5 Jul
2011
5 Jul
'11
7:04 p.m.
2011/7/5 Jan Janak <jan(a)ryngle.com>om>:
Yes, I'm not suggesting to change it, just wanted to open a discussion
about it :)
I agree. sips schema is a pain. There is a RFC (5630) trying to
clarify it (as 3261 says nothing clear) and still here are a lot of
doubts about it.
Maybe it's just better to continue with sip and transport=tls in
Record-Route, but another approach could be sips and transport=tls (it
would satisfy devices expecting sips and devices expecting tls
transport).
Cheers.
--
Iñaki Baz Castillo
<ibc(a)aliax.net>
So what is the difference then? How is a Route header
with sips scheme
different from a Route header with the transport=tls parameter? Is the
proxy server supposed to treat Route headers with sips differently
than Route headers with sip;transport=tls?
No, the only difference is that transport=tls is deprecated and
""""maybe"""" some devices don't understand
;transport=tls.
But my original question was related to the
Route/Record-Route header.
There the proxy records the particular transport mechanism that was
used when the dialog was being established. So if the INVITE was
received over TLS, it would contain ;transport=tls in the Route
header.
You mentioned that the Route header should rather contain sips scheme
if the scheme of the Request-URI was sips. And I don't understand why.
Maybe you're right, but I don't see what difference that would make at
the moment.
Within a hop, sip:IP;transport=tls and sips:IP;transport=tcp seems to
mean exactly the same. It just occurs that sips is preferred by RFC's
and "tls" seems to be deprecated.
But anyway, in
other thread in sip-implementors I got the conclussion
that RFC 3261 deprecates sips schema with transport=tls, but says
nothing about sip schema with transport=tls (in fact, "tls" is still a
valid transport according to the BNF grammar). So, I don't say that
current sip-router behavior is wrong, but I think it would be more
"ellegant" if it would use sips URI and ;transport=tcp.
Elegant is a subjective and it hardly justifies such change, we need
more hard evidence supporting such change. NOTE: In fact,
some existing clients (as the widely extended PJSIP)
would fail if the Record-Route contains sips+transport=tcp as I've
reported today:
http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/2011-July/013102.html
This is because PJSIP does not understand at all the meaning of a sips
schema (ugly in a so widely deployed SIP stack).
One can hardly blame them, I don't understand sips either ;-).