1 © 2004, Cisco Systems, Inc. All rights reserved. VVT-A01 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public SIP Location Conveyance draft-ietf-sip-location-conveyance-04.txt James Polk Brian Rosen Oct 5th/6th, 2006 Needs changes to be made!!!!

2 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public Location Conveyance Based on Presence Information Data Format (PIDF) for Location Objects (LO) as defined in the Geopriv Working Group of IETF – simply PIDF-LO PIDF-LO uses GML (Geography Markup Language from OpenGIS) 2 Location Representations are specified: – Civil Addressing (basically Post Office addresses which are internationalized) – Coordinate or Geodetic (Lat/Long/Alt with datum) Two types of Location Conveyance in SIP: – User-to-User (I want to tell you where I am, have been or will be) – Routing based on UAC location (Proxies need to know my location to properly route the SIP Request (shown in Emergency example)) draft-ietf-sip-location-conveyance draft-ietf-geopriv-dhcp-civil RFC 3825 Coordinate Location in DHCP RFC 4119 Geopriv PIDF-LO

3 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public The Session Initiation Protocol (SIP) is an application layer control (signaling) protocol for: – creating – modifying and – terminating multimedia sessions with one or more participants SIP Basics RFC 3261

4 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public SIP components include: User Agents (UAs) Gateways Registrar Servers Proxy Servers – have degrees of statefulness – CSCF(s), B2BUAs, SBCs Redirect Servers SIP Basics (cont’d)

5 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public IHLTotal Length IdentificationFlagsFragment Offset Header ChecksumProtocolTime to Live Source Address Destination Address PaddingOptions Version DSCP ECN IPv4 Header is 20 Bytes and Binary Source Port Destination Port Checksum Length UDP Header is 8 Bytes and Binary (Layer 4 here could also be TCP or SCTP) SIP Headers in US-ASCII (variable in length per header/per message) SIP Header is Text-based and variable in length SIP messages *sometimes* have a message body - a SIP message header indicates the type of body - could be text, data, or something about audio, video or something else SIP message body is also variable, but not always present (depending on the Message-type) Example IPv4 SIP Packet format with UDP

6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public SIP—INVITE Message INVITE SIP/2.0 Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bK776asdhds Max-Forwards: 70 To: Bob From: Alice ;tag= Call-ID: CSeq: INVITE Contact: Content-Type: application/sdp Content-Length: Message body goes down here - Content-Length Header indicates one is present RFC 3261

7 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public INVITE (RFC 3261) REGISTER (RFC 3261) SUBSCRIBE and NOTIFY (RFC 3265) UPDATE (RFC 3311) MESSAGE (RFC 3428) PUBLISH* (RFC 3903) Applicable SIP Requests with Location * NOT discussed in SIP Location ID

8 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public Alice SIP INVITE including Location I Bob Location within SIP— carried in header as URI or message body –A UAC can include its location as a message body: Geolocation header, Supported header, geolocation option- tag, Content-Type multipart/mixed INVITE SIP/2.0 Via: SIP/2.0/TCP pc33.atlanta.com ;branch=z9hG4bK77i832k9 Max-Forwards: 70 To: Bob From: Alice ;tag= Call-ID: Geolocation: Supported: geolocation CSeq: INVITE Contact: Accept: application/sdp, application/pidf-xml Content-Type: multipart/mixed; boundary=0a0 Content-Length: 543 INVITE RFC 3261 geolocation (if as a message body) sdp

9 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public Alice SIP INVITE including Location II Bob INVITE RFC a0 Content-Type: application/sdp v=0 o=alice IN IP4 atlanta.com c=IN IP t=0 0 m=audio RTP/AVP 0 a=rtpmap:0 PCMU/8000 Location within SIP— carried in header as URI or message body – A UAC can include its location as a message body: Here’s the SDP

