Sipforum SIP & IPv6 discussion slides

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Discussion slides for the SIP forum IPv6 task group conference call 12/12/12 covering issues with SIP DNS, SIP and locating next hop in a dual stack world and issues with Server Based ALG decisions for media paths.

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Sipforum SIP & IPv6 discussion slides

  1. 1. SIP & IPv6 Dual stack issues SIP Forum Conference call 12.12.12 oej@edvina.netonsdag 12 december 12
  2. 2. Agenda • Locating SIP servers in a dual stack world • Happy Eyeballs and SIP • UA media address familiy capabilityonsdag 12 december 12
  3. 3. Living in a dual stack world • RFC 3261 supports either IP4 OR IPv6 • We need to adopt to a dual stack world in order to enable IPv6 migration • RFC 6157 attempts to handle this, but focuses on media • ICE supports dual stack media negotiation (with the IPv6 priority addition) Let’s separate SIP and media sessions (RTP/MSRP/T.38)onsdag 12 december 12
  4. 4. Locating SIP servers RFC 3263 • Clearly says that a SIP device needs to look up IPv4 or IPv6 • We need to replace ”or” with ”and” and apply happy eyeballs to find the next hop. 64 times T1 for failover will NOT be accepted by usersonsdag 12 december 12
  5. 5. I see two issues • Indicating preference of address family in DNS SRV records • Setting up a connection to a dual stack server from a dual stack client • HAPPY EYEBALLS FOR SIP! • Affects STCP,TCP and UDP transportsonsdag 12 december 12
  6. 6. Locating a SIP server • NAPTR doesn’t bother with address family • SRV records point to host names • Hosts can be single stack IPv4, single stack IPv6 or dual stack. • NAPTR can be used to indicate preference of transport. SRV can be used to indicate preference of address family. SIPonsdag 12 december 12
  7. 7. The IPv6 preferred chain ;; Priority Weight Port Target IN SRV 10 3 5060 server1.sipguru.no. IN SRV 10 1 5060 server2.sipguru.no. IN SRV 20 1 5060 server3.sipguru.no. IN SRV 20 2 5060 server4.sipguru.no. _sip._udp.sipguru.no Priority 10 Priority 20 Server1 75% Server2 25% Server3 33% Server4 67% A A AAAA AAAA AAAA AAAA No IPv4 records!onsdag 12 december 12
  8. 8. SIP & Happy eyeballsonsdag 12 december 12
  9. 9. Happy SIP UAs IPv4 IPv4 IPv6 IPv6 • Two network paths to the same service from the same deviceonsdag 12 december 12
  10. 10. Oh no. IPv4 IPv4 IPv6 IPv6 • If the first selected path doesn’t work, what’s the failover time? • This will affect SIP Trunking (SIPconnect)onsdag 12 december 12
  11. 11. Http Solution • Happy Eyeballs • RFC 6555 by Dan Wing • http://ipv6friday.org/blog/2012/04/happyeyeballs/ Needs to be applied to SIP.onsdag 12 december 12
  12. 12. UA capability Discovering support for IPv6 and/or IPv4onsdag 12 december 12
  13. 13. UA IPv6 capability • In some cases, a SIP Server needs to know if a UA is single stack IPv4, single stack IPv6 or dual stack • Signalling address family is not proof enough. A dual stack SIP client may decide to send over IPv4 - which doesn’t reveal the IPv6 capability • This applies to server-based NAT traversal supportonsdag 12 december 12
  14. 14. Hosted RTP proxys • The proxy receives signalling with IPv6 • Checks all the contacts associated with an AOR • How does it detect dual stack clients? • What does it base a decision for adding an IPv4- IPv6-rtpproxy on? • Either dual registrations or a contact capability indication.onsdag 12 december 12
  15. 15. SIP Outbound • Can be used • Two registers with REG-ID over IPv4 and two with the same REG-ID over IPv6 or two registrations with dual contacts • Four flows to maintain • Not very practical • Lack of Outbound implementations • Not a short-term fix with a simple upgrade path for firmwareonsdag 12 december 12
  16. 16. The short term fix • A way to indicate UA media capability for various address families in the contact • This way, server can make policy decisions on media NAT supportonsdag 12 december 12
  17. 17. Suggested priority • Happy eyeballs-fixes for SIP - SIP in a dual stack network • Add dual stack indication in Contact • Make it possible for SIP Forum members to add IPv6 in dual stack mode without adding support requests...onsdag 12 december 12
  18. 18. SIPit 30 • Raleigh-Durham, NC, USA • February 18-22 • Sponsor: Cisco • Will include IPv6 testing! • Online tests will also be available latest in Jan 2013 http://www.sipit.netonsdag 12 december 12
  19. 19. STAY CONNECTED. Add IPv6 to your unified communications platform today. Join us here: twitter.com/sipv6 6 edvina.net/sipv6 facebook.com/sipv ts: Vendor tests at SIPit even Development discussion: www.sipit.net list sip-implementors mailingonsdag 12 december 12
  20. 20. Final message: No,WebRTC will not solve all these issues. ;-)onsdag 12 december 12

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