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List:       serusers
Subject:    Re: [SR-Users] CSeq values in dialog OPTIONS keepalives
From:       Alex Balashov <abalashov () evaristesys ! com>
Date:       2020-01-24 23:41:34
Message-ID: 20200124234134.GA696 () typhoon
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Hi,

How is the determination of CSeq for dialog-spoofed BYEs made?

Thanks,

-- Alex

On Fri, Jan 03, 2020 at 04:16:51PM +0100, Daniel-Constantin Mierla wrote:

> Hello,
> when the call is established, there is one request (the INVITE) from caller
> to callee. Then the ACK also from caller to callee. But there is no request
> from callee to caller at that moment. Each side is using its own cseq
> value, the callee doesn't have to use the latest cseq from caller plus one
> when it sends a request (like a re-INVITE or the BYE). In practice the cseq
> 0 is not usually used by an UA, so that's why the keepalive for that
> direction is using it.
> 
> Cheers,
> Daniel
> 
> On Thu, Jan 2, 2020 at 10:07 PM Alex Balashov <abalashov@evaristesys.com>
> wrote:
> 
> > On Thu, Jan 02, 2020 at 09:26:23PM +0100, Daniel-Constantin Mierla wrote:
> >
> > > the cseq 0 is because in that direction was no request sent
> > > end-to-end.
> >
> > Also, sorry, but I didn't quite understand this.
> >
> > --
> > Alex Balashov | Principal | Evariste Systems LLC
> >
> > Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
> > Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
> >
> > _______________________________________________
> > Kamailio (SER) - Users Mailing List
> > sr-users@lists.kamailio.org
> > https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
> >
> 
> 
> -- 
> Daniel-Constantin Mierla - https://www.asipto.com
> https://twitter.com/miconda - https://www.linkedin.com/in/miconda
> Kamailio Advanced Training - https://www.asipto.com/u/kat

> _______________________________________________
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-- 
Alex Balashov | Principal | Evariste Systems LLC

Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) 
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/

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