-------------+
	+-------|-------------------------|-----------|--+		+___>| Host |
	| IAP | (5) | | |		+----------+
	| V | | |
	|+----------+ | | |
	|| LCS-IAP | +--------+ | | |
	|| | | Link | |(3) | |
	|+----------+ | Layer | | | |
	| | Device | | (2)| |
	| +--------+ | | |
	| ^ | | |
	| | | | |
	+------------------------|--------|-----------|--+
	| | |
	(1)| | |
	| | |
	| +----+ |
	v v |
	+----------+ |
	| End |<-------------+
	| Host |
	+----------+
	Figure 2: Architectural Overview		Figure 2: Architectural Overview
	Note: Figure 2 does not indicate who runs the ESRP or the mapping		Note: Figure 2 does not indicate who operates the ESRP and the LoST
	database. There are different options available.		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
	The end host MAY attempt to use [RFC5222] to discover a LoST server.		The end host MUST discover a LoST server [RFC5222] using DHCP
	If that attempt fails, the end host SHOULD attempt to discover the		[RFC5223].
	address of an ESRP.
	5.1.2. ESRP Discovery		5.1.2. ESRP Discovery
	The end host only needs an ESRP when location configuration or LoST		The end host MUST discover the ESRP using the LoST protocol
	server discovery fails. If that is the case, then the end host MUST		[RFC5222].
	use the "Dynamic Host Configuration Protocol (DHCP-for-IPv4) Option
	for Session Initiation Protocol (SIP) Servers" [RFC3361] (for IPv6)
	and / or the "Dynamic Host Configuration Protocol (DHCPv6) Options
	for Session Initiation Protocol (SIP) Servers" [RFC3319] to discover
	the address of an ESRP. This SIP proxy located in the ISP network
	will be used as the ESRP for routing emergency calls. There is no
	need to discovery a separate SIP proxy with specific emergency call
	functionality since the internal procedure for emergency call
	processing is subject of ISP internal operation.
	5.1.3. Location Determination and Location Configuration		5.1.3. Location Determination and Location Configuration
	The end host SHOULD attempt to use the supported LCPs to configure		The end host MUST support location acquisition and the LCPs described
	its location. If no LCP is supported in the end host or the location		in Section 6.5 of [I-D.ietf-ecrit-phonebcp]. The description in
	configuration is not successful, then the end host MUST attempt to		Section 6.5 and 6.6 of [I-D.ietf-ecrit-phonebcp] regarding the
	discover an ESRP, which would assist the end host in providing the		interaction between the device and the LIS applies to this document.
	location to the PSAP.
	The SIP UA in the end host MUST attach available location information		The SIP UA in the end host MUST attach available location information
	in a PIDF-LO [RFC4119] when making an emergency call. When		in a PIDF-LO [RFC4119] when making an emergency call. When
	constructing the PIDF-LO the guidelines in PIDF-LO profile [RFC5491]		constructing the PIDF-LO the guidelines in PIDF-LO profile [RFC5491]
	MUST be followed. For civic location information the format defined		MUST be followed. For civic location information the format defined
	in [RFC5139] MUST be supported.		in [RFC5139] MUST be supported.
	5.1.4. Emergency Call Identification		5.1.4. Emergency Call Identification
	To determine which calls are emergency calls, some entity needs to		To determine which calls are emergency calls, some entity needs to
	map a user entered dialstring into this URN scheme. A user may		map a user entered dialstring into this URN scheme. A user may
	"dial" 1-1-2, but the call would be sent to urn:service:sos. This		"dial" 1-1-2, but the call would be sent to urn:service:sos. This
	mapping SHOULD be performed at the endpoint device.		mapping SHOULD be performed at the endpoint device.
	End hosts MUST use the Service URN mechanism [RFC5031] to mark calls		End hosts MUST use the Service URN mechanism [RFC5031] to mark calls
	as emergency calls for their home emergency dial string (if known).		as emergency calls for their home emergency dial string.
	For visited emergency dial string the translation into the Service
	URN mechanism is not mandatory since the ESRP in the ISPs network
	knows the visited emergency dial strings.
	5.1.5. SIP Emergency Call Signaling		5.1.5. SIP Emergency Call Signaling
	SIP signaling capabilities [RFC3261] are mandated for end hosts.		SIP signaling capabilities [RFC3261] are mandated for end hosts.
