IETF63_voipeer_CableLabs_PacketCable_CMSS_-_Inter-domain_SIP_Requirementsfor_IETF_VoIP_Peering_BOF-final

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IETF63_voipeer_CableLabs_PacketCable_CMSS_-_Inter-domain_SIP_Requirementsfor_IETF_VoIP_Peering_BOF-final Powered By Docstoc
					   IETF VoIP Peering BOF:
  Input on Inter-domain SIP
Requirements for VoIP Peering

         Jean-François Mulé
             CableLabs
         jfm@cablelabs.com


                                1
               Agenda
• Overview of CableLabs® PacketCable™
  CMSS* Specification
• Examples of Use Cases
• Lessons learned




                                                                             2
                         *CMSS = Call Management Server Signaling Specification
    CableLabs PacketCable CMSS Overview
         CMSS = IETF SIP + IETF SIP Extensions
•   PacketCable CMSS
     – CMSS is the Call Management Server Signaling Specification
     – Part of PacketCable 1.5, version I01 available publicly at
         http://www.packetcable.com/specifications/specifications15.html
          http://www.packetcable.com/downloads/specs/PKT-SP-CMSS1.5-I01-050128.pdf

•   CMSS designed to provide vendor requirements for intra-domain and inter-
    domain SIP signaling for VoIP applications
     – CMSS was authored by many vendors involved in IETF based on original service
       requirements provided by cable MSOs

•   CMSS comprises IETF Basic-SIP RFC 3261, plus the following IETF SIP
    Extensions:
     –   SIP Extension requirements to support quality-of-service
            •   Network Resource Reservation pre-conditions
            •   Reliability of Provisional Responses (PRACK)
     –   Extensions to support Regulatory & Billing Requirements (Electronic Surveillance, E911,
         malicious call trace)
            •   Asserted Identity in Trusted Networks (P-Asserted-Identity header)
            •   DCS proxy-proxy for event accounting, electronic surveillance, & operator services
            •   Uniform Resource Identifiers for telephone calls


                                                                                                     3
    CableLabs PacketCable CMSS Overview

•   Extensions to support Feature Control:
     – Session parameter updates (UPDATE) for some call features, codec changes,
       FAX/modem, …
     – SIP REFER and Replaces header for advanced call features; e.g. call transfer,
       call park, conference
     – SIP SUBSCRIBE/NOTIFY to enable Message Waiting Indication and other “non-
       call” related features

                     Administrative Domain 1                         Administrative Domain 2


                                                        SIP                               `
                           MSO A                                               MSO B
                                          CMS                       CMS
                       `   Zone 1                     CMSS                     Zone 3

                                                                                         PSTN
                                                                                        Gateway
                                                                                                  PSTN

                                SIP                   Managed
                                                    IP Backbone
                              CMSS

                                      `                 SIP          SIP
                                                                    CMS
                                                                               MSO C
                           MSO A                                    Servers    Zone 4         `
                                          CMS         CMSS
                           Zone 2
                                                                                         PSTN
                       `                                                                Gateway
                                                                                                  PSTN
                                     PSTN
                                    Gateway
                                                   PSTN
                                                                     Administrative Domain 3

                                                                                                         4
                                                PacketCable 1.5 and SIP/CMSS
       CableLabs PacketCable CMSS Overview
       IETF SIP Extensions – Partial List of RFC requirements


 IETF RFC                                                Name                                                      Nickname
RFC 3261       SIP                                                                                             SIP
RFC 3262       Reliability of Provisional Responses in SIP (PRACK)                                             PRACK
RFC 3265       SIP-Specific Event Notification                                                                 Event Notification
RFC 3311       SIP UPDATE Method                                                                               UPDATE
RFC 3312       Integration of Resource Management and SIP for IP Telephony                                     precondition
RFC 3323       A Privacy Mechanism for the Session Initiation Protocol                                         privacy
RFC 3325       Private Extensions to SIP for Asserted Identity within Trusted Networks                         p-asserted-ID
RFC 3420       Internet Media Types message/sip and message/sipfrag                                            sipfrag
RFC 3603       Private SIP Proxy-to-Proxy Extensions for Supporting the PacketCable DCS                        DCS
RFC 3515       SIP REFER Method                                                                                REFER
RFC 3891       SIP Replaces Header                                                                             Replaces
RFC 2806/3966 URLs for Telephone Calls                                                                         tel URL
Internet-Draft Tel URI to support Number Portability                                                           tel extensions
RFC 3842       A Message Summary and Message Waiting Indication Event Package for SIP                          mwi
         etc…       this list is not exhaustive and will evolve based on service requirements
                                                  and IETF updates
               (note: current CMSS may still point to some IDs that have become RFCs since last publication)


