Adam's summary is the best of such that I have seen. One could only add regarding NAT traversal, in P2P SIP networks many folks are convinced that a large number of peers behind p2p-friendly NAT can act as STUN and media relay servers for other peers and for p2p clients as well.
This has however yet to be proven from deployment statistics on the Internet, but for what it's worth, Skype has proven such an approach can work. Henry -----Original Message----- From: Adam Roach [mailto:[EMAIL PROTECTED] Sent: Tuesday, October 16, 2007 11:38 AM To: Pars Mutaf Cc: [email protected] Subject: Re: [Sip] SIP trapezoid (was Re: IETF solution forpairing cellularhosts) Pars Mutaf wrote: > I have asked a SIP question (I think this is the right place). Please > answer > my question about SIP trapezoid, or if you don't know, that's OK. Nothing mandates a trapezoid. That kind of deployment can be useful for certain architectures, but SIP can work just fine without it. A trapezoid deployment can be useful for certain things; three come to mind immediately: * Rendezvous (although technically all you need for rendezvous is a triangle, not a trapezoid). Note that there are other potential solutions here, such as fixed IP addresses (including mobile IP), dynamic DNS, DHTs, and HIP. * NAT and firewall traversal (using the outbound extensions). This is only necessary if you're behind a NAT or a Firewall. Even then, there may be other solutions depending on what you are trying to accomplish, such as STUN/TURN, SOCKS, VPNs, uPNP, etc. * Network provided services. Most services can be successfully implemented in the terminal, but there seems to be a trend of pushing most services into the network (probably because it's difficult to charge people recurring fees for something their phone knows how to do). If you end up with users who have network-provided services, then you'll need to go through their servers. If you don't need any of these things, then a trapezoid is unnecessary. /a _______________________________________________ Sip mailing list https://www1.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [EMAIL PROTECTED] for questions on current sip Use [EMAIL PROTECTED] for new developments on the application of sip _______________________________________________ Sip mailing list https://www1.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [EMAIL PROTECTED] for questions on current sip Use [EMAIL PROTECTED] for new developments on the application of sip