	The initial SIP signaling method is an INVITE. The SIP INVITE		The initial SIP signaling method is an INVITE. The SIP INVITE
	request MUST be constructed according to the requirements in Section		request MUST be constructed according to the requirements in Section
	9.2 [I-D.ietf-ecrit-phonebcp].		9.2 [I-D.ietf-ecrit-phonebcp].
	Regarding callback behavior SIP UAs MUST have a globally routable URI		Regarding callback behavior SIP UAs SHOULD place a globally routable
	in a Contact: header.		URI in a Contact: header.
	5.1.6. Media		5.1.6. Media
	End points MUST comply with the media requirements for end points		End points MUST comply with the media requirements for end points
	placing an emergency call found in Section 14 of		placing an emergency call found in Section 14 of
	[I-D.ietf-ecrit-phonebcp].		[I-D.ietf-ecrit-phonebcp].
	5.1.7. Testing		5.1.7. Testing
	The description in Section 15 of [I-D.ietf-ecrit-phonebcp] is fully		The description in Section 15 of [I-D.ietf-ecrit-phonebcp] is fully
	applicable to this document.		applicable to this document.
	5.2. IAP/ISP Profile		5.2. IAP/ISP Profile
	5.2.1. ESRP Discovery		5.2.1. ESRP Discovery
	An ISP hosting an ESRP MUST implement the server side part of		An ISP MUST provision a DHCP server with information about LoST
	"Dynamic Host Configuration Protocol (DHCP-for-IPv4) Option for		servers [RFC5223]. An ISP operator may choose to deploy a LoST
	Session Initiation Protocol (SIP) Servers" [RFC3361] (for IPv4) and /		server or to outsource it to other parties.
	or the "Dynamic Host Configuration Protocol (DHCPv6) Options for
	Session Initiation Protocol (SIP) Servers" [RFC3319].
	5.2.2. Location Determination and Location Configuration		5.2.2. Location Determination and Location Configuration
	When receiving an INVITE message the following steps are done:		The ISP is responsible for location determination and exposes this
	1. If the INVITE message does not include location information the		information to the end points via location configuration protocols.
	ESRP-registrar MUST use HELD identity		The considerations described in [I-D.ietf-ecrit-location-hiding-req]
	[I-D.ietf-geopriv-held-identity-extensions] to obtain the		are applicable to this document.
	location of the device as both a location value and reference.
	In order to contact the LIS the ESRP-registrar SHOULD determine		The ISP MUST support one of the LCPs described in Section 6.5 of
	the LIS address using the mechanism described in		[I-D.ietf-ecrit-phonebcp]. The description in Section 6.5 and 6.6 of
	[I-D.thomson-geopriv-res-gw-lis-discovery]. The ESRP-registrar		[I-D.ietf-ecrit-phonebcp] regarding the interaction between the end
	MAY use other methods for LIS determination where available.		device and the LIS applies to this document.
	2. If the INVITE message contains a location URI then the ESRP-
	registrar MUST dereference it so that it has a location available		The interaction between the LIS at the ISP and the IAB is often
	to route the impending emergency call. The ESRP-registrar MAY		priorietary but the description in
	validate the LIS address in the location URI with that of the LIS		[I-D.winterbottom-geopriv-lis2lis-req] may be relevant to the reader.
	serving the network from which the INVITE message originated.
	3. The INVITE message contains location information by value. Any
	actions performed by the ESRP-registrar to valid this information
	are specific to the jurisdiction in which the ESRP operates and
	are out of the scope of this document.
	5.3. ESRP Profile		5.3. ESRP Profile
	5.3.1. Emergency Call Routing		5.3.1. Emergency Call Routing
	The ESRP must route the emergency call to the PSAP responsible for		The ESRP continues to route the emergency call to the PSAP
	the physical location of the end host. However, a standardized		responsible for the physical location of the end host. This may
	approach for determining the correct PSAP based on a given location		require further interactions with LoST servers but depends on the
	is useful but not mandatory.		specific deployment.
	For cases where a standardized protocol is used LoST [RFC5222] is a
	suitable mechanism.
	5.3.2. Emergency Call Identification		5.3.2. Emergency Call Identification
	The ESRP MUST understand the Service URN mechanism [RFC5031] (i.e.,		The ESRP MUST understand the Service URN mechanism [RFC5031] (i.e.,
	the 'urn:service:sos' tree) and additionally the national emergency		the 'urn:service:sos' tree).
	dial strings. The ESRP SHOULD perform a mapping of national
	emergency dial strings to Service URNs to simplify processing at
	PSAPs.
