Re: [OpenSER-Users] appending into Via header - sr-users

16 Jun 2008

Hi,
Ok this is what I am planning to do.
I am using Cisco 5350 as SBC after my Openser proxy to relay calls. In cisco there is a
good option of matching carrier-ids and relay calls to appropriate carriers.
Cisco looks at the x-route-tag parameter or tsp parameter which is appended to the Via
header to match the carrier-id. So basically Cisco searches for it in the Via header.
Thus I need to put this x-route-tag or tsp parameter in the Via header so that Cisco will
parse the carrier-id and process calls according to the carrier-id defined.
The x-route-tag= or tsp= values will be fetched from the database which will depend on the
called number.
Now I tried the following and it works but it gets messed up somewhere near the rport
parameter in the Via header and the return responses goes to improper ports.
subst('/^Via: .*/Via: $(hdr(Via));tsp=1234\r\n/');
The initial INVITE that I get from the UA is similar to the following (i have pasted only
the first two lines as the relevant Via headers are present there):
INVITE sip:7050@192.168.2.125 SIP/2.0..Via: SIP/2.0/UDP
192.168.2.21:6221;branch=z9hG4bK-d87543-b9072d1e713a491a-1--d87543-;rport..Max-Forwards:
70..Contact: <sip:1234@192.168.2.21:6221>..To: <sip:7050@192.168.2.125>..
When this INVITE is forwarded to my Cisco it goes as follows:
INVITE sip:7050@192.168.2.252 SIP/2.0..Record-Route:
<sip:192.168.2.125;lr=on;ftag=cc40082e>..Via: SIP/2.0/UDP
192.168.2.21:6221;branch=z9hG4bK-d87543-b9072d1e713a491a-1--d87543-;rport;tsp=1111..Via:
SIP/2.0/UDP 192.168.2.125;branch=z9hG4bKd909.4996e851.0..;rport=6221.Max-Forwards:
69..Contact: <sip:1234@192.168.2.21:6221>..To: <sip:7050@192.168.2.125>..
Now if you take a look at the rport parameter above it is completely messed up. The rport
becomes a new header. 
Can someone help me to overcome this problem.
Thanks in advance.
-- Jayesh

----- Original Message ----
From: Henning Westerholt &lt;henning.westerholt(a)1und1.de&gt;
To: Jayesh Nambiar &lt;voip_freak(a)yahoo.co.in&gt;
Cc: users(a)lists.openser.org
Sent: Monday, 16 June, 2008 5:38:23 PM
Subject: Re: [OpenSER-Users] appending into Via header

On Monday 16 June 2008, Jayesh Nambiar wrote:
...
  I do not want it to add two times. I have explained as
to where I want to
 add it in the Via header. I dont want to add it twice in the message. I
 know I can easily add a new header but that does not meet my requirement. I
 want it to be appended to the Via header that Openser creates while sending
 the call to the PSTN gateway. To be precise, the format has to be like:
 Via:
 SIP/2.0/UDP 192.168.2.125;branch=z9hG4bK7e7c.877b4352;x-route-tag="cid:1234
" where 192.168.2..125 is my openser and x-route-tag is what I want to
 append in the Via header. Thanks again for your help. 
Hi Jayesh,

i don't know anything about your configuration, so i can't help you that much 
with regards to your requirements, sorry. Please read the documentation for 
the textops module. Perhaps the "subst" function is something you could use? 
Its possible to alter existing header content with it.

Henning

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