ECRIT H. Schulzrinne Internet-Draft Columbia University Updates: S. McCann draft-ietf-ecrit-framework; Siemens/Roke Manor Research draft-ietf-ecrit-phonebcp G. Bajko (if approved) Nokia Intended status: Standards Track H. Tschofenig Expires: February 20, 2008 Nokia Siemens Networks August 19, 2007 Extensions to the Emergency Services Architecture for dealing with Unauthenticated and Unauthorized Devices draft-schulzrinne-ecrit-unauthenticated-access-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on February 20, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract The IETF emergency services architecture assumes that access to a network has already happened using the traditional network access Schulzrinne, et al. Expires February 20, 2008 [Page 1]
Internet-Draft Unauthenticated Emergency Service August 2007 authentication procedures or that no authentication for network access is needed (e.g., in case of public hotspots). 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. There are, however, cases where a device is not in possession of credentials for network access, does not have a VoIP provider, or where the credentials are available but became invalid due to various reasons (e.g., credit exhaustion, expired accounts, etc.). This document provides a problem statement, introduces terminology and describes an extension for the base IETF emergency services architecture. Schulzrinne, et al. Expires February 20, 2008 [Page 2]
Internet-Draft Unauthenticated Emergency Service August 2007 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.1. End Host Profile . . . . . . . . . . . . . . . . . . . . . 9 4.1.1. ESRP Discovery . . . . . . . . . . . . . . . . . . . . 9 4.1.2. Location Determination and Location Configuration . . 9 4.1.3. Emergency Call Identification . . . . . . . . . . . . 9 4.1.4. SIP Emergency Call Signaling . . . . . . . . . . . . . 9 4.1.5. Media . . . . . . . . . . . . . . . . . . . . . . . . 10 4.1.6. Testing . . . . . . . . . . . . . . . . . . . . . . . 11 4.2. ISP Profile . . . . . . . . . . . . . . . . . . . . . . . 11 4.2.1. ESRP Discovery . . . . . . . . . . . . . . . . . . . . 11 4.2.2. Location Determination and Location Configuration . . 11 4.2.3. Emergency Call Routing . . . . . . . . . . . . . . . . 11 4.2.4. Emergency Call Identification . . . . . . . . . . . . 12 4.2.5. SIP Emergency Call Signaling . . . . . . . . . . . . . 12 4.2.6. Quality of Service . . . . . . . . . . . . . . . . . . 12 4.3. PSAP Profile . . . . . . . . . . . . . . . . . . . . . . . 12 4.3.1. Location Retrieval . . . . . . . . . . . . . . . . . . 12 4.3.2. Emergency Call Routing . . . . . . . . . . . . . . . . 12 4.3.3. Emergency Call Identification . . . . . . . . . . . . 13 4.3.4. SIP Emergency Call Signaling . . . . . . . . . . . . . 13 4.3.5. Media . . . . . . . . . . . . . . . . . . . . . . . . 13 4.3.6. Testing . . . . . . . . . . . . . . . . . . . . . . . 13 5. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 6. Security Considerations . . . . . . . . . . . . . . . . . . . 14 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14 8. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 14 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 9.1. Normative References . . . . . . . . . . . . . . . . . . . 15 9.2. Informative References . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 Intellectual Property and Copyright Statements . . . . . . . . . . 20 Schulzrinne, et al. Expires February 20, 2008 [Page 3]
Internet-Draft Unauthenticated Emergency Service August 2007 1. Introduction Summoning police, the fire department or an ambulance in emergencies is one of the fundamental and most-valued functions of the telephone. As telephone functionality moves from circuit-switched telephony to Internet telephony, its users rightfully expect that this core functionality will continue to work at least as well as it has for the older technology. New devices and services are being made available that could be used to make a request for help, which are not traditional telephones, and users are increasingly expecting them to be used to place emergency calls. Based on the communication model of the Session Initiation Protocol (SIP) as excerised in the IETF it is not necessary to deploy SIP entities in access networks (or associated to them). Instead, VoIP provider may deploy their SIP entities at any place on the Internet. The IETF emergency services architecture acknowledges this deployment