Subject: RE: [Sigtran] Recommendation for SUA modifications

From: "Haresign Lincoln" <[email-masked]>
Date: Fri, 14 Oct 2005 11:36:11 -0400

Brian,

1) if multiple ASPs or AS can use the same association, this is a
scenario where you wouldn't want to use SCTP flow control.

2) SCTP flow control would reduce or eliminate ALL traffic going to an
ASP.  It may be that you want to see management messages, but not data
messages.

3) Peer-to-peer flow control allows an SG to implement features such as
reducing traffic to a lower threshold.  Much of this might be
implementation dependent.  A congestion level of 1 would reduce traffic
by 25%, 2 - 50%, etc...  Or a congestion level of 1 would only let
through certain application contexts, or only new dialogs.  In any case,
all of this is really implementation dependent, but allows switch
vendors to implement unique/configurable features in their products that
will still interop with all other switches.

Regards,
Lincoln 

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Brian F. G. Bidulock
Sent: Friday, October 14, 2005 10:46 AM
To: Tolga Asveren
Cc: [email-masked]; [email-masked]; [email-masked]
Subject: Re: [Sigtran] Recommendation for SUA modifications

Tolga,

What were the scenarios where SCTP flow control (arwnd) do not work?

Could you detail them?

I would like to capture them in my congestion draft.

--brian

Tolga Asveren wrote:                            (Fri, 14 Oct 2005
09:34:42)
> Brian,
> 
> On the big picture I agree with you that SSNM is meant to be used for 
> SS7 network management, hence SCON is supposed to be used for SS7 
> congestion procedures. OTOH, there is a need to notify congestion 
> status of ASPs to SG and right now it seems like we don't have a 
> solution -actually till now the supposed solution was relying on SCTP 
> congestion but there are scenarios where this is not enough/does not 
> work well-. I believe something needs to be done to address that
issue.
> a)Either a new ASPTM
> b) or overloading SCON
>     Thanks,
>     Tolga

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

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---

From: "Brian F. G. Bidulock" <[email-masked]>
Date: Fri, 14 Oct 2005 10:03:09 -0600

Licoln,

Haresign Lincoln wrote:                                                            (Fri, 14 Oct 2005 11:36:11)
> scenario where you wouldn't want to use SCTP flow control.

Your right again!  The SUA specification is deeply flawed.  It currently
only allows 1 ASP per association.  It needs to be enhanced to allow multiple
ASPs per association.  That should be possible with an I-G entry.  We could
just add the ASP Id parameter to all the messages so that the SGP can distinguish
between all the ASPs on the association.  Hey!  Why not multiple SGPs per
association too!  We could use the ASP Id in all the messages in the other
direction.

> ASP.  It may be that you want to see management messages, but not data

Yes, MTP doesn't do this well.  It only has one buffer per links so it
splits it up into multiple onset and abatement threadsholds and prioritizes
management messages.  It create that horrible overhead of assigining two bits
of message priority to each message.  That would never do for SCTP.

> will still interop with all other switches.

Yes, SCCP does that using a dual timer method, but we don't want to rely
on that for SUA.  We need a completely different, much better mechanism.

Do you think you could provide some text describing this better mechanism for
the ASP Congestion draft?

--brian

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

---

From: "Tolga Asveren" <[email-masked]>
Date: Fri, 14 Oct 2005 12:51:56 -0400

> From: Brian F. G. Bidulock [mailto:[email-masked]]
> Sent: Friday, October 14, 2005 12:03 PM
> To: Haresign Lincoln
> Cc: Tolga Asveren; [email-masked]; [email-masked];
> [email-masked]
[TOLGA]I think to use more than one association for multiple ASPs deserves
some discussion. As a first question, why do we need multiple ASPs traffic
on a single association? I know the "P" in ASP stands for "process" but OTOH
practically it maps to a host -at least as far as I can see-. My opinion
about that one is to be more cautious and if possible move forward with 1:1
relationship between M3UA peer:SCTP association in the context of ASP
congestion draft.

---

From: "Tolga Asveren" <[email-masked]>
Date: Fri, 14 Oct 2005 13:00:29 -0400

please see below for typo corrected

> From: [email-masked] [mailto:[email-masked]]On
> Behalf Of Tolga Asveren
> Sent: Friday, October 14, 2005 12:52 PM
> To: [email-masked]
> Subject: RE: [Sigtran] Recommendation for SUA modifications
>
>
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