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Re: [SCTP-Discussion] Notify Message Treatment


Chronological Thread 
  • From: "Brian F. G. Bidulock" <bidulock AT openss7.org>
  • To: Sundaresan M <sundarem AT future.futsoft.com>
  • Cc: discussion AT sctp.de
  • Subject: Re: [SCTP-Discussion] Notify Message Treatment
  • Date: Sun Dec 30 14:12:01 2001
  • Dsn-notification-to: <bidulock AT openss7.org>
  • List-id: SCTP Discussions <discussion.sctp.de>
  • Organization: http://www.openss7.org/

Sundaresan,

On Sat, 29 Dec 2001, Sundaresan M wrote:

> Hi,
>
> I would like to know how the Motify messages are treated in the Adaptation
> layers like IUA, M3UA etc.
>
> QUESTION 1
> **********
> Configuration 1: One ASP and One SG
> -------------------------------------
> ASP is moving from Inactive state to Active state. Now the AS state changes
> from AS_INACTIVE to AS_ACTIVE. Will a Notify message be sent by the SG to
> this one and only ASP in the Configuration. Will this treatment change
> depending on the AS_STATE change also. What I mean is, if the state changes
> from Active to Inactive will this ASP(being the last one in the AS) receive
> a Notify(AS_PENDING)!!

"A Notify message reflecting a change in the AS state MUST be sent
to all ASPs in the AS, except those in the ASP-DOWN state, with
appopriate Status Information and any ASP Identifier of the failed
ASP." - M3UA-10

A Notify("AS-Pending") "MUST" be sent to the ASP.

>
> QUESTION 2
> ***********
> Configuration 2: Two ASP's (ASP1 and ASP2) with One SG:
> ------------------------------------------------------
> ASP 1 : Active
> ASP 2 : Inactive
>
> Now ASP1 moves from Active to Inactive due to LM primitives. Will the
> Notify(AS_PENDING) message be sent to Both ASP1 and ASP2 serving the SG? or
> will it be sent only to ASP2.

"If no other ASPs in the Application Server are in the state
ASP-ACTIVE, the SGP MUST send a Notify message ("AS-Pending") to
all of the ASPs in the AS which are in the state AS-INACTIVE."
- M3UA-10

The message "MUST" be sent to both ASP1 and ASP2.

>
> QUESTION 3
> **********
> Will the AS_STATE be maintained in the database by the individual ASP's.

The ASP will need to know what state it is in for each AS that it serves.

>
> QUESTION 4
> **********
> Some Stack implementors say that NOTIFY message treatment is optional. Does
> this mean that the usage of the Notify itself is optional. If it is so then
> how will the ASP's know the AS_state and will act on AS_State changes?

Sending of the Notify message is not optional. The response of the ASP to the
Notify message is not proscribed. There is a difference. Notify messages
are considered advisory in that it is up to the ASP to consider the
information in the Notify message and other information that it has at its
disposal (such as a knowledge of the state of other ASPs) before deciding what
action to take.

Hope that helps.

--brian

--
Brian F. G. Bidulock ¦ The reasonable man adapts himself to the ¦
bidulock AT openss7.org
¦ world; the unreasonable one persists in ¦
http://www.openss7.org/ ¦ trying to adapt the world to himself. ¦
¦ Therefore all progress depends on the ¦
¦ unreasonable man. -- George Bernard Shaw ¦




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