Vivek, I think the issue you talked about is how to identify which REGISTER the 200(register) responds to, I think RFC3261 sec 17.1.3 Matching Responses to Client Transactions has already given the solution.
Another question is if you give REGISTRA the internal ip addr, how would you expect the incoming request go? i.e, which destination ip addr would incoming INVITE ueses? the internal ip addr? -Rockson ________________________________ From: Vivek Batra [mailto:[EMAIL PROTECTED] Sent: Friday, June 27, 2008 7:36 PM To: Rockson Li (zhengyli); 'Scott Lawrence'; sip-implementors@lists.cs.columbia.edu Subject: RE: [Sip-implementors] SIP client registers from multiple locationsand all location are behind the NAT I clarify the same, UA1 NAT1 REGISTRAR ----------------REG1-----------------> src ip: 10.0.0.1 port 5060 contact:10.0.0.1:5060 ----------------REG2-----------------> src ip: 59.162.252.82 port 8888 contact: 10.0.0.1:5060 In the above scenario, UA1 is behind the NAT and 'src ip' is referring as Network Layer address. When REGISTER passes through NAT (L3), contact remains the same. Due to symmetric response implementation on REGISTRAR side, all the responses are sent back only to '59.162.252.82:8888'. UA2 NAT2 REGISTRAR -----------REG3----------> src ip: 10.0.0.1 port 5060 contact:10.0.0.1:5060 ----------------REG4-----------------> src ip: 199.100.100.100 port 9999 contact: 10.0.0.1:5060 Now, in above scenario which is different LAN network from scenerio1, UA2 has assigned the same IP:Port as UA1. UA2 sends the REG request using same SIP-Id/ Authentication credentials as used by UA1. REG message passes through NAT (L3) and contact remains the same. Now, REGISTRAR has two contacts binding for this user. When REGISTRAR sends 200 OK for REGISTER message to UA2, this 200 OK will include both the bindings of user and both the contact bindings will have same value viz '10.0.0.1:5060'. Now how the UA2 would identify its own binding to get the expiry timer allocated by registrar to UA2. --Vivek _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