10 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public An SDP message body for voice only SIP Message Body for multimedia v=0 o=alice IN IP4 atlanta.com c=IN IP t=0 0 m=audio RTP/AVP 0 a=rtpmap:0 PCMU/8000 m=video RTP/AVP a=rtpmap:31 H.261/90000 a=rtpmap:34 H.263/ Video - UDP port (51172) for video - Codecs included: H.261, H Audio - UDP port (49172) for audio - Codecs included: G.711 v=0 o=alice IN IP4 atlanta.com c=IN IP t=0 0 m=audio RTP/AVP 0 a=rtpmap:0 PCMU/ Audio - UDP port (49172) to receive RTP - Codecs included: G.711 An SDP message body for voice and video RFC 4566, 3264

11 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public Session Description Protocol (SDP) A session description protocol for multimedia connections Presents a set of parameters for a multimedia session Similar to H.245 in functionality Developed by IETF MMUSIC WG Simple/Flexible Text-based Extensible SIP Offer/Answer Model is RFC 3264 “Lines” below are in order v = protocol version o = owner/creator and session identifier s = session name c = connection information – not required if included in all media k = encryption keys t = time the session is active m = media description and transport address a = (zero or more) media attributes lines RFC 4566, 3264

12 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public --0a0 Content-Type: application/pidf+xml (short form*) Content-ID: N W a0-- Alice SIP INVITE including Location III Bob INVITE Location within SIP— carried in header as URI or message body –A UAC can include its location as a message body: Here’s a short form version of the location message body (long form on next slide) Location in Coordinates Valid size on next slide

13 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public GEOPRIV Geospatial/Coordinate format Based on this GML schema <presence xmlns="urn:ietf:params:xml:ns:pidf" xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10" xmlns:gml="urn:opengis:specification:gml:schema-xsd:feature:v3.0" T09:00:00Z N W no T16:30:00Z To a point, a line, a polygon Provides how location was derived and who is responsible for it –After the fact troubleshooting RFC 4119

14 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public Alice SIP INVITE including Location IV Bob INVITE --0a0 Content-Type: application/pidf+xml (short form*) Content-ID: US Nevada Las Vegas 399 Convention Center Drive LVCC a0-- Location within SIP— carried in header as URI or message body –A UAC can include its location as a message body: Here’s a short form version of the location message body (long form on next slide) Location in civic address form Valid size on next slide

15 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public GEOPRIV civic format Newly defined in the PIDF-LO ID <presence xmlns="urn:ietf:params:xml:ns:pidf" xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10" xmlns:gml="urn:opengis:specification:gml:schema-xsd:feature:v3.0" T09:00:00Z US Las Vegas Convention Center Drive 399 Las Vegas Convention Center no T16:30:00Z Provides how location was derived and who is responsible for it –After the fact troubleshooting Specifies up to 27 fields for civil location RFC 4119

16 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public GEOPRIV civic format Based on US National Emergency Numbering Authority (NENA) XML elements –Except internationalized administrative divisions: A1national subdivisions (state, region, province, prefecture) A2county, parish, gun (JP), district (IN) A3city, township, shi (JP) A4city division, borough, city district, ward, chou (JP) A5neighborhood, block A6street draft-ietf-geopriv-dhcp-civil US Nevada Las Vegas Convention Center Drive 399 LV Convention Center 89109

17 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public Alice SIP INVITE including Location V Bob INVITE SIP/2.0 Via: SIP/2.0/TCP pc33.atlanta.com ;branch=z9hG4bK77i832k9 Max-Forwards: 70 To: Bob From: Alice ;tag= Call-ID: Geolocation: Supported: geolocation CSeq: INVITE Contact: Accept: application/sdp, application/pidf-xml Content-Type: application/sdp Content-Length: 243 INVITE Location within SIP— carried in header as URI or message body –A UAC can include its location as a URI: Geolocation header with URI, Supported header, geolocation option- tag, Content-Type application/sdp

