Re: Question on loop detection
"Dale Worley" <[email protected]>
| Newsgroups | gmane.ietf.sip |
|---|---|
| Organization | Nortel Networks |
| Message-ID | <[email protected]> |
On Thu, 2009-02-05 at 14:03 +0000, Elwell, John wrote: > It is true this is a merge rather than a loop situation, but the > conditions I describe are conditions for sending a 482 "loop detected". RFC 3261 is correct but not at all clear in this regard. There are *two* error conditions, and RFC 3261 calls both "482 (Loop Detected)". But in reality, there is "482 (Loop Detected)" and "482 (Merged Request)". 482 Merged Request is generated by UASs, as described in section 8.2.2.2, and it is based on noticing that two incoming requests originated as the same UAC request. But the gotcha is that 8.2.2.2 describes UAS behavior, not proxy behavior. 482 Loop Detected is generated by proxies, as described in section 16.3 item 4, and is based on detecting that this request has an "upstream ancestor" request that passed through this same proxy. In regard to a B2BUA acting as an SBC, or a "quasi-proxy" as I like to call it, it needs to apply the loop detection logic, not the merged request logic. Dale _______________________________________________ Sip mailing list https://www.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