Re: [sipcore] Bypassing out-of-service intermediate Proxy

Adam Roach <adam@nostrum.com> Thu, 02 September 2010 17:39 UTC

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Cc: sipcore@ietf.org
Subject: Re: [sipcore] Bypassing out-of-service intermediate Proxy
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  [as participant]

This is talking about failing over to an alternate server that serves 
the same function, not a proxy further down the path. This is a bit 
clearer if you look at section 4.3 of RFC 3263.

Trying to fail "around" the server by going to the next network element 
in the route would *not* be compliant with RFC 3261 behavior.

/a

On 9/2/10 11:56 AM, youssef.chadli@orange-ftgroup.com wrote:
>
> Hi all,
>
> I have a question regarding routeing of SIP requests and usage of ROUTE.
>
> When a proxy or UA fails to send a SIP request to the next hop 
> (because this latter is not reachable) is it allowed to bypass this 
> hop and send the request to the hop whose URI is next in ROUTE header.
>
> According to section 21.5.4 of RFC 3261, this proxy behaviour seems 
> allowed. See text in bold below:
>
> Any opinions on this?
>
> */21.5.4 503 Service Unavailable/*
>
>
> /The server is temporarily unable to process the request due to a 
> temporary overloading or maintenance of the server.  The server MAY 
> indicate when the client should retry the request in a Retry-After 
> header field.  If no Retry-After is given, the client MUST act as if 
> it had received a 500 (Server Internal Error) response./
>
> /A client (proxy or UAC) receiving a 503 (Service Unavailable)* SHOULD 
> attempt to forward the request to an alternate server.*  It SHOULD NOT 
> forward any other requests to that server for the duration specified 
> in the Retry-After header field, if present./
>
> /Servers MAY refuse the connection or drop the request instead of 
> responding with 503 (Service Unavailable)./
>
>
> Youssef CHADLI
> Orange Labs
>
>
>
>
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