ECRIT H. Schulzrinne
Internet-Draft Columbia University
Intended status: Standards Track S. McCann
Expires: May 22, 2008 Siemens/Roke Manor Research
G. Bajko
Nokia
H. Tschofenig
Nokia Siemens Networks
November 19, 2007
Extensions to the Emergency Services Architecture for dealing with
Unauthenticated and Unauthorized Devices
draft-schulzrinne-ecrit-unauthenticated-access-01.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 May 22, 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 May 22, 2008 [Page 1]
Internet-Draft Unauthenticated Emergency Service November 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 May 22, 2008 [Page 2]
Internet-Draft Unauthenticated Emergency Service November 2007
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. A Warning Note . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 7
5. Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1. End Host Profile . . . . . . . . . . . . . . . . . . . . . 10
5.1.1. ESRP Discovery . . . . . . . . . . . . . . . . . . . . 10
5.1.2. Location Determination and Location Configuration . . 10
5.1.3. Emergency Call Identification . . . . . . . . . . . . 10
5.1.4. SIP Emergency Call Signaling . . . . . . . . . . . . . 11
5.1.5. Media . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1.6. Testing . . . . . . . . . . . . . . . . . . . . . . . 11
5.2. ISP Profile . . . . . . . . . . . . . . . . . . . . . . . 11
5.2.1. ESRP Discovery . . . . . . . . . . . . . . . . . . . . 11
5.2.2. Location Determination and Location Configuration . . 11
5.3. ESRP Profile . . . . . . . . . . . . . . . . . . . . . . . 12
5.3.1. Emergency Call Routing . . . . . . . . . . . . . . . . 12
5.3.2. Emergency Call Identification . . . . . . . . . . . . 12
5.3.3. SIP Emergency Call Signaling . . . . . . . . . . . . . 12
5.3.4. Location Retrieval . . . . . . . . . . . . . . . . . . 12
5.4. PSAP Profile . . . . . . . . . . . . . . . . . . . . . . . 12
5.4.1. Location Retrieval . . . . . . . . . . . . . . . . . . 13
5.4.2. Emergency Call Routing . . . . . . . . . . . . . . . . 13
5.4.3. Emergency Call Identification . . . . . . . . . . . . 13
5.4.4. SIP Emergency Call Signaling . . . . . . . . . . . . . 13
5.4.5. Media . . . . . . . . . . . . . . . . . . . . . . . . 13
5.4.6. Testing . . . . . . . . . . . . . . . . . . . . . . . 13
6. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
7. Security Considerations . . . . . . . . . . . . . . . . . . . 14
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
9. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 14
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
10.1. Normative References . . . . . . . . . . . . . . . . . . . 15
10.2. Informative References . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
Intellectual Property and Copyright Statements . . . . . . . . . . 21
Schulzrinne, et al. Expires May 22, 2008 [Page 3]
Internet-Draft Unauthenticated Emergency Service November 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 excercised 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 providers, 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
standardized although [I-D.ietf-ecrit-phonebcp] provides best current
practise recommendations regarding the usage of certain features as
excercised 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 May 22, 2008 [Page 4]
Internet-Draft Unauthenticated Emergency Service November 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 emergency services architecture, described in
[I-D.ietf-ecrit-framework].
2. A Warning Note
At the time of writing there is no regulation in place that demands
the functionality described in this memo. 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.
There are also indications that the functionality of unauthenticated
emergency calls in today's cellular system (called SIM-less calls) in
certain countries leads to a fair amount of hoaks calls or test calls
leading to overload situations at PSAPs.
As an example, Federal Office of Communications (OFCOM, Switzerland)
provided statistics about 112 calls in Switzerland from Jan. 1997 to
Nov. 2001. Switzerland did not offer SIM-less emergency calls except
for almost a month in July 2000 where a significant increase in hoaks
and test calls was reported. As a consequence, the functionality was
disabled again. More details can be found in the panel presentations
of the 3rd SDO Emergency Services Workshop [esw07].
3. 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 the following new terms:
Schulzrinne, et al. Expires May 22, 2008 [Page 5]
Internet-Draft Unauthenticated Emergency Service November 2007
Un-initialized Device:
A device without VoIP client software.
Non-service-initialized Device:
A device for which there is no valid service contract with a
provider of the services enumerated in paragraph (a) of this
section. Other terms: "un-activated", "un-provisioned",
"unbranded", "non-service-initialized" device.
Unauthenticated Emergency Service:
The term "unauthenticated emergency services" refers to the case
where an emergency caller does not have credentials (e.g., no SIM
card, no username and password, no private key) to either attach
to network or for usage with a VoIP service or both. Still, the
device is granted (limited) access to perform emergency calling.
It is important to differentiate between the unavailability of
credentials for network access and for VoIP access as the network
provider and the VoIP provider are often distinct entities and
therefore the user might have different credentials with the two.
