Hi, please correct me if I'm wrong but Outbound/GRUU has a design "issue" when the TCP connection is closed (i.e. SIP outbound proxy disconnection). Scenario:
alice ------ OB-1 ------ PROXY/REGISTRAR ------ OB-2 ------ bob - Both alice and bob are SIP TCP clients (Outbound/GRUU capable) connected to OB-1 (Outbound-Proxy-1) and OB-2 respectively. - Both alice and bob are registered in PROXY/REGISTRAR through their outbound proxies using Path. - alice calls bob through OB-1 which routes the INVITE to the PROXY which obtains the location of bob and routes the INVITE to OB-2. OB-2 routes it to bob based on the Outbound identifier in the Route added by the PROXY/REGISTRAR. - The INVITE sent by alice has alice's public GRUU as Contact URI. - bob sends some in-dialog request to alice (i.e. re-INVITE) which is routed based on Outbound rules (Outbound identifier in Route headers) by OB-2, PROXY/REGISTRAR and OB-1. - Later OB-1 is restarted so the connection with alice is lost. At this point alice re-registers using some +sip.instance and reg-id. The REGISTRAR replaces its binding. *** ISSUE: *** - If alice sends an in-dialog request to bob (i.e. re-INVITE) OB-1 won't change the INVITE route set (of course) so the Outbound identifier of alice's connection will still identifying the *PREVIOUS* alice's connection. - So later bob sends a new in-dialog request to alice (i.e. BYE). When the request arrives to OB-1, that proxy will realize that the Outbound identifier belongs to an already closed connection so will reply 430 "Flow Failed" to PROXY/REGISTRAR. And PROXY/REGISTRAR cannot perform "serial forking" since it's just an in-dialog request and therefore it SHOULD NOT examine the Request URI (which contains the public GRUU of alice). So, we have a hyper cool and complex specification/implementation of Outbound, Path and GRUU but still we cannot re-use an existing SIP dialog after a simple TCP disconnection? in 2012? Ouchhh..... Hope I miss something. I'd appreciate any suggestion on this subject. Thanks a lot. -- Iñaki Baz Castillo <[email protected]> _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