                                                                                                                             5
          Examples of CMSS Use Cases
            Why we need PacketCable CMSS [or something like it]

1.    Intra-domain, Inter-zone
      One administrative domain with multiple CMSes or SIP servers
     –     Scenario-1.1: Flat-rate on-net call
     –     Scenario-1.2: Call trace with number privacy
     –     Scenario-1.3: Measured rate call
2.    SIP carrier-to-PSTN
      One administrative domain, CMS “on-net”  MGC off-net
     –     Scenario-2.1: Carrier selection: caller dials CIC
     –     Scenario-2.2: Called number ported
     –     Scenario-2.3: E911 with Privacy
3.    Inter-SIP carriers („trusted‟)
      Multiple administrative domains
     –      Scenario-3.1: Measured rate call
4.    Inter-SIP carriers („non-trusted‟)
     –     Scenario-4.1: Caller dials CIC & ported number
     –     Scenario-4.2: E911
5.    SIP Applications
      Voicemails, etc.
     –     Scenario-5.1: Visual MWI
     –     Scenario-5.2: 3-way conference




                                                                     6
           E.g. Scenario-1.2:
    Call-Trace with Number Privacy
            CMS1                                            CMS2


MTA-1                                                              MTA-2

 Off-hook      [1]INVITE
               From: “anonymous” sip:anonymous@anonymous.invalid
               P-Asserted-ID: “anonymous” tel:+2125551212
               Privacy: id critical
               Proxy-Require: Privacy

                   Remainder of flow same as Scenario-1.1
• Caller ID is masked in the From: field so that it is not
  displayed
• Caller ID is stored in the P-Asserted-ID field for routing
  purposes (911, call trace), and other call features
  (block), etc.
                                                                           7
                          Extension Matrix
               Extension




                                            Conditions
                                            Pre-


                                                         PRACK


                                                                 Tel-URI


                                                                           P-DCS

                                                                                   ID
                                                                                   P-Asserted-


                                                                                                 UPDATE


                                                                                                           REFER

                                                                                                                   Header
                                                                                                                   Replaces
                                                                                                                              Notify
                                                                                                                              Event


                                                                                                                                           Visual MWI
               Scenario


Intra-         Flat-rate on-net call                                                                   The choice of
domain,        Call-Trace with number                                                                 standard, private
Inter-Zone     privacy                                                                                    and future IETF SIP
                                                                                                          extension(s) for
               Measured rate call                                                                     each service
SIP carrier-   Carrier Selection – caller                                                             scenario can be
to-PSTN        dials CIC                                                                                  largely debated.
               Called number ported                                                                   This is just an
               E911 with Privacy                                                                     example, one view
                                                                                                          on how we meet
Inter-carrier  Measured rate call                                                            
                                                                                                          requirements.
(trusted)                                                                                                 This is where the
Inter-carrier Caller dials CIC & ported                                                               difficulties of Inter-
                                                                                                          domain SIP arise in
(non trusted) number                                                                                      VoIP peering.
              E911                                                                           
SIP Apps       Visual MWI                                                                                                                 
               3-way Conference                                                                                                    8
                        Lessons Learned
•       VoIP SIP peering today
    •         No common way of addressing basic VoIP SIP requirements among SIP
              service providers
          •       Issues not limited to service provider model and not necessarily due to “walled
                  garden approach”: end-user model also impacted (SIP UA vendors)
          •       Border elements seen as the current “patching solutions” for SIP „protocol
                  normalization‟
          •       Difficult definition of trust boundaries between providers
    •         Various levels of support for common IETF SIP extensions (PRACK, p-
              asserted-id, UPDATE, etc.) but IETF SIP private extensions perceived as
              industry specific (e.g. RFC3603)
•       CMSS Specification Enhancements:
        SIP Implementers should
    •         Build standard-based mechanisms for negotiating SIP extensions (Supported,
              Allow, Require headers)
    •         Provide configuration means for end-users and/or providers to be capable of
              configuring the mandatory/optional SIP extensions advertised in the SIP
              signaling and provide means for enforcing SIP signaling “policies”

                                                                                                    9
      Q&A

Feedback welcome




                   10

				
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