Unauthorized Emergency Service:
The term "unauthorized emergency services" refers to the case
where a device aims to attach to the network or to use a VoIP
service but the authorization procedure fails. The authorization
step may fail as a consequence of triggering different procedures
(such as network access authentication or registration at the VoIP
providers registrar). Still, the device is granted (limited)
access to perform emergency calling. It is important to
differentiate between network operator and VoIP provider as they
often refer to different parties and therefore the authorization
decision might be executed by a different backend infrastructure.
Lack of authorization might be caused by a number of reasons,
including credit exhaustion, expired accounts, locked account,
missing access rights (e.g., access to the competitors enterprise
network), etc.
This document reuses terminology from [I-D.ietf-geopriv-l7-lcp-ps]
and [I-D.ietf-ecrit-requirements], namely Internet Access Provider
(IAP), Internet Service Provider (ISP), Application Service Provider
(ASP), Voice Service Provider (VSP), Emergency Service Routing Proxy
(ESRP), Public Safety Answering Point (PSAP), Location Configuration
Server (LCS), (emergency) service dial string, and (emergency)
Schulzrinne, et al. Expires May 22, 2008 [Page 6]
Internet-Draft Unauthenticated Emergency Service November 2007
service identifier.
4. 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 5.1.4.
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
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).
Schulzrinne, et al. Expires May 22, 2008 [Page 7]
Internet-Draft Unauthenticated Emergency Service November 2007
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 acts according to SIP
and the description in Section 5.4.4 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 5.4.5 and Section 5.1.5.
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 May 22, 2008 [Page 8]
Internet-Draft Unauthenticated Emergency Service November 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 May 22, 2008 [Page 9]
Internet-Draft Unauthenticated Emergency Service November 2007
It is important to note that a single ESRP may also offer it's
service to several ISPs.
5. Profiles
5.1. End Host Profile
5.1.1. 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.
5.1.2. 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.
5.1.3. 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 be performed at the endpoint device.
End hosts MUST use the Service URN mechanism
[I-D.ietf-ecrit-service-urn] to mark calls as emergency calls for
their home emergency dial string (if known). 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.
Schulzrinne, et al. Expires May 22, 2008 [Page 10]
Internet-Draft Unauthenticated Emergency Service November 2007
5.1.4. SIP Emergency Call Signaling
SIP signaling capabilities [RFC3261] are mandated for end hosts.
The initial SIP signaling method is an INVITE. The SIP INVITE
request MUST be constructed according to the requirements in Section
9.2 [I-D.ietf-ecrit-phonebcp].
Regarding callback behavior SIP UAs MUST have a globally routable URI
in a Contact: header.
5.1.5. Media
End points MUST comply with the media requirements for end points
placing an emergency call found in Section 14 of
[I-D.ietf-ecrit-phonebcp].
5.1.6. Testing
The description in Section 15 of [I-D.ietf-ecrit-phonebcp] is fully
applicable to this document.
5.2. ISP Profile
5.2.1. 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 IPv4) and / or the "Dynamic
Host Configuration Protocol (DHCPv6) Options for Session Initiation
Protocol (SIP) Servers" [RFC3319].
5.2.2. Location Determination and Location Configuration
The ISP must perform the neccesary steps to determine the location of
the end host. It is not necessary to standardize a specific
mechanism.
The role of the ISP is to operate the LIS. 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].
Schulzrinne, et al. Expires May 22, 2008 [Page 11]
Internet-Draft Unauthenticated Emergency Service November 2007
5.3. ESRP Profile
5.3.1. Emergency Call Routing
The ESRP 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
is useful but not mandatory.
For cases where a standardized protocol is used LoST
[I-D.ietf-ecrit-lost] is a suitable mechanism.
5.3.2. 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.
5.3.3. SIP Emergency Call Signaling
SIP signaling capabilities [RFC3261] are mandated for the ESRP. The
ESRP MUST process the messages sent by the client, according to
Section 5.1.4. Furthermore, 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.
5.3.4. Location Retrieval
The ESRP acts a location recipient and 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. 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.
5.4. PSAP Profile
Schulzrinne, et al. Expires May 22, 2008 [Page 12]
Internet-Draft Unauthenticated Emergency Service November 2007
5.4.1. 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] (including all shape types) and
the revised civic format [I-D.ietf-geopriv-revised-civic-lo]
(including the civic location tokens applicable for the geographial
region the PSAP is responsible for). Furthermore, the PSAP MUST
understand the SIP or SIPS dereference scheme (see
[I-D.ietf-sip-location-conveyance]) and the HELD dereferencing
protocol (see [I-D.winterbottom-geopriv-deref-protocol]).
5.4.2. 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.
