ECRIT J. Winterbottom Internet-Draft CommScope Intended status: Standards Track H. Tschofenig Expires: January 8, 2013 Nokia Siemens Networks July 7, 2012 Out of Jurisdiction Emergency Routing draft-winterbottom-ecrit-priv-loc-00 Abstract Some countries and regions require location information be constrained to emergency service applications and do not permit location information to traverse the end-point at all. This document describes the requirements of these countries and provides a solution based on an extension to the HELD location protocol. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months 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." This Internet-Draft will expire on January 8, 2013. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as Winterbottom & Tschofenig Expires January 8, 2013 [Page 1] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 described in the Simplified BSD License. Table of Contents 1. Introduction and Motivation . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Problem Description . . . . . . . . . . . . . . . . . . . . . 5 4. Key Observations . . . . . . . . . . . . . . . . . . . . . . . 6 5. Available Building Blocks . . . . . . . . . . . . . . . . . . 7 6. The Missing Link . . . . . . . . . . . . . . . . . . . . . . . 8 6.1. Call Flow . . . . . . . . . . . . . . . . . . . . . . . . 9 6.2. Domain Breakdown . . . . . . . . . . . . . . . . . . . . . 10 7. Privacy Considerations . . . . . . . . . . . . . . . . . . . . 11 8. Security Considerations . . . . . . . . . . . . . . . . . . . 11 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 11.1. Normative References . . . . . . . . . . . . . . . . . . . 12 11.2. Informative References . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 Winterbottom & Tschofenig Expires January 8, 2013 [Page 2] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 1. Introduction and Motivation The Internet emergency calling architecture specified in [I-D.ietf-ecrit-phonebcp] describes two main models for emergency call processing. The first is a device-centric model, where a device obtains location information using a location configuration protocol, such a HELD [RFC5985], and then proceeds to determine the address of the next hop closer to the local PSAP using LoST [RFC5222]. Figure 1 shows this model in a simplified form. +---Location Request---+ | (1) | +---+----+ +---V---+ | |<--Location--| LIS | | Caller | (2) +-------+ +--------+ | | | ESRP/ | | |----Find Service-------+ | PSAP | +------^-+ (3) | +--------+ | | +--------V----+ ^ | +-----Service----| LoST Server | | | (4) +-------------+ +---+---+ +-------------Call Initiation------------>| VSP | (5) +-------+ Figure 1: Device-Centric Emergency Services Model With the ever increasing deployment of smart phones and tablet devices a variation of the device-centric model is the ability to use location available to the device for routing and then consult a LIS when location is needed for dispatch. Location can come in various forms to the device, e.g., from GPS, third party location databases, as well as IP-to-geolocation services. The second approach is a softswitch-centric model, where a device initiates and emergency call and the serving softswitch detects that the call is an emergency and initiates retrieving the caller's location from a Location Information Server (LIS) using HELD [RFC5985] with identity extensions [RFC6155] and then determining the route to the local PSAP using LoST [RFC5222]. Figure 2 shows the high-level protocol interactions. Winterbottom & Tschofenig Expires January 8, 2013 [Page 3] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 +---Location Request---+ | (2) | +---V---+ | | LIS | | +----+--+ +----+----+ | | | +----Location--->| Soft | +--------+ (3) | Switch | | Caller |------Call Initiation------------> | | +--------+ (1) +-+-^---+-+ +-------------+ | | | | LoST Server |<-Find Service--+ | | +------+------+ (4) | | | | | +----------Service--------+ | (5) | +-----------+ | | ESRP/PSAP |<------Call----+ +-----------+ (6) Figure 2: Softswitch-Centric Calling Model In the softswitch-centric model when a VSP receives an emergency call it will encounter several difficulties. The first hurdle is for the VSP to determine the correct LIS to ask for location information. Having obtained the location, the VSP must then determine the correct PSAP using a LoST server and this requires wide-spread deployment of forest guides. This leads to a failure in the softswitch-centric approach to deliver emergency calls correctly because the VSP is unable to determine the correct PSAP to route the call to. The softswitch-centric model should therefore seen only as a transition architecture towards the end-device model where end devices have not been upgraded. Software updates of end devices are, however, not a problem anymore since software updates have to be provided to end devices on a regular basis to patch security vulnerabilities. Any service provider that does not have an ability to update devices will not only put their own customers at risk but also other Internet users as well since those can become the victims of attacks as well. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. The terms LIS, ESRP, VSP and PSAP are used as defined in [RFC6443]. Winterbottom & Tschofenig Expires January 8, 2013 [Page 4] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 The term "Access Network Provider" is used as defined in [RFC5687] and incompasses both the Internet Access Provider (IAP) and Internet Service Provider (ISP). 3. Problem Description There is a significant faction in the emergency services and the regulatory community that do not want to rely on emergency calls solutions with end-device provided location. This includes location information that is determined by the network but subsequently traverses the end-point prior to being delivered to the emergency organization. There are two concerns: Security: One concern is about the possibility of the software of the end device being able to tamper with location. This can lead to denial of service attacks against the emergency services infrastructure. [I-D.ietf-ecrit-trustworthy-location] describes these concerns in detail. Privacy: There is the desire to allow location information to be provided to emergency organizations rather than any other party, including the end device or a VSP. In the softswitch model the VSP would have to ask the access provider for location information. However, the number of VSPs asking for location information could, at least in theory depending on the scope of emergency services regulation be very large and is likely to include VSPs that are located in a jurisdiction that is different from the one of the access network provider. Allowing VSPs to ask for location information of end devices at access network providers in a third party fashion without the ability to present the user's consent or the emergency service nature calls for privacy problems. [RFC6155] discusses some of these privacy challenges as part of the third party requests. These arguments may, however, also jacked into place to hide another reason, namely the desire to create an artifical relationship between the VSP and the access network provider. [RFC6444] provides a problem description and [I-D.ietf-ecrit-rough-loc] even offers a solution based on rough location. This solutions, however, requires the access network provider to compute these rough location shapes. Countries that have a large number of PSAPs and neither an ESRP nor a stage-1 PSAP architecture may encounter problems computing these shapes. The Internet calling model does not constrain the call to a single Winterbottom & Tschofenig Expires January 8, 2013 [Page 5] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 jurisdictional boundary nor does it assume that the Voice Service provider (VSP) role is provided by the access provider. This allows the VSP to be located anywhere on the Internet without requiring any association with Internet access providers. +----------------+ +----------------+ +----------------+ | Jurisdiction 1 | | Jurisdiction 2 | | Jurisdiction 3 | | | | | | | | | | | | | | +--------------+--+----------------+--+--------------+ | | | EMERGENCY CALL CENTRES | | | +--------------+--+----------------+--+--------------+ | | ^ ^ ^ | | | | | | | | | | | | | | | +-----+ | | | | +-----+ | | +-----+ | | | VSP | | +--------| VSP | | | | VSP | | | +--^--+ | | | +---^-+ | | +-----+ | | | | | | | | | | | +--------+-----+--+-------+--------+--+--------------+ | | | | | | INTERNET | | | +--------+-----+--+-----+----------+--+--------------+ | | | | | | | | | | | +--------+-----+--+-------+--------+--+--------------+ | | | | | ACCESS | NETWORKS | | | +--------------+--+-------+--------+--+--------------+ | | | | | | | | | | | | | +-------------+ | | | | | | | | | | | | | +------------+ | | | | | | | EMERGENCY | | | | | | | | CALLS | | | | | | | +------------+ | | | | | | +--------+-----+--+-----+----------+--+--------------+ | | | | | DEVICES | | | +--------------+--+-----+----------+--+--------------+ | | | | | | | +----------------+ +----------------+ +----------------+ e.g US State e.g. Australia e.g. European Country Figure 3: Internet Calling Models 4. Key Observations When these security and privacy requirements are taken into consideration then the emergency calling architecture and associated Winterbottom & Tschofenig Expires January 8, 2013 [Page 6] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 procedures described in [I-D.ietf-ecrit-phonebcp] and [RFC6443] require some adaptation in some configurations to ensure universal operation. The softswitch model fails to meet the privacy requirements and the end-device model has to wrangle with security challenges. Several observations have been posed thus far: Problem#1: Rough location information is required to route emergency calls. Problem#2: The VSP needs the ability to determine the correct LIS to retrieve location information. Problem#3: The VSP needs the ability to contact a LoST server to acquire routing information from. Problem#4: The end host does not acquire or convey location to the emergency network. Problem#5: Access network provider aim to provide location only to emergency service authorities. Problem#6: Precise location information is required to dispatch first responders. 