model and even goes a step further by recognizing that there are potentially other, non-SIP VoIP provider, that might want to offer emergency service support to their customers. Hence, the interaction between a SIP User Agent and its VoIP provider does not need to be standarized although [I-D.ietf-ecrit-phonebcp] provides best current practise recommendations regarding the usage of certain features as excerised in the case of SIP. This flexibility has implications for the architecture, as briefly described in [I-D.tschofenig-ecrit-architecture-overview], but allows access networks to be application layer agnostic. Furthermore, since the normal VoIP communication exchanges do not traverse these entities in the access network it is quite likely that interoperability problems will occur especially in an emergency case. There are essentially three environments that need to be considered: 1. The emergency caller does not credentials for access to the network but it still has credentials for his VoIP provider. This is often the case with enterprise networks, home networks, or governmental networks. In other cases the user might be able to obtain such credentials, for example in hotspots found in hotels, at airports, and in many coffee shops. Unfortunately, users have to go through a lengthy procedure (often involving captive portals) to obtain a temporary account in exchange of money. In emergency situations it is certainly not desirable to let the user find their way through a number of webpages and to type-in their credit card details. Schulzrinne, et al. Expires February 20, 2008 [Page 4]
Internet-Draft Unauthenticated Emergency Service August 2007 2. The emergency caller has credentials for network access but does not have credentials for a VoIP provider. This case is rather unlikely. 3. The emergency caller has credentials (for either network access or it's VoIP provider) but they do not provide enough authorization to make a call. This use case essentially refers to lack of authorization. Examples are: Insufficient credits, lack of a roaming agreement (between visited network and home network), disabled account, and other authorization failures. Scenario (1) is the most likely scenario and the main focus of this document. In all these cases it is not possible to place an emergency call as envisioned in the IETF emergerency services architecture, described in [I-D.ietf-ecrit-framework]. Note that at the time of writing there is currently no regulation in place that demands the functionality described in this memo. Since many SDOs have started their work on this subject in a proactive fashion in the anticipation that national regulation in some countries might demand this functionality for a subset of network types. 2. Terminology In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in RFC 2119 [RFC2119]. This document introduces new terminology: Unauthenticated Emergency Service: We use this term in this document to refer to all the cases where the emergency caller does not have credentials or are not authorized to access a network. This also includes cases where a device is not in possession of credentials for network access, does not have a VoIP provider (as it is the case for uninitialized phones), or where the credentials are available but became invalid due to various reasons (e.g., credit exhaustion, expired accounts, etc.). This document reuses terminology from [I-D.ietf-geopriv-l7-lcp-ps] and [I-D.ietf-ecrit-requirements]. Schulzrinne, et al. Expires February 20, 2008 [Page 5]
Internet-Draft Unauthenticated Emergency Service August 2007 3. Architecture For unauthenticated emergency services support it is insufficient to provide mechanisms only at the link layer in order to bypass authentication. A modification to the emergency services architecture is necessary since the IAP and the ISP need to make sure that the claimed emergency caller indeed performs an emergency call rather than using the network for other purposes, and thereby acting fraudulent by skipping any authentication, authorization and accounting procedures. Hence, without introducing some understanding of the specific application the ISP (and consequently the IAP) will not be able to detect and filter malicious activities. This leads to the architecture described in Figure 1 where the IAP needs to implement extensions to link layer procedures for unauthenticated emergency service access and the ISP needs to deploy emergency