	5.3.3. SIP Emergency Call Signaling		5.3.3. SIP Emergency Call Signaling
	SIP signaling capabilities [RFC3261] are mandated for the ESRP. The		SIP signaling capabilities [RFC3261] are mandated 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. Furthermore, the ESRP MUST be able to add a reference		Section 5.1.5.
	to location information, as described in SIP Location Conveyance
	[I-D.ietf-sipcore-location-conveyance], before forwarding the call to
	the PSAP. The ISP MUST be prepared to receive incoming dereferencing
	requests to resolve the reference to the location information.
	5.3.4. Location Retrieval
	The ESRP acts a location recipient and the usage of HELD [RFC5985]
	with the identity extensions
	[I-D.ietf-geopriv-held-identity-extensions] may be a possible choice.
	The ESRP would thereby act as a HELD client and the corresponding LIS
	at the ISP as the HELD server.
	The ESRP needs to obtain enough information to route the call. The
	ESRP itself, however, does not necessarily need to process location
	information obtained via HELD since it may be used as input to LoST
	to obtain the PSAP URI.
	6. Lower Layer Considerations for NAA Case		6. Lower Layer Considerations for NAA Case
	Some radio networks have added support for unauthenticated emergency		Some radio 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.
	This section discusses different methods to indicate an emergency		This section discusses different methods to indicate an emergency
	skipping to change at page 14, line 36		skipping to change at page 16, line 31
	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. signalling allows an IEEE 802.1X to occur without		wireless link. In IEEE 802.11 WLAN, an emergency support
	exchanging cryptogrpahic keys.		indicator allows the STA to download before association an NAI
			which it can use to request server side authentication only for an
			802.1x network.
	Higher-layer emergency indication: Typically emergency indication in		Higher-layer emergency indication: Typically emergency indication in
	access authentication. The emergency caller's end host provides		access authentication. The emergency caller's end host provides
	an indication as part of the access authentication exchanges. EAP		an indication as part of the access authentication exchanges. EAP
	based authentication is of particular relevance here. [nwgstg3].		based authentication is of particular relevance here. Examples
			are the EAP NAI decoration used in WiMAX networks and modification
			of the authentication exchange in IEEE 802.11. [nwgstg3].
	6.1. Link Layer Emergency Indication		6.1. Link Layer Emergency Indication
	In general, link layer emergency indications provide good integration		In general, link layer emergency indications provide good integration
	into the actual network access procedure regarding the enabling of		into the actual network access procedure regarding the enabling of
	means to recognize and prioritize an emergency service request from		means to recognize and prioritize an emergency service request from
	an end host at a very early stage of the network attachment		an end host at a very early stage of the network attachment
	procedure. However, support in end hosts for such methods cannot be		procedure. However, support in end hosts for such methods cannot be
	considered to be commonly available.		considered to be commonly available.
	skipping to change at page 15, line 8		skipping to change at page 17, line 7
	In general, link layer emergency indications provide good integration		In general, link layer emergency indications provide good integration
	into the actual network access procedure regarding the enabling of		into the actual network access procedure regarding the enabling of
	means to recognize and prioritize an emergency service request from		means to recognize and prioritize an emergency service request from
	an end host at a very early stage of the network attachment		an end host at a very early stage of the network attachment
	procedure. However, support in end hosts for such methods cannot be		procedure. However, support in end hosts for such methods cannot be
	considered to be commonly available.		considered to be commonly available.
	No general recommendations are given in the scope of this memo due to		No general recommendations are given in the scope of this memo due to
	the following reasons:		the following reasons:
	o Dependency on the specific access technology.		o Dependency on the specific access technology.
	o Dependency on the specific access network architecture. Access		o Dependency on the specific access network architecture. Access
	authorization and policy decisions typically happen at a different		authorization and policy decisions typically happen at a different
	layers of the protocol stack and in different entities than those		layers of the protocol stack and in different entities than those
	terminating the link-layer signaling. As a result, link layer		terminating the link-layer signaling. As a result, link layer
	indications need to be distributed and translated between the		indications need to be distributed and translated between the
	different involved protocol layers and entities. Appropriate		different involved protocol layers and entities. Appropriate
	methods are specific to the actual architecture of the IAP/ISP		methods are specific to the actual architecture of the IAP/ISP
	network.		network.