5. Available Building Blocks To fulfill A number of building blocks are already available. There is no need to start from a clean sheet. Location: Location standards have existed for mobile cellular networks since the mid to late 1990s, and location standards for the Internet have existed since the mid to late 2000s. The exact determination techniques for each access technology are different but the ability to direct communications across a communications network is inherenetly premised on being able to reach a specific device and this requires some knowledge of where the device is physically located. The term Location Information Server (LIS) is used to identify the element in an access network responsible for providing the location of a device in its administrative domain. LIS service discovery techniques are described in [RFC5986] and [I-D.ietf-geopriv-res-gw-lis-discovery]. Winterbottom & Tschofenig Expires January 8, 2013 [Page 7] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 Call Routing: The LoST protocol [RFC5222] specifies a means to map location and service information into a destination URI. Next generation emergency services architectures and procedures, such as those defined in [RFC6443], NENA i3, and the EENA NG112 document, use LoST for providing routing to local emergency service authorities. LoST servers are discovered using DNS U-NAPTR [RFC4848] to obtain a service URI. The discovered LoST server services the domain in which the device is resident, or is able to provide the identity of a LoST server that can service the request. A access network provider that operates in an area capable of receiving next generation emergency calls is able to include a U-NAPTR record in their DNS servers that identifies the local serving LoST server able to resolve emergency routing requests. LIS Discovery: [I-D.ietf-geopriv-res-gw-lis-discovery] provides a means for discovering a LIS based on the IP address of a device and this could be used in conjunction with [RFC6155] to provide a solution to problem 2. The domain name discovered for the LIS could be reused to discover the correct LoST server to contact thereby solving problem 3. 6. The Missing Link Problem 5 does not allow the LIS to provide location information except to emergency authorities, and while the HELD protocol [RFC5985] does allow a location URI to be returned to the requesting entitiy, the LoST protocol [RFC5222] requires a location value and does not support a location reference. One possible solution to problem 5 is to extend LoST to support a location URI in the findService request method. In this case a VSP would detect that a device was making an emergency call, determine the correct LIS to contact using [I-D.ietf-geopriv-res-gw-lis-discovery], contact the LIS using HELD [RFC5985] using the IP address of the calling device as an identity extension [RFC6155] and the LIS would respond with a location URI that requires client-side authentication for dereferencing Using the LIS domain identifier the VSP would then determine the correct LoST server and request emergency services using the location URI as the location reference. The LoST server must have permission to dereference the location URI, if any form of recurision is encountered then the URI must be dereferenced multiple times increasing the likelihood of failure. An alternative approach is to leave LoST unchanged, but extend the HELD protocol and requirements of the local LIS. In this solution, Winterbottom & Tschofenig Expires January 8, 2013 [Page 8] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 when the LIS receives the third-party request, it performs the necessary LoST request using the location of the device. The LIS responds with a location URI and the destination URI of the correct emergency service authority. The Location URI will only yield location information to the authorized emergency authority. This solution addresses problem 1 problem 3, problem 4, problem 5. Problem 2 is solved using a combination of [I-D.ietf-geopriv-res-gw-lis-discovery] and HELD with identity extensions. 6.1. Call Flow 1. Device initiates an emergency call to home VSP 2. Home VSP detects emergency call and uses IP address to determine the correct LIS to query using [I-D.ietf-geopriv-res-gw-lis-discovery]. 3. Home VSP queries the LIS using HELD and the IP address of the calling device as an identity extension. 4. The LIS determines the location and uses it request routing information for the local LoST server. 