5 Mar
2008
5 Mar
'08
5:52 a.m.
El Wednesday 05 March 2008 11:43:09 Cosimo Fadda escribió:
Hi Iñaki,
my consideration on 404/480 responses comes both from RFC 3261 and from
the RFC 3398 (Integrated Services Digital Network (ISDN) User Part
(ISUP) to Session Initiation Protocol (SIP) Mapping)
About it, I got a very good response in sip-implementators maillist:
"A UAS should not in general know whether it has been called by a gateway
or some other sip device. And so it should not be adjusting its
responses based on the kind of thing it thinks is calling.
The response returned by the UAS should best reflect the condition at
the UAS. The purpose of specs like 3398 is to specify how the sip codes
should be mapped to/from the pstn by gateways, not to specify how other
sip devices should behave."
ISUP Cause value SIP response
---------------- ------------
1 unallocated number 404 Not Found
2 no route to network 404 Not found
3 no route to destination 404 Not found
19 no answer from the user 480 Temporarily unavailable
20 subscriber absent 480 Temporarily unavailable
Anyway it seems that the best practise is to send 404
both cases, but I
prefer to distinguish this two situatations.
I don't know why you think is best to reply 404 in both cases, in fact, if I
reply with 404 then the caller PSTN provider will receive a "unallocated
number" so it will playback an early media message like:
"The number you are calling doesn't exist"
(that's obviously false, it does exist but it's disconnected now).
But finally you use 404 and 480 ;)
Best regards.
--
Iñaki Baz Castillo
ibc(a)in.ilimit.es