El Lunes, 21 de Septiembre de 2009, Andrei Pelinescu-Onciul escribió:
You miss the usual case in which there is parallel forking and a "wrong" UAS replies 603 "Decline" (instead of a better 480 code). The 603 reply makes the proxy cancelling the parallel branch (still ringing in other branch) and this is, commonly, an undesirable behaviour.
Juha asked initially for voicemail after 6xx (which should work out of the box).
Yes, that's the case of how a "wrong" 6XX from a UAS breaks a so common feature as voicemail.
Just to clarify: in the above case SR will send a CANCEL on all the open branches that have not received a final reply yet. (so the "ringing" should stop on all of them)
And that's the reason why I ask for a disable_6xx_block parameters as it exists in original Kamailio's TM module. Some UA's use 603 to reject a call breaking any parallel forking or serial forking (i.e. voicemail service).
It would be great if disable_6xx_block would be implemented as an optional flag in t_relay() function.
So IMHO, "disable_6xx_block" as it's implemented in Kamailio TM module should also exist in SR as its funcionality is not covered by the current code.
So what you want is a treat 6xxx like a normal reply config option (both parallel forking and cancel branches disabled)?
Yes. It's needed (IMHO) to "fix" a wrong behaviour of UA's rejecting calls with 603 instead of using a more appropriate code as 480 or 403.
BTW here are other possible differences in reply handling:
- received 503 triggers dns failover. If 503 is the final reply, it's replaced with a 500. Also if the blst_503 parameter is on (default off), the source of the 503 reply is blacklisted (using the value in the Retry-After header if present and the blst_503 def_timeout, min_timeout and max_timeout parameters).
- if the final reply is 401 or 407, all the www & proxy auth. headers from all the 401 & 407 replies received on all the branches are aggregated into the final reply (can be turned off with aggregate_challenges).
Doesn't SR's TM module implement these features?
reply priority (negative reply that wins): 6xx 3xx 4xx 5xx
4xx priority: 401, 407, 415, 420, 484 and then the rest (ascending order of their number)
With the exception of 4xx, all other replies in the same class, are sorted according to their number (e.g. 501 wins over 502).
I think it's the correct order.
Regards.