5. The LIS return a location URI and the local Emergency Service Routing Proxy (ESRP) URI to the home VSP. 6. The VSP follows the guidance from [I-D.ietf-ecrit-phonebcp] and routes the call to the ESRP. 7. The ESRP authenticates itself with the LIS when it dereferences the location URI. 8. The returns location information to the ESRP allowing it route the call to the correct PSAP. Winterbottom & Tschofenig Expires January 8, 2013 [Page 9] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 +------(2)Find LIS-----+ | | +---V---+ | | DNS | | +----+--+ +----+---------+ | | | +----LIS URI---->| Home | +--------+ | VSP | | Caller |------(1)-Call Initiation--------> | | +--------+ +-+--^-------+-+ | | | +-------------+ | | | | |<------(3)-locationReq(IP)-------+ | | | LIS | | | | |--(5)-locationResp(locURI,EcrfURI)--+ | +-+--^---+--^-+ | | | | | +-------------+ | | | | +-----Service----+ | | | | | | LoST Server | | | | +-(4)-Find Service->| | | | | +-------------+ | | | | | | +-----------+ | | +--(7)-locReq(Auth)--+ | | | | ESRP/PSAP |<--(6)-Call(locURI)-+ +---(8)-locResp(Loc)--->| | +-----------+ Figure 4: Modified Softswitch-Centric Emergency Call Flow 6.2. Domain Breakdown The key advantage of the call flow show in Section 6.1 is that it separates the entities into two clear groups, those that are inside the regulatory emergency jurisdiction and those that are in the Internet. This is evident in Figure 5. Winterbottom & Tschofenig Expires January 8, 2013 [Page 10] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 +------(2)Find LIS-----+ | | +---V---+ | | DNS | | +----+--+ +----+---------------+ | | | +----LIS URI---->| Home | | VSP | | | +-^---+----^-------+-+ I N T E R N E T | | | | =========================================|===|====|=======|=== LOCAL JURISDICTION | | | | +--------+ | | | | | Caller |------(1)-Call Initiation------+ | | | +--------+ | | | | | | +-------------+ | | | | |<------(3)-locationReq(IP)-----+ | | | LIS | | | | |--(5)-locationResp(locURI,EcrfURI)--+ | +-+--^---+--^-+ | | | | | +-------------+ | | | | +-----Service----+ | | | | | | LoST Server | | | | +-(4)-Find Service->| | | | | +-------------+ | | | | | | +-----------+ | | +--(7)-locReq(Auth)--+ | | | | ESRP/PSAP |<--(6)-Call(locURI)-+ +---(8)-locResp(Loc)--->| | +-----------+ Figure 5: Emergency Call Domains 7. Privacy Considerations [[TBD.]] 8. Security Considerations [[TBD.]] Winterbottom & Tschofenig Expires January 8, 2013 [Page 11] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 9. IANA Considerations [[TBD.]] 10. Acknowledgements We would like to thank Wilfried Lange for sharing his views with us. 11. References 11.1. Normative References [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-20 (work in progress), September 2011. [I-D.ietf-geopriv-deref-protocol] Winterbottom, J., Tschofenig, H., Schulzrinne, H., and M. Thomson, "A Location Dereferencing Protocol Using HELD", draft-ietf-geopriv-deref-protocol-05 (work in progress), May 2012. [I-D.ietf-geopriv-res-gw-lis-discovery] Thomson, M. and R. Bellis, "Location Information Server (LIS) Discovery using IP address and Reverse DNS", draft-ietf-geopriv-res-gw-lis-discovery-03 (work in progress), March 2012. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5222] Hardie, T., Newton, A., Schulzrinne, H., and H. Tschofenig, "LoST: A Location-to-Service Translation Protocol", RFC 5222, August 2008. [RFC5687] Tschofenig, H. and H. Schulzrinne, "GEOPRIV Layer 7 Location Configuration Protocol: Problem Statement and Requirements", RFC 5687, March 2010. [RFC5985] Barnes, M., "HTTP-Enabled Location Delivery (HELD)", RFC 5985, September 2010. [RFC5986] Thomson, M. and J. Winterbottom, "Discovering the Local Location Information Server (LIS)", RFC 5986, Winterbottom & Tschofenig Expires January 8, 2013 [Page 12] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 September 2010. [RFC6155] Winterbottom, J., Thomson, M., Tschofenig, H., and R. Barnes, "Use of Device Identity in HTTP-Enabled Location Delivery (HELD)", RFC 6155, March 2011. [RFC6443] Rosen, B., Schulzrinne, H., Polk, J., and A. Newton, "Framework for Emergency Calling Using Internet Multimedia", RFC 6443, December 2011. 11.2. Informative References [I-D.ietf-ecrit-rough-loc] Barnes, R. and M. Lepinski, "Using Imprecise Location for Emergency Context Resolution", draft-ietf-ecrit-rough-loc-04 (work in progress), March 2011. [I-D.ietf-ecrit-trustworthy-location] Tschofenig, H., Schulzrinne, H., and B. Aboba, "Trustworthy Location Information", draft-ietf-ecrit-trustworthy-location-03 (work in progress), April 2012. [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, November 2003. [RFC4079] Peterson, J., "A Presence Architecture for the Distribution of GEOPRIV Location Objects", RFC 4079, July 2005. [RFC4848] Daigle, L., "Domain-Based Application Service Location Using URIs and the Dynamic Delegation Discovery Service (DDDS)", RFC 4848, April 2007. [RFC5012] Schulzrinne, H. and R. Marshall, "Requirements for Emergency Context Resolution with Internet Technologies", RFC 5012, January 2008. [RFC5774] Wolf, K. and A. Mayrhofer, "Considerations for Civic Addresses in the Presence Information Data Format Location Object (PIDF-LO): Guidelines and IANA Registry Definition", BCP 154, RFC 5774, March 2010. [RFC6444] Schulzrinne, H., Liess, L., Tschofenig, H., Stark, B., and A. Kuett, "Location Hiding: Problem Statement and Requirements", RFC 6444, January 2012. Winterbottom & Tschofenig Expires January 8, 2013 [Page 13] Internet-Draft Out of Jurisdiction Emergency Routing July 2012 Authors' Addresses James Winterbottom CommScope Suit 1, Level 2 iC Enterprise 1, Innovation Campus Squires Way North Wollongong, NSW 2500 AU Phone: +61 242 212938 Email: james.winterbottom@commscope.com Hannes Tschofenig Nokia Siemens Networks Linnoitustie 6 Espoo 02600 Finland Phone: +358 (50) 4871445 Email: Hannes.Tschofenig@gmx.net URI: http://www.tschofenig.priv.at Winterbottom & Tschofenig Expires January 8, 2013 [Page 14]