	6.2. Higher-Layer Emergency Indication		o An advantage of combining emergency indications with the actual
			network attachment procedure performing authentication and
	This section focuses on emergency indications based on authentication		authorization is the fact that the emergency indication can
	and authorization in EAP-based network access.		directly be taken into account in the authentication and
			authorization server that owns the policy for granting access to
	An advantage of combining emergency indications with the actual		the network resources. As a result, there is no direct dependency
	network attachment procedure performing authentication and		on the access network architecture that otherwise would need to
	authorization is the fact that the emergency indication can directly		take care of merging link-layer indications into the AA and policy
	be taken into account in the authentication and authorization server		decision process.
	that owns the policy for granting access to the network resources.
	As a result, there is no direct dependency on the access network
	architecture that otherwise would need to take care of merging link-
	layer indications into the AA and policy decision process.
	EAP signaling happens at a relatively early stage of network
	attachment, so it is likely to match most requirements for
	prioritization of emergency signaling. However, it does not cover
	early stages of link layer activity in the network attachment
	process. Possible conflicts may arise e.g. in case of MAC-based
	filtering in entities terminating the link-layer signaling in the
	network (like a base station). In normal operation, EAP related
	information will only be recognized in the NAS. Any entity residing
	between end host and NAS should not be expected to understand/parse
	EAP messages.
	The following potential methods to provide emergency indications in
	combination with EAP-based network attachment, are recognized:
	1. NAI-based emergency indication:
	An emergency indication can be given by forming a specific NAI
	that is used as the identity in EAP based authentication for
	network entry. Methods include:
	2.
	1.a) NAI Decoration:
	NAI decoration is commonly used in routing EAP responses
	within the IAP/ISP AAA infrastructure. Additional decoration
	can be used to add an indication that the network attachment
	attempt is meant for accessing emergency services. Potential
	advantages of such approach include that it requires only
	minimal realization effort compared to link-layer indications
	with good integration into the authentication and
	authorization procedures. The same procedure can be used for
	all NAA cases (both unauthenticated and unauthorized) as well
	as for normal attachment with a valid subscription. A
	potential disadvantage is that such EAP decoration is not
	globally defined across all different access technologies.
	1.b) Emergency NAI:
	The NAI comes with a realm or username part indicating
	emergency (e.g. 'emergency@emergency.com'). An advantage of
	this method for NAA cases is that no new requirements are put
	on the involved signaling procedures. Only the identity used
	for network entry is impacted. Potential disadvantages
	include that different methods to indicate emergency for NAA
	cases and standard emergency network attachments may be
	required. Also, modifying the NAI itself (the username@realm
	part) may conflict with network selection and network entry
	procedures, depending on the actual access network.
	3. Emergency EAP method
	An emergency indication can be given by using a dedicated EAP
	method that is reserved for emergency network attachment only.
	2.a) Existing EAP method with New Method Type:
	An existing EAP method may be used. EAP methods themselves
	typically do not support emergency indication. One option
	would be to pick a common EAP method like EAP-TLS and allocate
	a new method type for the same method that is exclusively
	reserved to emergency use. Such EAP method should be chosen
	in a way that the same method can support NAA cases as well as
	standard emergency network attachment.
	2.b) Existing EAP Method:
	Same as 2a), but without assigning a new EAP method type for
	emergency. In this case some implicit indication must be
	used. For example, in cases where EAP-TLS is used in network
	attachment in combination with client certificates, the
	absence of a client certificate could be interpreted by the
	network as a request for emergency network attachment.
	2.c) Emergency EAP Method:		o EAP signaling happens at a relatively early stage of network
			attachment, so it is likely to match most requirements for
			prioritization of emergency signaling. However, it does not cover
			early stages of link layer activity in the network attachment
			process. Possible conflicts may arise e.g. in case of MAC-based
			filtering in entities terminating the link-layer signaling in the
			network (like a base station). In normal operation, EAP related
			information will only be recognized in the NAS. Any entity
			residing between end host and NAS should not be expected to
			understand/parse EAP messages.
	A new EAP method could be defined that is specifically		o An emergency indication can be given by forming a specific NAI
	designed for emergency network entry in NAA cases. Most		that is used as the identity in EAP based authentication for
	likely, such EAP method would not be usable for standard		network entry.
	emergency network attachment with an existing subscription.
	Such dedicated emergency EAP method should be key-generating
	in compliance with RFC3748 to enable the regular air interface
	security methods even in unauthenticated operation.