services related entities used for call routing, such as the Emergency Services Routing Proxy (ESRP), a Location Configuration Server (LCS) and a mapping database. On a very high-level, the interaction is as follows starting with the end host not being attached to the network and the user starting to make an emergency call. o Some radio networks have added support for unauthenticated emergency access, some other type of networks advertise these capabilities using layer beacons. The end host learns about these unauthenticated emergency services capabilities either from the link layer type or from advertisement. o The end host uses the link layer specific network attachment procedures defined for unauthenticated network access in order to get access to emergency services. o When the link layer network attachment procedure is completed the end host learns basic configuration information using DHCP from the ISP, including the address of the ESRP, as shown in (2). o When the IP address configuration is completed then the SIP UA initiates a SIP INVITE towards the indicated ESRP, as shown in (3). The INVITE message contains all the necessary parameters required by Section 4.1.4. o The ESRP receives the INVITE and processes it according to the description in Section 4.2.5. The location of the end host may need to be determined using a protocol interaction shown in (4). o Potentially, an interaction between the LCS of the ISP and the LCS of the IAP may be necessary, see (5). 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). Schulzrinne, et al. Expires February 20, 2008 [Page 6]
Internet-Draft Unauthenticated Emergency Service August 2007 o The PSAP evaluates the initial INVITE and acts according to SIP and the description in Section 4.3.4 in order to complete the call setup. o Finally, when the call setup is completed media traffic can be exchanged between the PSAP operator and the emergency caller, according to Section 4.3.5 and Section 4.1.5. For editorial reasons the end-to-end SIP and media exchange between the PSAP and SIP UA are not shown in Figure 1. Two important aspects are worth to highlight: o The IAP/ISP needs to understand the concept of emergency calls and 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 architecture. Other profiles may be added in the future, but the deployment effort is enormous since they have to be universally deployed. o The end host has no obligation to determine location information. It may attach location information if it has location available (e.g., from a GPS receiver). Figure 1 shows that the ISP needs to deploy SIP-based emergency services functionality. It is important to note that the ISP itself may outsource the functionality by simply providing access to them (e.g., it puts the IP address of an ESRP or a LoST server into an allow-list). For editorial reasons this outsourcing is not shown. Schulzrinne, et al. Expires February 20, 2008 [Page 7]
Internet-Draft Unauthenticated Emergency Service August 2007 +---------------------------+ | | | Emergency Network | | Infrastructure | | | | +----------+ +----------+ | | | PSAP | | ESRP | | | | | | | | | +----------+ +----------+ | +-------------------^-------+ | | (7) +------------------------+-----------------------+ | ISP | | | | | |+----------+ v | || Mapping | (6) +----------+ | || Database |<----->| ESRP / | | |+----------+ | SIP Proxy|<-+ | |+----------+ +----------+ | +----------+| || LCS-ISP | ^ | | DHCP || || |<---------+ | | Server || |+----------+ (4) | +----------+| +-------^-------------------------+-----------^--+ +-------|-------------------------+-----------|--+ | IAP | (5) | | | | V | | | |+----------+ | | | || LCS-IAP | +----------+ | | | || | | Link | |(3) | | |+----------+ | Layer | | | | | | Device | | (2)| | | +----------+ | | | | ^ | | | | | | | | +------------------------+--------+-----------+--+ | | | (1)| | | | | | | +----+ | v v | +----------+ | | End |<-------------+ | Host | +----------+ Figure 1: Unauthenticated Emergency Services Architecture Schulzrinne, et al. Expires February 20, 2008 [Page 8]
