Hello,
On 11/13/10 3:09 PM, Iñaki Baz Castillo wrote:
2010/11/12 Daniel-Constantin Mierla<mico...@gmail.com>:
The idea is to receive the 486 from the carrier and not send the
INVITE SDP back to the carrier, this is causing the carrier to send a
482 loop detected.
First, if you create a new branch and send to same SIP gateway and you get
loop detected, then the gateway is broken. It does not see that there is a
different branch value in the top Via header.
Hi Daniel, the 482 reply is correct:
I expected the r-uri changes as well (serial forking). In regard to this
similar case, there is a difference between loop detection and spirals,
maybe sorted out in a follow-up rfc.
Cheers,
Daniel
----------------------------------------------------------------------------------
RFC 3261 - 8.2.2.2 Merged Requests
If the request has no tag in the To header field, the UAS core MUST
check the request against ongoing transactions. If the From tag,
Call-ID, and CSeq exactly match those associated with an ongoing
transaction, but the request does not match that transaction (based
on the matching rules in Section 17.2.3), the UAS core SHOULD
generate a 482 (Loop Detected) response and pass it to the server
transaction.
The same request has arrived at the UAS more than once, following
different paths, most likely due to forking. The UAS processes
the first such request received and responds with a 482 (Loop
Detected) to the rest of them.
----------------------------------------------------------------------------------
This is exactly the case the user is experimenting: the INVITE arrives
twice to the same server, with same From tag, Call-ID and CSeq, but
different branch/transaction. So 482 is the correct response.
Regards.
--
Daniel-Constantin Mierla
http://www.asipto.com
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