[Sip] Re: WGLC comments on sip-outbound-10

[Rohan Mahy <[e-mail]>]

Hi,

My comments and a question or two inline.
thanks,
-rohan

On Aug 3, 2007, at 4:20 PM, Francois Audet wrote:
> Some more WGLC on sip-outbound-10
> ---------------------------------
>
> Section 4.4: change "timed-keepalives" to "time-keepalive" (there  
> are at
> least 2 instances of
> this mistake).

fixed in -11

> -------
>
> The example in section 9 should use TCP instead of of UDP, since  
> TCP is
> preferred (as
> discussed in section 14). Furthermore, if the UDP example is used, it
> should show
> the rport parameter in the Via header.

I plan to completely revamp the example and will incorporate these  
comments.

> It should be clarified that the last paragraph of 4.3 only applies to
> UDP.

ok, I added, then accidentally deleted this in -11.  This is now  
fixed in my local copy.

> ------
>
> I would like to see more details in section 9 about how the "ob",
> "rport" and Route and
> Record-Route headers (i.e., including the keep-XXX parameter) are used
> by a UA that
> supports outbound procedures, when sending requests using Outbound  
> (like
> INVITE for example).
>
> Also, it would be helpful to see an example where the outbound  
> proxy is
> not co-located with the Registrar, so we could see how the Path header
> is used,
> including the "ob" parameter (as per the procedures of 5.1). This  
> stuff
> is non-trivial
> and would benefit greatly from an example flow (with the messages
> content).
> Distinguishing between 'ob' in Contact and in Path/Route seems
> important.
>
> In other words, a flow (with messages) illustrating what an edge proxy
> does for both
> registration and for further requests such as INVITE

I am going to completely rewrite the example based on your advice here.

> ------
>
> Finally, the procedures in 5.3 on "incoming" requests is not that  
> clear
> on what it actually
> mean "on the wire". It says the following:
>
>    For an incoming request, the proxy removes
>    the Route header field value and forwards the request over the
>    'logical flow' identified by the flow token, that is known to  
> deliver
>    data to the specific target UA instance.
>
> Does it just mean that the request will be forward on the same TCP or
> UDP flow, and
> that there is no additional requirements?

correct

> Nothing on the wire that will
> show that outbound
> is being used (Is the flow token supposed to be inserted by the  
> Proxy)?

nothing on the wire

> On that front,
> message 8 in the example of section 9 has a flow token, where does it
> come from?
> This is very confusing since the Caller might not use Outbound, so  
> where
> does this
> token come from, and what it is used for in this example? How is the
> token of the
> Callee given to the Caller???

The existing example is wrong in many ways and will be completely  
replaced.

> It is also no clear from the
> example how the Caller knows to reattempt the INVITE to the secondary
> proxy (wouldn't
> this be handled in the terminating side's domain?).
>
> There is no description of UAS requirements in the draft. Does it mean
> that there are none
> whatsoever? (I'm talking about a UAS that is using outbound receiving
> incoming requests). If
> so, there should be a UAS section stating so.

do you think Section 4 should have a separate subsection?  All you  
need to do is leave your flow open and be prepared to receive  
messages over it.

> Is it possible for example that incoming requests might be received by
> the UAS on different
> flows (because of reboot for example)? In the same session??

Yes.

thanks,
-rohan


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