Internet-Draft Unauthenticated Emergency Service August 2007 4. Profile 4.1. End Host Profile 4.1.1. ESRP Discovery The end host MUST 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]. 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. 4.1.2. Location Determination and Location Configuration There is no requirement for end hosts to support any Location Configuration Protocol. If clients are in possession of location information, for example, based on a built-in GPS receiver then they SHOULD attach the location information in a PIDF-LO. When constructing the PIDF-LO the guidelines in PIDF-LO profile [I-D.ietf-geopriv-pdif-lo-profile] MUST be followed. For civic location information the format defined in [I-D.ietf-geopriv-revised-civic-lo] MUST be supported. 4.1.3. Emergency Call Identification To determine which calls are emergency calls, some entity needs to 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 mapping SHOULD performed at the endpoint device, but MAY be performed at an intermediate entity. End host MUST use the Service URN mechanism [I-D.ietf-ecrit-service-urn] to mark calls as emergency calls for their home emergency dial string. For visited emergency dial string the translation into a the Service URN mechanism is not mandatory since the ESRP in the ISPs network knows the visited emergency dial strings. 4.1.4. SIP Emergency Call Signaling SIP signaling capabilities [RFC3261] are mandated for end hosts. The initial SIP signaling method is an INVITE. Schulzrinne, et al. Expires February 20, 2008 [Page 9]
Internet-Draft Unauthenticated Emergency Service August 2007 1. The To: MUST be either a service URN in the "sos" tree or the visited emergency dial string. [I-D.rosen-iptel-dialstring] with the dialed digits. The sips URI [RFC3261] MUST NOT be used. 2. The From: header MUST be present and SHOULD be the AoR of the caller, if available. 3. A Via: header MUST be present and SHOULD include the URI of the device 4. A Route header SHOULD be present with the service URN in the "sos" tree, and the loose route parameter. 5. A Contact header MUST be present, which might contain a GRUU [I-D.ietf-sip-gruu], to permit an immediate call-back to the specific device that placed the emergency call. 6. Other headers MAY be included as per normal sip behavior 7. A Supported: header MUST be included with the 'geolocation' option tag [I-D.ietf-sip-location-conveyance], if the device understands the concept of SIP Location. In case that the device understands the SIP Location Conveyance [I-D.ietf-sip-location-conveyance] extension and has its location available, it MUST include location by-value. In this case, the INVITE contains a Supported header with a "geolocation" option tag, and a "cid-URL" [RFC2396] as the value in the Geolocation header, indicating which message body part contains the PIDF-LO. SIP Location Conveyance also requires that the UA MUST support multipart message bodies, since SDP will likely be also in the INVITE. 8. A normal SDP offer SHOULD be included in the INVITE. The offer MUST include the G.711 codec. 4.1.5. Media End points MUST send and receive media streams on RTP [RFC3550]. The SIP offer/answer [RFC3264] negotiations MUST be used to agree on the media streams to be used. End points supporting voice MUST support G.711 A law (and mu Law in North America) encoded voice as described in [RFC3551]. It is desirable to support wideband codecs in the offer. Silence suppression (Voice Activity Detection methods) MUST NOT be used on emergency calls. End points SHOULD support Instant Messaging using either [RFC3428] or [RFC3920]. End points SHOULD support real-time text [RFC4103]. The expectations for emergency service support for the real-time text medium, described in [I-D.ietf-sipping-toip], Section 7.1 SHOULD be fulfilled. Video may be important to support Video Relay Service (Sign language interpretation). End points supporting video MUST support H.264 per Schulzrinne, et al. Expires February 20, 2008 [Page 10]
Internet-Draft Unauthenticated Emergency Service August 2007 [RFC3984]. Support for video, instant messaging and real-time text is optional. 4.1.6. Testing The description in Section 9 of [I-D.ietf-ecrit-phonebcp] is applicable to this document as well. 4.2. ISP Profile 4.2.1. ESRP Discovery The ISP MUST implement the server side part of "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]. 