Subject: Re: [SUA issue 17] IPSP cases.

From: "Brian F. G. Bidulock" <[email-masked]>
Date: Thu, 30 Aug 2001 05:23:01 -0500

Gery,

Verwimp Gery wrote:                                (Thu, 30 Aug 2001 11:40:54)
>
> Brian,
> 
> Just as SCCP extends the routing facilities of MTP by the ability to route
> on GT, SUA could just as easily extend the IP routing capabilities by using
> GTs, hostnames, etc. I'd make no statements about it's necessity if I were
> you.

IP already has the ability to route on hostnames and IP addresses.  IP has
already been extended to use GTTs (ENUM and others).  IP does not need
either SCCP or SUA to extend it.

> And please don't assume that there will be SCTP associations between every
> pair of conceivable communication partners.

The nice thing about SCTP connections is that you can form them when you need
them and drop them when you don't.  The same is not true for SS7 links.

> As to the COERR : is there any value in doing a (modelling) split like this
> ? As if only the SG "contains" the SUA state machines and the ASP just
> "contains" the user's state machines, leaving an "empty" SUA-shell on the
> ASP ? That's just asking for a lot of interoperability problems.

Not saying what state machine behavior one IPSP can expect of another is
the best way of inviting interoperability problems.  What state machine
behavior can my IPSP expect of yours?  Can my IPSP only expect yours to
be "impelemtnation dependent"?  We will have a hard timer interoperating...

> No, a bunch of functionality (multiple SG's, RK/RC's, connections,
> segmenting of CLDTs, ...) requires state machines. So send the COERR if the
> DLR is no recognized, and handle it on reception. How would the SG know it
> received a message for a non-existent connection in case of decoupling
> anyway ?

One answer is the proposed REG REQ procedure. Look at it.

> Please let's not have an assymetrical SUA model in order to save (?) some
> lines of code on some platform.

Gery, I am not advocating an asymetrical model.  All I'm saying is that
there is a lot missing in the draft for a symetrical one.  If you want
a symmetrical model, let's go about specifying the stuff that needs to
be in the draft to support a separate IPSP mode (as distinct from the
asymmetrical backhaul model which currently exists whether you or I like
it or not).  If you want an asymmetrical IPSP model just as the backhaul
case, please, tell me how it is supposed to work.

It is only becoming more and more obvious that the draft is lacking in
specifying IPSP behvaior.

What do you propose to resolve this issue?

(Other than me taking a long walk of a short pier...)

--brian

-- 
Brian F. G. Bidulock
[email-masked]
http://www.openss7.org/

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