[Serusers] loop call with asterisk

[Richard]

I seem to be able to solve this problem by looking at ruri for the request.
Besides checking the callid, I also compare the current ruri and existing
ruri to see if it is indeed the same call.

Thanks for leading me the right direction.

Richard


> -----Original Message-----
> From: Bogdan-Andrei IANCU [mailto:iancu at fokus.fraunhofer.de]
> Sent: Tuesday, October 05, 2004 11:08 PM
> To: Richard
> Cc: serusers at lists.iptel.org
> Subject: Re: [Serusers] loop call with asterisk
> 
> Hi Richard,
> 
> I guess it's a very thin line between a loop and a spiral. They are very
> similar (even impossible to tell the difference from SIP point of view),
> but first is harmful and the second useful :-).
> I haven't went through the RFC, but IMHO is tricky for UAS detect
> properly a loop - I guess that's way everybody relies on MAX_FORWARD to
> end potential loops.
> So, depends a lot of what *  consider a loop (how exactly does this) -
> because, as you said, all important hdrs are the same. Btw, is at least
> RURI changing between  outgoing and returning call ( on *) ?
> The worst solution will be insert a very simple B2BUA in the middle to
> change at least some tags. But is ugly :-(
> 
> regards,
> Bogdan
> 
> 
> Richard wrote:
> 
> >Hi,
> >
> >I am trying to use * as a PSTN gateway. When a call comes in from PSTN,
> it
> >is forwarded to ser. If for some reason (e.g. call being forwarded back
> to
> >PSTN), ser will just do a record route and send it back to *. When * gets
> >this call, it thinks it is a loop and drop the call. I know that this
> >question has been raised before. I'd like to see, just from sip
> respective,
> >what's the theoretical way to solve it? Since all major fields are the
> same,
> >e.g. fromuri, touri, cseq, callid, what is the right way to detect loop
> in
> >SIP in this case? Btw, cisco router doesn't have this problem.
> >
> >Thanks,
> >Richard
> >
> >
> >
> >
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> >