[SR-Users] getting fragmented packet when adding record-route header

[Alex Balashov]

It sounds like adding the RR header adds just enough payload to push 
the size of your packet over the edge of being too close to the MTU 
boundary.  There's no particular solution except to make the message 
smaller, and/or use a receiving endpoint that supports fragmented SIP 
messages.

On 03/14/2011 03:35 PM, Asgaroth wrote:

> Hi All,
>
> I have a scenario where I have 2 asterisk media servers that, when
> calling a registered sip account, will forward off the invite to a
> location server, who looks up the contact information, then forwards the
> invite off to the proxy that the user registered against (done via the
> path module). This all appears to work perfectly until the us hangs up
> the call. The BYE message does not make it all the way back to the
> originating asterisk media server, it makes it back to the location
> server that looked up the registration information.
>
> To overcome this issue, I add a "Record-Route" header specifying the
> address of the asterisk media server that the request originated from.
> However, when I add the custom header, the Invite shows up as fragmented
> packet my wire-shark trace at the end-user's soft-phone. The call sets
> up properly and when I hang up it looks like the BYE message makes it
> all the way back to the media server, but when it is relayed on the the
> caller, the sip proxy then fails the call with a message too big. If I
> remove the line that adds the record-route header, then all looks fine,
> except that I am unable to tear down calls from sip end-points.
>
> The specific line I'm using to add the header is as follows:
>
> insert_hf("Record-Route:<sip:$si:$sp;lr=on>\r\n","Record-Route");
>
> I do remove this from the route header on in-dialog replies as
> loose-route does not remove the header on the original location server
> as it does not see the route header as local, so I manually remove it.
>
> Has anyone come across this particular issue? I'm using Kamailio 3.1.2.
> Am I going about this is the wrong way? I've been reading the module
> docs for registrar/usrloc/rr/path/textops to see if there is something
> I've missed but cannot see it.
>
> Any tips/suggestions would be greatly appreciated.
>
> Thanks
>
>
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-- 
Alex Balashov - Principal
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