4.2.2. Location Determination and Location Configuration The ISP must perform the necesary steps to determine the location of the end host. It is not necessary to standardize a specific mechanism. The usage of HELD [I-D.ietf-geopriv-http-location-delivery] with the identity extensions [I-D.winterbottom-geopriv-held-identity-extensions] may be a possible choice. It might be necessary for the ISP to talk to the IAP in order to determine the location of the end host. The work on LIS-to- LIS communication may be relevant, see [I-D.winterbottom-geopriv-lis2lis-req]. The ESRP (or a associated entity making location information available to the PSAP) MUST understand the PIDF-LO format [RFC4119], the PIDF-LO profile [I-D.ietf-geopriv-pdif-lo-profile] and the revised civic format [I-D.ietf-geopriv-revised-civic-lo]. Note that this architecture also fulfills the requirements for location hiding, see [I-D.schulzrinne-ecrit-location-hiding-requirements]. 4.2.3. Emergency Call Routing The ISP must route the emergency call to the PSAP responsible for the physical location of the end host. However, a standardized approach for determining the correct PSAP based on a given location may not be necessary. Schulzrinne, et al. Expires February 20, 2008 [Page 11]
Internet-Draft Unauthenticated Emergency Service August 2007 For cases where a standardized protocol should be used LoST [I-D.ietf-ecrit-lost] is a suitable mechanism. 4.2.4. Emergency Call Identification The ESRP MUST understand the Service URN mechanism [I-D.ietf-ecrit-service-urn] (i.e., the 'urn:service:sos' tree) and additionally the national emergency dial strings. The ESRP SHOULD perform a mapping of national emergency dial strings to Service URNs to simplify processing at PSAPs. 4.2.5. SIP Emergency Call Signaling SIP signaling capabilities [RFC3261] are mandated for the ESRP. The ESRP MUST process the messages sent by the client, as indicated in Section 4.1.4. Furthemore, the ESRP MUST be able to add a reference to location information, as described in SIP Location Conveyance [I-D.ietf-sip-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. 4.2.6. Quality of Service The ISP may provide QoS mechanisms to ensure the preferential treatment of emergency calls. The specific mechanisms depend on the network, may not require standardization and are outside the scope of this document. 4.3. PSAP Profile 4.3.1. Location Retrieval The PSAP MUST act according to SIP Location Conveyance when processing a request with location information. In particular, it MUST understand PIDF-LO format [RFC4119], the PIDF-LO profile [I-D.ietf-geopriv-pdif-lo-profile] and the revised civic format [I-D.ietf-geopriv-revised-civic-lo]. Furthermore, the PSAP MUST understand the SIP or SIPS dereference scheme. 4.3.2. Emergency Call Routing There might be additional emergency call routing applied within the PSAP operators network. This aspect is, however, outside the scope of this document. LoST [I-D.ietf-ecrit-lost] might be an appropriate way to determine the next ESRP or the final PSAP for routing the emergency call. Schulzrinne, et al. Expires February 20, 2008 [Page 12]
Internet-Draft Unauthenticated Emergency Service August 2007 4.3.3. Emergency Call Identification The ESRP MUST understand the Service URN mechanism [I-D.ietf-ecrit-service-urn] (i.e., the 'urn:service:sos' tree) and SHOULD understand national emergency dial strings. 4.3.4. SIP Emergency Call Signaling SIP signaling [RFC3261] is expected be supported by the PSAP. The ESRP MUST process the messages sent by the client, as indicated in Section 4.1.4. When receiving an emergency call the ESRP will dereference the reference to location information for dispatch. It MUST use the SIP or SIPS derefencing scheme todo so. 4.3.5. Media PSAPs MUST send and receive media streams on RTP [RFC3550]. The SIP offer/answer [RFC3264] negotiations MUST be used to agree on the media streams to be used. PSAPs supporting voice MUST support G.711 A law (and mu Law in North America) encoded voice as described in [RFC3551]. It is desirable to support wideband codecs in the offer. Silence suppression (Voice Activity Detection methods) MUST NOT be used on emergency calls. Depending on national regulations PSAPs MAY need to support Instant Messaging. If they need to provide this support then they MUST us either [RFC3428] or [RFC3920]. Depending on national regulations PSAPs MAY need to support real-time text [RFC4103]. If they need to provide this support then they MUST fulfill Section 7.1 of [I-D.ietf-sipping-toip]. Depending on national regulations PSAPs MAY need to video support for Video Relay Service (Sign language interpretation). If they need to provide this support then they MUST support H.264 per [RFC3984]. 4.3.6. Testing The description in Section 9 of [I-D.ietf-ecrit-phonebcp] is applicable to this document as well. 5. Example [Editor's Note: A WLAN hotspot or a DSL home network example could go in here.] Schulzrinne, et al. Expires February 20, 2008 [Page 13]
