[OpenSER-Users] Failover using NAPTR/SRV

[Bogdan-Andrei Iancu]

Douglas,

Douglas Garstang wrote:
> Ok, so rfc3263 defines what the user agent should do when a 503 reply, 
> or no reply is received.
> What about the rest of the possible SIP replies?
the RFC defines the standard ways to detect SIP failures (transport and 
signalling) - both the detection and failure should be done accordingly.
>
> We use several different ITSP's. I just checked the logs for our last 
> 50,000 calls from all of them and there was a total of 19 different 
> replies received.
>
> They are:
> 200,400,401,403,404,408,410,480,484,486,487,488,500,501,502,503,504,603
>
yes, but not all this replies indicate a failure of the GW (case which 
interests you) - many negative replies indicates an unsuccessful call 
setups and has nothing to do with the failure of the GW itself.
This was the main RFC idea - how do identify a failure of the SIP point 
and not the failure of the call.
> Some of these can occur under normal conditions, 486 is busy for 
> example, or 487 is generated by a CANCEL.
correct - also probably 408 timeout.
>
> What about the rest? Most of the rest can be classified as error 
> conditions. Are you saying that if another error condition besides 503 
> is received that you don't do failover? Why?
Again, are these errors, call errors or GW permanent errors (which will 
make you want to disable routing to that GW) ? Because it is the GW duty 
to correclty report the failure and the nature of the failure.

Have you tried to see what are the errors behind the negative replies 
you get from GW??

Regards,
Bogdan
>
> Douglas.
>
>
>
> ----- Original Message ----
> From: Bogdan-Andrei Iancu <bogdan at voice-system.ro>
> To: Douglas Garstang <dougmig33 at yahoo.com>; users openser.org 
> <users at openser.org>
> Sent: Friday, February 15, 2008 5:56:45 AM
> Subject: Re: [OpenSER-Users] Failover using NAPTR/SRV
>
> Of course it is.....by IETF  - see RFC3263.
>
> 4.3 Details of RFC 2782 Process
>
>
> Regards,
> Bogdan
>
>
> Douglas Garstang wrote:
> > Well that's weird. What do you mean by 'fail'? I thought dns_blacklist
> > was used when a 503 response was received? What if the connection
> > times out? What if another negative reply is received? Is this stuff
> > documented anywhere?
> >
> > ----- Original Message ----
> > From: Bogdan-Andrei Iancu <bogdan at voice-system.ro 
> <mailto:bogdan at voice-system.ro>>
> > To: Tobias Lindgren <tobias.lindgren at ip-only.se 
> <mailto:tobias.lindgren at ip-only.se>>
> > Cc: users at openser.org <mailto:users at openser.org>
> > Sent: Thursday, February 14, 2008 3:25:33 AM
> > Subject: Re: [OpenSER-Users] Failover using NAPTR/SRV
> >
> > Hi Tobias,
> >
> > if you have "dns_backlist=yes" in your config, if one of the destination
> > server fails (according to SIP definition), it's IP will be added to a
> > temporary blacklist (for 4 minutes) and not used. So, openser should do
> > dns-based failover and use the next entry provided by NAPTR/SRV/A 
> lookup.
> >
> > Regards,
> > Bogdan
> >
> > Tobias Lindgren wrote:
> > > Hi all,
> > >
> > > I've been trying to find this information but I cannot find any exact
> > > specifications on how it really works.
> > >
> > >  >From what I know using NAPTR/SRV records with OpenSER will allow
> > it to
> > > find and use servers behind those DNS-records. This works just fine.
> > >
> > > However, what I'm not sure about is what actually will happen in
> > OpenSER
> > > when one of two servers in this scenario would fail.
> > >
> > > For example, I have two servers as SRV where one is primary and one is
> > > secondary for SIP/UDP. What will happend in OpenSER when the primary
> > > server is down? Will OpenSER continue to send all request first 
> towards
> > > that server or will it learn that one server is down and always send
> > > requests to the second server for a period of time and try the primary
> > > one just occassionally?
> > >
> > > Please direct me to any page where this is explained in detail, if 
> such
> > > page exists.
> > >
> > > Br,
> > > /Tobias
> > >
> > > _______________________________________________
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> > >
> > >
> >
> >
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