5.4.3. Emergency Call Identification
The PSAP MUST understand the Service URN mechanism
[I-D.ietf-ecrit-service-urn] (i.e., the 'urn:service:sos' tree).
5.4.4. SIP Emergency Call Signaling
SIP signaling [RFC3261] is expected be supported by the PSAP. The
PSAP MUST process the messages sent by the client, as indicated in
Section 5.1.4. When receiving an emergency call the ESRP will
dereference the reference to location information for dispatch.
5.4.5. Media
The PSAP MUST process the media traffic sent by the client, as
indicated in Section 5.1.5.
5.4.6. Testing
The PSAP MUST process the signaling messages sent by the client, as
indicated in Section 5.1.6.
6. Example
[Editor's Note: A WLAN hotspot or a DSL home network example could go
Schulzrinne, et al. Expires May 22, 2008 [Page 13]
Internet-Draft Unauthenticated Emergency Service November 2007
in here.]
7. 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.
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 desirable.
8. 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.
We would like to thank members from the Wimax Forum for their help
with the terminology. We would also like to thank the participants
of the 2nd and 3rd SDO Emergency Services Workshop for their input
regarding this subject.
9. 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.
Schulzrinne, et al. Expires May 22, 2008 [Page 14]
Internet-Draft Unauthenticated Emergency Service November 2007
o Text about link layer requirements are missing. These are
necessary to make the "big picture" complete.
o EAP method for emergency calls: Some of the discussions around the
liaison request from the IEEE to the IETF EMU WG need to get
reflected.
o Quality of Service treatment for emergency calls has not been
described in this document
10. References
10.1. 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]
Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV
PIDF-LO Usage Clarification, Considerations and
Recommendations", draft-ietf-geopriv-pdif-lo-profile-10
(work in progress), October 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-06 (work in progress),
October 2007.
Schulzrinne, et al. Expires May 22, 2008 [Page 15]
Internet-Draft Unauthenticated Emergency Service November 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,
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-15 (work in progress),
October 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.
Schulzrinne, et al. Expires May 22, 2008 [Page 16]
Internet-Draft Unauthenticated Emergency Service November 2007
[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-08 (work in progress),
October 2007.
[RFC3920] Saint-Andre, P., Ed., "Extensible Messaging and Presence
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.winterbottom-geopriv-deref-protocol]
Winterbottom, J., Tschofenig, H., Schulzrinne, H.,
Thomson, M., and M. Dawson, "An HTTPS Location
Dereferencing Protocol Using HELD",
draft-winterbottom-geopriv-deref-protocol-00 (work in
progress), November 2007.
[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-03 (work in progress),
November 2007.
10.2. 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-05 (work in
progress), September 2007.
Schulzrinne, et al. Expires May 22, 2008 [Page 17]
Internet-Draft Unauthenticated Emergency Service November 2007
[I-D.ietf-ecrit-framework]
Rosen, B., Schulzrinne, H., Polk, J., and A. Newton,
"Framework for Emergency Calling using Internet
Multimedia", draft-ietf-ecrit-framework-04 (work in
progress), November 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., Winterbottom, J., Thomson, M., and B. Stark,
"HTTP Enabled Location Delivery (HELD)",
draft-ietf-geopriv-http-location-delivery-03 (work in
progress), November 2007.
[I-D.ietf-ecrit-mapping-arch]
Schulzrinne, H., "Location-to-URL Mapping Architecture and
Framework", draft-ietf-ecrit-mapping-arch-03 (work in
progress), September 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 Device identity
Extensions",
draft-winterbottom-geopriv-held-identity-extensions-03
(work in progress), October 2007.
[I-D.winterbottom-geopriv-lis2lis-req]
Winterbottom, J. and S. Norreys, "LIS to LIS Protocol
Requirements", draft-winterbottom-geopriv-lis2lis-req-01
(work in progress), November 2007.
[I-D.ietf-ecrit-security-threats]
Taylor, T., "Security Threats and Requirements for
Emergency Call Marking and Mapping",
draft-ietf-ecrit-security-threats-05 (work in progress),
August 2007.
[I-D.schulzrinne-ecrit-location-hiding-requirements]
Schulzrinne, H., "Location Hiding: Problem Statement and
Schulzrinne, et al. Expires May 22, 2008 [Page 18]
Internet-Draft Unauthenticated Emergency Service November 2007
Requirements",
draft-schulzrinne-ecrit-location-hiding-requirements-01
(work in progress), August 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.
[esw07] "3rd SDO Emergency Services Workshop,
http://www.emergency-services-coordination.info/2007Nov/",
October 30th - November 1st 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
Schulzrinne, et al. Expires May 22, 2008 [Page 19]
Internet-Draft Unauthenticated Emergency Service November 2007
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 May 22, 2008 [Page 20]
Internet-Draft Unauthenticated Emergency Service November 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 May 22, 2008 [Page 21]