[Serusers] loose routing of BYE from UDP to TCP

[Klaus Darilion]

I still think this a problem of the caller's client.

As long as there is no transport=tcp parameter in the Contact: header of 
the INVITE ser will use UDP (as the standard says). The transport 
parameter in record route defines how to reach the hop targeted in the 
route header, not the next one.

Thus,  the callee will send the BYE request to ser using UDP. Ser will 
remove its own route headers. Then, ser will route acording the request 
URI in the BYE message (which is the contact URI from the INVITE) and 
will use the transport of the request URI.

klaus

Mark Aiken wrote:
> HI,
> 
> The original RURI does have  but when SER relays to UDP UA it places 
> transport=tcp in the Record-Route but not in the RURI to the UDP UA, 
> which seems correct to me.
> 
> I guess the problem is when using relay_to_udp on an INVITE from a TCP 
> UA, to force SER to act as a TCP to UDP proxy, SER cant handle loose 
> routing new requests in the same dialog back via TCP.
> 
> There seems to be no code in SER to handle this, from the small bits 
> I've looked at anyway. The information is in the rr params that SER 
> added, but SER just ignores the information on loose routed requests 
> when the route is a local one.
> 
> Does anyone know if there is some special trick to get SER to handle 
> TCP<->UDP conversion of loose routed requests? Should the UA be adding 
> the transport=tcp from the rr param to the RURI of the BYE ( I would not 
> think so, since its the 2nd route added by SER anyway, not the topmost).
> 
> For SER to work as a TCP<=>UDP proxy, one needs to "search" for the 
> transport=tcp, somehow be sure its in a local route header, and add the 
> transport=tcp to the uri before calling t_relay, I guess. I haven't 
> tried that yet. All this for loose routed requests.
> 
> This seems like a lot of work in the .cfg file which is better done in 
> rr/tm module.
> 
> I still think I must be doing something wrong as SER should handle this 
> automatically for loose routed requests.
> 
> Is using relay_to_udp not the proper way to force TCP to UDP proxy of an 
> INVITE?
> 
> Mark
> 
> On 9/29/05, *Klaus Darilion* <klaus.mailinglists at pernau.at 
> <mailto:klaus.mailinglists at pernau.at>> wrote:
> 
>     Hi Mark!
> 
>     I do not know it exactly, but I think the important thing is the contact
>     header URI of the INVITE. Does it contain a transport=tcp parameter?
>     Otherwise, ser is correct when using UDP.
> 
>     klaus
> 
>     Mark Aiken wrote:
>      > Hi,
>      >
>      > I'm having problems getting SER to (loose) route requests from UDP to
>      > TCP. I'm not sure if the UA is at fault here or some SER config
>     issue.
>      >
>      > SER receives an INVITE over TCP, record_route() is called and
>     then the
>      > request is relayed via UDP (t_relay_to_udp) to the UA. The
>      > INVITE relayed to the UDP UA now has 2 Record-Route headers added by
>      > SER. One has the transport=tcp  parameter.
>      >
>      > Record-Route: <sip: xx.xx.xx.xx;r2=on;ftag=xyz;lr=on>
>      > Record-Route: <sip:xx.xx.xx.xx;transport=tcp;r2=on;ftag=xyz>
>      >
>      > When the UA sends the BYE to SER, it has the 2 Route headers like
>     so (on
>      > a single line):
>      >
>      > Route:
>      >
>     <sip:xx.xx.xx.xx;r2=on;ftag=xyz;lr=on>,<sip:xx.xx.xx.xx;transport=tcp;r2=on;ftag=xyz;lr=on>
>      >
>      > The SER script simply calls t_relay() in the loose_route section
>     of the
>      > script.
>      >
>      > I expected t_relay() to relay the BYE via TCP, since the Route header
>      > has transport=tcp, but it sends the BYE via UDP instead.
>      >
>      > Anyone seen this problem before? Do I need to check for
>     transport=tcp
>      > and call t_relay_to_tcp, rather than using t_relay after
>     loose_route()?
>      >
>      > Mark
>      >
>      >
>      >
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