NAT is not yet standardised. Based upon the implementation there are classification of 4 types of NAT.
When you speak of NAT. It is not just one endpoint making the decision, it also need to know about the other NAT endpoint. Even if one NAT is in symmetric and other is not symmetric you will be still to route the rtp data directly. Regards, Kannaiyan ----- Original Message ----- From: "Ivar" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, April 18, 2007 1:49 PM Subject: [Sip-implementors] SIP and NAT > Hi, > > I have long time messed with SIP and NAT, funny no docs out what say if > you have for example symmetric NAT SIP won't work. > > But now middle of completing STUN client i see how each NAT works. > > For normal operation of SIP there must be: public internet,full cone > nat,restricted cone nat. > symmetric and port restricted won't work - only is b2bua. > > Does that mean b2bua is only SIP proxy what can be used in real life, i > looked most routers are port restricted or symmetric ? > > What problem is with port restricted for example: (UA2 is port restricted) > UA1(invite) -> Proxy -> UA2 All ok > UA1(ACK) ------------>UA2 > ACK is sent directly but UA2 never allows data from UA1 because UA2 > haven't sent data to UA1. > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