Internet-Draft Unauthenticated Emergency Service August 2007 6. Security Considerations The security threats discussed in [I-D.ietf-ecrit-security-threats] are applicable to this document. A number of security vulnerabilities discussed in [I-D.barnes-geopriv-lo-sec] around faked location information are less problematic in this case since location information does not need to be provided by the end host itself or it can be verified to fall within a specific geographical area. There are a couple of new vulnerabilities raised with unauthenticated emergency services since the PSAP operator does is not in possession of any identity information about the emergency call via the signaling path itself. In countries where this functionality is used for GSM networks today this has lead to a significant amount of misuse (see [reference-to-be-added]). The link layer mechanisms need to provide a special way of handling unauthenticated emergency services. Although this subject is not a topic for the IETF itself but there are at least a few high-level assumptions that may need to be collected. This includes security features that may be desireable. 7. Acknowledgments We would like to thank the authors of [I-D.ietf-ecrit-phonebcp] (James Polk and Brian Rosen) for their good work. This document makes heavy use of their document. From an editorial point of view a lot of text in this document can be replaced by references to [I-D.ietf-ecrit-phonebcp]. In order todo so it is necessary to make the text in that document easier to reference. This is subject of ongoing work. 8. Open Issues The following three high-level topics have been determined as open issues: o NAT Traversal: A certain NAT traversal story needs to be described and mandated. Most likely ICE for both the PSAP and the end host. o A DNS-based discovery procedure that discovers an ESRP in the local access network may need to be provided. o Text about link layer requirements are missing. These are necessary to make the "big picture" complete. 9. References Schulzrinne, et al. Expires February 20, 2008 [Page 14]
Internet-Draft Unauthenticated Emergency Service August 2007 9.1. Normative References [I-D.ietf-sip-location-conveyance] Polk, J. and B. Rosen, "Location Conveyance for the Session Initiation Protocol", draft-ietf-sip-location-conveyance-08 (work in progress), July 2007. [I-D.ietf-ecrit-service-urn] Schulzrinne, H., "A Uniform Resource Name (URN) for Emergency and Other Well-Known Services", draft-ietf-ecrit-service-urn-07 (work in progress), August 2007. [RFC4776] Schulzrinne, H., "Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Option for Civic Addresses Configuration Information", RFC 4776, November 2006. [RFC3825] Polk, J., Schnizlein, J., and M. Linsner, "Dynamic Host Configuration Protocol Option for Coordinate-based Location Configuration Information", RFC 3825, July 2004. [RFC4119] Peterson, J., "A Presence-based GEOPRIV Location Object Format", RFC 4119, December 2005. [I-D.ietf-geopriv-pdif-lo-profile] Tschofenig, H., "GEOPRIV PIDF-LO Usage Clarification, Considerations and Recommendations", draft-ietf-geopriv-pdif-lo-profile-08 (work in progress), July 2007. [I-D.ietf-geopriv-revised-civic-lo] Thomson, M. and J. Winterbottom, "Revised Civic Location Format for PIDF-LO", draft-ietf-geopriv-revised-civic-lo-05 (work in progress), February 2007. [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, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, Schulzrinne, et al. Expires February 20, 2008 [Page 15]
Internet-Draft Unauthenticated Emergency Service August 2007 June 2002. [I-D.rosen-iptel-dialstring] Rosen, B., "Dialstring parameter for the Session Initiation Protocol Uniform Resource Identifier", draft-rosen-iptel-dialstring-05 (work in progress), March 2007. [I-D.ietf-sip-gruu] Rosenberg, J., "Obtaining and Using Globally Routable User Agent (UA) URIs (GRUU) in the Session Initiation Protocol (SIP)", draft-ietf-sip-gruu-14 (work in progress), June 2007. [RFC2396] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998. [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with Session Description Protocol (SDP)", RFC 3264, June 2002. