The UAC should decide the IP version prior to sending. There are a few IETF RFC that discusses the IPv4/IPv6 and dual stack challenges and implementation considerations.
You may want to read this RFC 6555, RFC 6157 as a start. Typically if you have IP address as the UAS, then it is fairly straightforward. In case you have FQDN, or SRV query you have to take the decision of populating via header until after you get the resolved responses. You also have to deal with media that may potentially use different IP version than the signaling IP version. Thanks, Neel. -----Original Message----- From: sip-implementors-boun...@lists.cs.columbia.edu [mailto:sip-implementors-boun...@lists.cs.columbia.edu] On Behalf Of Harshith Mulky Sent: Sunday, November 29, 2015 10:39 PM To: Iñaki Baz Castillo <i...@aliax.net> Cc: sip-implementors@lists.cs.columbia.edu Subject: Re: [Sip-implementors] How is a VIA added as either a IPV4 address or IP6 Address by a Proxy/B2BUA If the B2BUA is supporting both IPV4 or IPV6 address, which IP does the B2BUA place, its IPV4 or IPV6 address? ________________________________________ From: Iñaki Baz Castillo <i...@aliax.net> Sent: Friday, November 27, 2015 6:04 PM To: Harshith Mulky Cc: sip-implementors@lists.cs.columbia.edu Subject: Re: [Sip-implementors] How is a VIA added as either a IPV4 address or IP6 Address by a Proxy/B2BUA 2015-11-27 13:23 GMT+01:00 Harshith Mulky <harshith.mu...@outlook.com>: > How does a B2BUA/Proxy know which IP Preference(IP4/IP6) need to be > added in VIA when reaching a Server(UAS) This question makes no sense. The IP in the Via header must match the local IP from which the UA/B2BUA/Proxy sends the SIP request, nothing else. -- Iñaki Baz Castillo <i...@aliax.net> _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
