[Serusers] chosing the right Via header in multihomed SER instance - sr-users

25 Jan 2005


      Hi,
I have received this and I don't know what's wrong, maybe any guru can
help:
Samuel.
Unclassified.
...
In my test lab i found that SER adds a wrong VIA header. 
The scenario is like this:
phone1 ---- SER_1 ----- SER_2 ---- phone2
phone 1 is registered at SER_1 (it's proxy)
phone 2 is registered at SER_2  (it's proxy)
When phone2 wants to call phone1, it sends the invite to SER2. SER2
checks in their local database for phone1, and does not find it. SER2
forwards the invite message on (using >multicast address 230.x.x.x).
SER1 is listening on two addresses: unicast one (192.y.y.y) and
multicast one (230.x.x.x). He receives the invite from the multicast
address, checks for >phone1 and finds it registered in his local
database. SER1 relays (t_relay) to phone one. Here is where the error is
introduced: SER1 adds a VIA header to the message relayed to >phone1,
but instead of this header containing the SER1_unicast address, it
contains the multicast one. This makes phone1 to then reply and send
messages to the multicast >address (taken from the via in the invite),
instead of following the recourd-route setting (for the OK message it
does follow it, not for ACK or 1xx).
...
Any idea on what is wrong? 
I read in the code something about support for multi-homed proxies, as
well as a parameter called default_global_address. Might these help?
...
Thanks in advance!
Cesc