18 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public Alice Bob 200 OK Location within SIP— carried in header as URI or message body –200 OK may contain either form of location delivery (message body or URI) Since Request had appropriate Accept header SIP/ OK Via: SIP/2.0/TCP ;branch=z9hG4bK77i832k9 To: Bob ; tag=a6c85e3 From: Alice ;tag= Call-ID: Geolocation: Supported: geolocation CSeq: INVITE Accept: application/sdp, application/pidf-xml Content-Type: application/sdp Content-Length: 142 (Bob’s SDP here) INVITE SIP Response including Location

19 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public Alice Dereferencing Location URI Bob INVITE (w/Loc URI) Location URI within SIP— carried in header as URI or message body has to be dereferenced to be any good – Location URI recipient (UA or server) will dereference the URI based on the scheme used LIS SUBSCRIBE (w/Loc URI) 200 OK NOTIFY (w/ Location) 200 OK – What happens next is up to what device type did the dereferencing if it’s a UA, it could be done or send its location to UAC if it’s a routing server, the location would be used by LoST next

20 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public INVITE (with Location) 180 Ringing 200 OK ACK INVITE (to URI as R-URI, with Location) LoST (w/ Loc) LoST Answer (w/ PSAP URI) 180 Ringing 200 OK Session Established SIP Routing based on Location of UAC AliceCES.com Proxy LoST Server LV PSAP#1 LV PSAP#2 LV PSAP#3

21 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public Location-based call routing – UA learns its location 36° 13' N 115° 15' W Real-Time LoST Query 36° 13' N 115° 15' W  Las Vegas fire department GPS DHCPBackend DB INVITE sips:psap1.lv... Las Vegas Fire Department Access Point Use of SIP UPDATE Method to update location changes noticed by UAC after call establishment LoST Mapping Server Early LoST Query INVITE sips:usn... or psap2.lv... psap2.lv.clark.nv.us.arpa.sos

22 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public SIP Routing based on UAC’s Location Alice Outbound Proxy SIP Routing based on Location – is not globally unique * “Short form” means not enough room here --0a0 Content-Type: application/sdp v=0 o=alice IN IP4 atlanta.com c=IN IP t=0 0 m=audio RTP/AVP 0 a=rtpmap:0 PCMU/8000 – Location message body could be in the civic format --0a0 Content-Type: application/pidf+xml (short form*) US Las Vegas Convention Center Drive 399 Las Vegas Convention Center N a0-- INVITE w/ SDP and Location INVITE sips:urn:service:sos SIP/2.0 Via: SIP/2.0/TCP pc33.atlanta.com;branch=z9hG4bK74 Max-Forwards: 70 From: Alice ;tag=9fxced76sl To: Call-ID: Geolocation: Supported: geolocation CSeq: INVITE Route: Contact: Content-Type: multipart/mixed; boundary=0a0 Content-Length: 311

23 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public SIP Emergency based on UAC’s Location ESRP PSAP --0a0 Content-Type: application/sdp v=0 o=alice IN IP4 atlanta.com c=IN IP t=0 0 m=audio RTP/AVP 0 a=rtpmap:0 PCMU/ a0 Content-Type: application/pidf+xml (short form*) N W a0-- SIP Routing based on Location – Request-URI based on current LoST Query by ESRP during call – If this “in-call” LoST Query fails, Route header is fallback – Location could be in geo INVITE w/ SDP and Location INVITE sips:psap2.lv.clark.nv.us.arpa.sos SIP/2.0 Via: SIP/2.0/TLS pc33.atlanta.com;branch=z9hG4bK74 Max-Forwards: 70 From: Alice ;tag=9fxced76sl To: Call-ID: Geolocation: Supported: geolocation CSeq: INVITE Route: Contact: Content-Type: multipart/mixed; boundary=0a0 Content-Length: 311 * “Short form” means not enough room here

24 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public Open Issues with ID ABNF determining schemas possible? OPTIONS usage to learn UAS’s location – has to do with Require header usage – probably will kill this idea Location-by-reference allowed? Granular Error Responses in 424