> > What I mean is that the error response may not be delivered 
> to the UAC 
> > because a forking proxy will only deliver one final 
> response. If there 
> > are multiple error responses on the individual forks, one being the 
> > one with the RPH, and the other being some other response, 
> it is up to 
> > the proxy to decide which one to forward back.
> > 
> > So the UAC can not rely on receiving the RPH to "re-intiate" the 
> > session or provide some alternative treatment. This may or 
> may not be 
> > a problem depending on the application (that's why I said "if it 
> > absolutely has").
> > 
> 
> I don't think that will be a problem. 
> 
> For one thing (for the namespaces I am working with) the 
> expectation would be that ALL the responses (except 100 and 
> 403) would have the RPH on the response, so it wouldn't 
> matter which one made it back to the UAC. 

I am not talking about multiple provisional responses from the same
endpoint.

I am talking about multiple responses (provisional and final) from 
multiple forks. For example, multiple 4XX responses.

While it is possible that a single forking proxy may decide to 
include the RPH in all responses, that proxy has absolutely no 
control over downstream and upstream proxies who may not include it
(they may be proxies in different domains).

That's the point I'm trying to make. You can not enforce the 
presence RPH in responses in a global system.

> Secondly, the expectation is that the devices responsible for 
> "re-initiating" WOULD be stateful, and not dependant on the 
> information in the RPH in the response.  It is the 
> intervening devices that might not be stateful, and would 
> take advantage of the RPH information in the responses. 

That is precisely the type of clarfication that needs to be included
in the draft. It points out the constrainsts of the mechanism so 
implementors use the feature properly.

Some text explaining that the UAC needs to be able to deal with the RPH
not being present in responses gracefully (and why) is needed.

Similar text for proxies also need to be there. What if a proxy 
forwards a request with RPH and it receives nultiple responses from
the downstream proxies, with some including the RPH and others not
including it? Does this need to be standardized?


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