Subject: [Sigtran] ASP load sharing..

From: "Mohan Parthasarathy" <[email-masked]>
Date: Wed, 11 Dec 2002 12:49:09 -0800

Hello,

In draft-ietf-sigtran-sua-14.txt, section 4.3.4.3 ASP active procedures,
I can see the following text :

	All ASPs within a loadsharing mode AS must be able to process
any
      Data message received for the AS to accommodate any potential 
	failover or reblancing of the offered load.

I have a couple of questions regarding load sharing and questions
specific
to the above text:

1) There is no mention about what can be load-shared across different
ASPs ?
   May be it is obvious or I missed some section of the draft. Could
someone
   point me to the right text ?

2) Does the "Data message" in the above text mean the connectionless and
   connection-oriented messages (Message class 7 and Message 8) ?

3) If an ASP fails where an ASP itself could not indicate to the SG but
    e.g. SCTP heartbeat indicates that an ASP failed, will the messages
be
    sent to the other ASPs because there was no ACK for the messages ?

4) When an ASP fails, most likely it will not be able to indicate to the
   SG that it failed. SCTP heartbeat may be slow to discover that ASP
failed.
   Is there a mechanism that can be used to indicate to the SG that an
ASP
   failed ?

I am new to this group. So, bear with my dumb questions.

thanks
mohan

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---

From: "Brian F. G. Bidulock" <[email-masked]>
Date: Wed, 11 Dec 2002 18:00:47 -0700

Mohan,

Mohan Parthasarathy wrote:                           (Wed, 11 Dec 2002 12:49:09)
> 	All ASPs within a loadsharing mode AS must be able to process any

The text is borrowed from M3UA (RFC 3332) so it might not be as obvious
for SUA.

> 
> I have a couple of questions regarding load sharing and questions specific
> to the above text:
> 
> 1) There is no mention about what can be load-shared across different ASPs ?
>    May be it is obvious or I missed some section of the draft. Could someone

SCCP User traffic.

>    connection-oriented messages (Message class 7 and Message 8) ?

Yes.  But is also has to address SSNM.

>     e.g. SCTP heartbeat indicates that an ASP failed, will the messages be

Sending unacknowledged messages can lead to duplication.  See
draft-bidulock-sigtran-corid-00.txt for an analysis of the situation an
a method using the Correlation Id parameter which can avoid both duplication
and message loss in this scenario.

>    SG that it failed. SCTP heartbeat may be slow to discover that ASP failed.
>    Is there a mechanism that can be used to indicate to the SG that an ASP
>    failed ?

No.

--brian

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

---

From: Tolga Asveren <[email-masked]>
Date: Wed, 11 Dec 2002 20:19:08 -0800 (PST)

Mohan,

Another thing is, to detect SCTP association failures,
one will rely on number of retransmits. For most of
the cases, I wouldn't expect that a heartbeat with
long periods will have a big impact.

    Tolga
--- "Brian F. G. Bidulock" <[email-masked]>
> indicate to the SG that an ASP

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