	6.3. Securing Network Attachment in NAA Cases		6.2. Securing Network Attachment in NAA Cases
	For network attachment in NAA cases, it may make sense to secure the		For network attachment in NAA cases, it may make sense to secure the
	link-layer connection between the device and the IAP/ISP. This		link-layer connection between the device and the IAP/ISP. This
	especially holds for wireless access with examples being based		especially holds for wireless access with examples being IEEE 802.11
	access. The latter even mandates secured communication across the		or IEEE 802.16 based access. The latter even mandates secured
	wireless link for all IAP/ISP networks based on [nwgstg3].		communication across the wireless link for all IAP/ISP networks based
			on [nwgstg3].
	Therefore, for network attachment that is by default based on EAP		Therefore, for network attachment that is by default based on EAP
	authentication it is desirable also for NAA network attachment to use		authentication it is desirable also for NAA network attachment to use
	a key-generating EAP method (that provides an MSK key to the		a key-generating EAP method (that provides an MSK key to the
	authenticator to bootstrap further key derivation for protecting the		authenticator to bootstrap further key derivation for protecting the
	wireless link).		wireless link).
	The following approaches to match the above can be identified:		The following approaches to match the above can be identified:
	1) Server-only Authentication:		1) Server-only Authentication:
	The device of the emergency service requester performs an EAP		The device of the emergency service requester performs an EAP
	method with the IAP/ISP EAP server that performs server		method with the IAP/ISP EAP server that performs server side
	authentication only. An example for this is EAP-TLS. This		authentication only. An example for this is EAP-TLS. This
	provides a certain level of assurance about the IAP/ISP to the		provides a certain level of assurance about the IAP/ISP to the
	device user. It requires the device to be provisioned with		device user. It requires the device to be provisioned with
	appropriate trusted root certificates to be able to verify the		appropriate trusted root certificates to be able to verify the
	server certificate of the EAP server (unless this step is		server certificate of the EAP server (unless this step is
	explicitly skipped in the device in case of an emergency service		explicitly skipped in the device in case of an emergency service
	request).		request). This method is used to provide access of devices
			without existing credentials to an 802.1x network. The details
			are incorporated into the not yet published 802.11-2011
			specification.
	2) Null Authentication:		2) Null Authentication:
	an EAP method is performed. However, no credentials specific to		In one case (e.g. WiMAX) an EAP method is performed. However, no
	either the server or the device or subscription are used as part		credentials specific to either the server or the device or
	of the authentication exchange. An example for this would be an		subscription are used as part of the authentication exchange. An
	EAP-TLS exchange with using the TLS_DH_anon (anonymous)		example for this would be an EAP-TLS exchange with using the
	ciphersuite. Alternatively, a publicly available static key for		TLS_DH_anon (anonymous) ciphersuite. Alternatively, a publicly
	emergency access could be used. In the latter case, the device		available static key for emergency access could be used. In the
	would need to be provisioned with the appropriate emergency key		latter case, the device would need to be provisioned with the
	for the IAP/ISP in advance.		appropriate emergency key for the IAP/ISP in advance. In another
			case (e.g. IEEE 802.11), no EAP method is used, so that empty
			frames are transported during the over the air IEEE 802.1X
			exchange. In this case the authentication state machine completes
			with no cryptographic keys being exchanged.
	3) Device Authentication:		3) Device Authentication:
	This case extends the server-only authentication case. If the		This case extends the server-only authentication case. If the
	device is configured with a device certificate and the IAP/ISP EAP		device is configured with a device certificate and the IAP/ISP EAP
	server can rely on a trusted root allowing the EAP server to		server can rely on a trusted root allowing the EAP server to
	verify the device certificate, at least the device identity (e.g.,		verify the device certificate, at least the device identity (e.g.,
	the MAC address) can be authenticated by the IAP/ISP in NAA cases.		the MAC address) can be authenticated by the IAP/ISP in NAA cases.
	An example for this are WiMAX devices that are shipped with device		An example for this are WiMAX devices that are shipped with device
	certificates issued under the global WiMAX device public-key		certificates issued under the global WiMAX device public-key
	skipping to change at page 19, line 29		skipping to change at page 21, line 11
	location information does not need to be provided by the end host		location information does not need to be provided by the end host
	itself or it can be verified to fall within a specific geographical		itself or it can be verified to fall within a specific geographical
	area.		area.
