7 Nov
2009
7 Nov
'09
8:28 p.m.
El Sábado, 7 de Noviembre de 2009, Juha Heinanen escribió:
Ok, but for non natted TCP dialogs the usage of "alias" (supported by SR) is a
working (and really standarized) solution.
Well, as it's not so complex it makes sense. Just a question: is it easy to
add a *URI* parameter into Contact header?
Yes, right :)
--
Iñaki Baz Castillo <ibc(a)aliax.net>
Of course this
param just exist in case of a NATted client so dealing
manually with it means:
why only nated? this whole thread started as why two tcp connections
are needed to an ua. so the parameter would also be added when request
arrives from non-nated tcp ua so that future requests on this dialog
back to ua could be made to use the existing tcp connection. I would prefer
a new nathelper exported function:
"nat_check_received()"
If ";received" param exists it set $du and returns 1.
If not, $du is not set and returns 0.
i would prefer to leave setting if du to the script. it is not a good
idea to embed too much functionality to functions. so there should be a
function or transformation to remove extract and remove the received
parameter in addition of one that inserts the received parameter. However I
would like to check how it works in this scenario:
UA1 --(NAT)-- Proxy1 ----- Proxy2 --(NAT)-- UA2
- UA1 sends INVITE (private address in headers).
- Proxy1 adds ";received" to Contact URI"
Contact: <sip:ua1@PRIVATE_UA1;received=PUBLIC_UA1>
- Proxy 2 checks NAT. It shouldn't inspect the Contact URI !!! or if so,
it should also take into account the existance of "received" param!!!
(first problem). If not, Proxy2 would also add its own ";received"
param: Contact:
<sip:ua1@PRIVATE_UA1;received=PUBLIC_UA1;received=PROXY1>
i don't see a problem here. proxy should only check nat on requests
that it receives from UAs, not from other proxies, because it should be
other proxies' job to take care of their own UAs.