[Kamailio-Users] [SR-Users] force_rtp_proxy() vis-a-vis BYE

[Klaus Darilion]

Iñaki Baz Castillo schrieb:
> 2009/7/8 Klaus Darilion <klaus.mailinglists at pernau.at>:
>>>  From what seems here, definitely does not deal with PATH extension.
>> I think the concept of nat_traversal correctly is focused on using outbound
>> proxies - e.g. you have several outbound proxies (multiple SRV or A records)
>> which relay the signaling to the core proxies (registrars, presence servers
>> ...).
>>
>> In such a setup there is no need for PATH support as the nat_traversal will
>> be done on the outbound proxy.
> 
> I don't understand this. PATH is required when a registration is done
> through an outbound proxy, so the registrar routes request for that
> AoR using also through the outbound proxy (the RURI is the Contact of
> the REGISTER but the request is sent to the OBP.

E.g.:  client <--->OBP<---->Registrar

If the Registrar does the NAT traversal, the NAT traversal mechanism 
must take into account the PATH, that means either:

- send OPTION requests to the client using a pre loaded route via the OBP
- send OPTION requests or emtpy CRLF packets with spoofed source IP (the 
IP of the OBP)

If the OBP does the NAT traversal, the NAT traversal mechanism need not 
take care about PATH because there is no SIP proxy between the client 
and the OBP.

regards
klaus