	8. Acknowledgments		8. Acknowledgments
	Parts of this document are derived from [I-D.ietf-ecrit-phonebcp].		Parts of this document are derived from [I-D.ietf-ecrit-phonebcp].
	Participants of the 2nd and 3rd SDO Emergency Services Workshop		Participants of the 2nd and 3rd SDO Emergency Services Workshop
	provided helpful input.		provided helpful input.
			We would like to thank Richard Barnes, Brian Rosen, James Polk, Marc
			Linsner, and Martin Thomson for their feedback at the IETF#80 ECRIT
			meeting.
	9. IANA Considerations		9. IANA Considerations
	This document does not require actions by IANA.		This document does not require actions by IANA.
	10. References		10. References
	10.1. Normative References		10.1. Normative References
	[I-D.ietf-sipcore-location-conveyance]
	Polk, J., Rosen, B., and J. Peterson, "Location Conveyance
	for the Session Initiation Protocol",
	draft-ietf-sipcore-location-conveyance-03 (work in
	progress), July 2010.
	[RFC5031] Schulzrinne, H., "A Uniform Resource Name (URN) for		[RFC5031] Schulzrinne, H., "A Uniform Resource Name (URN) for
	Emergency and Other Well-Known Services", RFC 5031,		Emergency and Other Well-Known Services", RFC 5031,
	January 2008.		January 2008.
	[RFC4119] Peterson, J., "A Presence-based GEOPRIV Location Object		[RFC4119] Peterson, J., "A Presence-based GEOPRIV Location Object
	Format", RFC 4119, December 2005.		Format", RFC 4119, December 2005.
	[RFC5491] Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV		[RFC5491] Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV
	Presence Information Data Format Location Object (PIDF-LO)		Presence Information Data Format Location Object (PIDF-LO)
	Usage Clarification, Considerations, and Recommendations",		Usage Clarification, Considerations, and Recommendations",
	RFC 5491, March 2009.		RFC 5491, March 2009.
	[RFC5139] Thomson, M. and J. Winterbottom, "Revised Civic Location		[RFC5139] Thomson, M. and J. Winterbottom, "Revised Civic Location
	Format for Presence Information Data Format Location		Format for Presence Information Data Format Location
	Object (PIDF-LO)", RFC 5139, February 2008.		Object (PIDF-LO)", RFC 5139, February 2008.
	[RFC3361] Schulzrinne, H., "Dynamic Host Configuration Protocol
	(DHCP-for-IPv4) Option for Session Initiation Protocol
	(SIP) Servers", RFC 3361, August 2002.
	[RFC3319] Schulzrinne, H. and B. Volz, "Dynamic Host Configuration
	Protocol (DHCPv6) Options for Session Initiation Protocol
	(SIP) Servers", RFC 3319, July 2003.
	[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.
	Schooler, "SIP: Session Initiation Protocol", RFC 3261,		Schooler, "SIP: Session Initiation Protocol", RFC 3261,
	June 2002.		June 2002.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119, March 1997.		Requirement Levels", BCP 14, RFC 2119, March 1997.
	[I-D.ietf-ecrit-phonebcp]		[I-D.ietf-ecrit-phonebcp]
	Rosen, B. and J. Polk, "Best Current Practice for		Rosen, B. and J. Polk, "Best Current Practice for
	Communications Services in support of Emergency Calling",		Communications Services in support of Emergency Calling",
	draft-ietf-ecrit-phonebcp-15 (work in progress),		draft-ietf-ecrit-phonebcp-17 (work in progress),
	July 2010.		March 2011.
	[RFC5222] Hardie, T., Newton, A., Schulzrinne, H., and H.		[RFC5222] Hardie, T., Newton, A., Schulzrinne, H., and H.
	Tschofenig, "LoST: A Location-to-Service Translation		Tschofenig, "LoST: A Location-to-Service Translation
	Protocol", RFC 5222, August 2008.		Protocol", RFC 5222, August 2008.
	[RFC5223] Schulzrinne, H., Polk, J., and H. Tschofenig, "Discovering		[RFC5223] Schulzrinne, H., Polk, J., and H. Tschofenig, "Discovering
	Location-to-Service Translation (LoST) Servers Using the		Location-to-Service Translation (LoST) Servers Using the
	Dynamic Host Configuration Protocol (DHCP)", RFC 5223,		Dynamic Host Configuration Protocol (DHCP)", RFC 5223,
	August 2008.		August 2008.