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, July 2003. [RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and Video Conferences with Minimal Control", STD 65, RFC 3551, July 2003. [RFC3428] Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C., and D. Gurle, "Session Initiation Protocol (SIP) Extension for Instant Messaging", RFC 3428, December 2002. [RFC4103] Hellstrom, G. and P. Jones, "RTP Payload for Text Conversation", RFC 4103, June 2005. [RFC3984] Wenger, S., Hannuksela, M., Stockhammer, T., Westerlund, M., and D. Singer, "RTP Payload Format for H.264 Video", RFC 3984, February 2005. [I-D.ietf-sipping-toip] Wijk, A. and G. Gybels, "Framework for real-time text over IP using the Session Initiation Protocol (SIP)", draft-ietf-sipping-toip-07 (work in progress), August 2006. [RFC3920] Saint-Andre, P., Ed., "Extensible Messaging and Presence Schulzrinne, et al. Expires February 20, 2008 [Page 16]
Internet-Draft Unauthenticated Emergency Service August 2007 Protocol (XMPP): Core", RFC 3920, October 2004. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [I-D.ietf-ecrit-phonebcp] Rosen, B. and J. Polk, "Best Current Practice for Communications Services in support of Emergency Calling", draft-ietf-ecrit-phonebcp-01 (work in progress), March 2007. 9.2. Informative References [I-D.ietf-ecrit-lost] Hardie, T., "LoST: A Location-to-Service Translation Protocol", draft-ietf-ecrit-lost-06 (work in progress), August 2007. [I-D.tschofenig-ecrit-architecture-overview] Tschofenig, H. and H. Schulzrinne, "Emergency Services Architecture Overview: Sharing Responsibilities", draft-tschofenig-ecrit-architecture-overview-00 (work in progress), July 2007. [I-D.ietf-geopriv-l7-lcp-ps] Tschofenig, H. and H. Schulzrinne, "GEOPRIV Layer 7 Location Configuration Protocol; Problem Statement and Requirements", draft-ietf-geopriv-l7-lcp-ps-03 (work in progress), July 2007. [I-D.ietf-ecrit-framework] Rosen, B., "Framework for Emergency Calling using Internet Multimedia", draft-ietf-ecrit-framework-02 (work in progress), July 2007. [I-D.marshall-geopriv-lbyr-requirements] Marshall, R., "Requirements for a Location-by-Reference Mechanism used in Location Configuration and Conveyance", draft-marshall-geopriv-lbyr-requirements-02 (work in progress), July 2007. [I-D.ietf-geopriv-http-location-delivery] Barnes, M., "HTTP Enabled Location Delivery (HELD)", draft-ietf-geopriv-http-location-delivery-01 (work in progress), July 2007. [I-D.ietf-ecrit-mapping-arch] Schulzrinne, H., "Location-to-URL Mapping Architecture and Schulzrinne, et al. Expires February 20, 2008 [Page 17]
Internet-Draft Unauthenticated Emergency Service August 2007 Framework", draft-ietf-ecrit-mapping-arch-02 (work in progress), July 2007. [I-D.ietf-ecrit-requirements] Schulzrinne, H. and R. Marshall, "Requirements for Emergency Context Resolution with Internet Technologies", draft-ietf-ecrit-requirements-13 (work in progress), March 2007. [I-D.winterbottom-geopriv-held-identity-extensions] Winterbottom, J. and M. Thomson, "HELD End-Point identity Extensions", draft-winterbottom-geopriv-held-identity-extensions-02 (work in progress), July 2007. [I-D.winterbottom-geopriv-lis2lis-req] Winterbottom, J. and S. Norreys, "LIS to LIS Protocol Requirements", draft-winterbottom-geopriv-lis2lis-req-00 (work in progress), June 2007. [I-D.ietf-ecrit-security-threats] Taylor, T., "Security Threats and Requirements for Emergency Call Marking and Mapping", draft-ietf-ecrit-security-threats-04 (work in progress), April 2007. [I-D.schulzrinne-ecrit-location-hiding-requirements] Schulzrinne, H., "Location Hiding: Problem Statement and Requirements", draft-schulzrinne-ecrit-location-hiding-requirements-00 (work in progress), July 2007. [I-D.barnes-geopriv-lo-sec] Barnes, R., "Threats to GEOPRIV Location Objects", draft-barnes-geopriv-lo-sec-00 (work in progress), July 2007. Schulzrinne, et al. Expires February 20, 2008 [Page 18]
Internet-Draft Unauthenticated Emergency Service August 2007 Authors' Addresses Henning Schulzrinne Columbia University Department of Computer Science 450 Computer Science Building New York, NY 10027 US Phone: +1 212 939 7004 Email: hgs+ecrit@cs.columbia.edu URI: http://www.cs.columbia.edu Stephen McCann Siemens/Roke Manor Research Email: stephen.mccann@roke.co.uk Gabor Bajko Nokia Email: Gabor.Bajko@nokia.com Hannes Tschofenig Nokia Siemens Networks Otto-Hahn-Ring 6 Munich, Bavaria 81739 Germany Email: Hannes.Tschofenig@nsn.com URI: http://www.tschofenig.com Schulzrinne, et al. Expires February 20, 2008 [Page 19]
Internet-Draft Unauthenticated Emergency Service August 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Schulzrinne, et al. Expires February 20, 2008 [Page 20]