	10.2. Informative References		10.2. Informative References
	[RFC5687] Tschofenig, H. and H. Schulzrinne, "GEOPRIV Layer 7		[RFC5687] Tschofenig, H. and H. Schulzrinne, "GEOPRIV Layer 7
	Location Configuration Protocol: Problem Statement and		Location Configuration Protocol: Problem Statement and
	Requirements", RFC 5687, March 2010.		Requirements", RFC 5687, March 2010.
	[I-D.ietf-ecrit-framework]		[I-D.ietf-ecrit-framework]
	Rosen, B., Schulzrinne, H., Polk, J., and A. Newton,		Rosen, B., Schulzrinne, H., Polk, J., and A. Newton,
	"Framework for Emergency Calling using Internet		"Framework for Emergency Calling using Internet
	Multimedia", draft-ietf-ecrit-framework-11 (work in		Multimedia", draft-ietf-ecrit-framework-12 (work in
	progress), July 2010.		progress), October 2010.
	[I-D.thomson-geopriv-res-gw-lis-discovery]		[I-D.ietf-geopriv-res-gw-lis-discovery]
	Thomson, M. and R. Bellis, "Location Information Server		Thomson, M. and R. Bellis, "Location Information Server
	(LIS) Discovery using IP address and Reverse DNS",		(LIS) Discovery using IP address and Reverse DNS",
	draft-thomson-geopriv-res-gw-lis-discovery-04 (work in		draft-ietf-geopriv-res-gw-lis-discovery-01 (work in
	progress), September 2010.		progress), March 2011.
	[RFC5985] Barnes, M., "HTTP-Enabled Location Delivery (HELD)",		[RFC5985] Barnes, M., "HTTP-Enabled Location Delivery (HELD)",
	RFC 5985, September 2010.		RFC 5985, September 2010.
	[RFC5012] Schulzrinne, H. and R. Marshall, "Requirements for		[RFC5012] Schulzrinne, H. and R. Marshall, "Requirements for
	Emergency Context Resolution with Internet Technologies",		Emergency Context Resolution with Internet Technologies",
	RFC 5012, January 2008.		RFC 5012, January 2008.
	[I-D.ietf-geopriv-held-identity-extensions]		[I-D.ietf-ecrit-location-hiding-req]
	Winterbottom, J., Thomson, M., Tschofenig, H., and R.		Schulzrinne, H., Liess, L., Tschofenig, H., Stark, B., and
	Barnes, "Use of Device Identity in HTTP-Enabled Location		A. Kuett, "Location Hiding: Problem Statement and
	Delivery (HELD)",		Requirements", draft-ietf-ecrit-location-hiding-req-04
	draft-ietf-geopriv-held-identity-extensions-05 (work in		(work in progress), February 2010.
	progress), October 2010.
	[I-D.winterbottom-geopriv-lis2lis-req]		[I-D.winterbottom-geopriv-lis2lis-req]
	Winterbottom, J. and S. Norreys, "LIS to LIS Protocol		Winterbottom, J. and S. Norreys, "LIS to LIS Protocol
	Requirements", draft-winterbottom-geopriv-lis2lis-req-01		Requirements", draft-winterbottom-geopriv-lis2lis-req-01
	(work in progress), November 2007.		(work in progress), November 2007.
	[RFC5069] Taylor, T., Tschofenig, H., Schulzrinne, H., and M.		[RFC5069] Taylor, T., Tschofenig, H., Schulzrinne, H., and M.
	Shanmugam, "Security Threats and Requirements for		Shanmugam, "Security Threats and Requirements for
	Emergency Call Marking and Mapping", RFC 5069,		Emergency Call Marking and Mapping", RFC 5069,
	January 2008.		January 2008.
	skipping to change at page 23, line 5		skipping to change at page 27, line 5
	Hannes Tschofenig		Hannes Tschofenig
	Nokia Siemens Networks		Nokia Siemens Networks
	Linnoitustie 6		Linnoitustie 6
	Espoo 02600		Espoo 02600
	Finland		Finland
	Phone: +358 (50) 4871445		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
	Nokia Siemens Networks		Siemens
	St.-Martin-Str. 76
	Munich 81541
	Germany		Germany
	Phone: +49 (89) 515933019		Phone:
	Email: Dirk.Kroeselberg@nsn.com		Email: dirk.kroeselberg@siemens.com
End of changes. 47 change blocks.
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