Subject: RE: [Sigtran] M2PA list of comments on draft version 5

From: [email-masked]
Date: Mon, 22 Jul 2002 16:31:58 +0100

Hi Tom,

In relation to my comment (no. 13 below), I feel you also need to add that
'buffer flush' should take place when processor outage ceases (i.e. to the
last paragraph of 4.1.4). 
At the moment, this isn't clear in the text.

I reproduce my related comment on the use of processor outage,

'I don't believe that processor outage should be used to cover the situation
where the MTP3 or User Parts are encountering congestion, or where the User
part is unavailable. In these cases the SS7 flow control and User part
unavailability control respectively should be used. This means that local
processor outage should be only used when the M2PA at the SG detects that
the AS is down. If M2PA detects that the AS is active again, and ready to
process signalling messages, the MTP2 at the SG should stop sending link
status signalling units indicating processor outage to the remote SS7 node.
This isn't clear in the current text.'

Please can a clarification be added to the text to cover this.

Regards,

Karen

-----Original Message-----
From: Tom George [mailto:[email-masked]]
Sent: 14 July 2002 04:25
To: SIGTRAN e-mail list
Cc: Brian Tatum; Vincent MAY
Subject: [Sigtran] M2PA list of comments on draft version 5

Here is my list of comments. For the most part, they are arranged by
the thread from the SIGTRAN list.

Everyone please make comments. I think the discussion would go more
smoothly if you only talked about one item per e-mail.

1. Section 2.2. FSN/BSN should be 24 bits, not 23.

A: This was a typo. It will be 24 in M2PAv6.

2. 05/06/02 Jeff Craig "[Sigtran] (M2PA) What actions should be taken
   if LSA or User Data Received in PROVING?" There is no guidance
   about anomalous events during alignment/proving.

A: I agree that some text should be added. I have not worked out the
details and would welcome suggestions.

3. 05/10/02 Jeff Craig, "[Sigtran] (M2PA) Please standardize M2PA
   protocol timer identifiers" and Jeff Craig 06/21/02 "m2pa comment:
   timers". Line up timer names in Q.703 and M2PA. Add the T7 timer.

A: This is what I got out of the discussion:

   Keep same names for T1, T3, T4, T6.

   Rename M2PA T2 to T4.

   Don't use "timer" names for the rate parameters.

4. 05/17/02 Jeff Craig, "[Sigtran] (M2PA) Please add a Network
   Appearance parameter to the M2PA protocol". A suggestion that a NA
   parameter be added to M2PA.

A: I prefer not to add this. 

5. 05/22/02 anssharma, "[Sigtran] M2PA Clarification". In level 2 flow
   control, M2PA stops transmitting. What does it do with the
   messages?

A: I think is an implementation matter. 

6. 05/24/02 Lisa Gorgone, "[Sigtran] M2PA:Questions on sequence
   number". Some questions about bad values of FSNR and BSNR.

A: M2PAv5 (4.2.1) says to fail the link if one FSNR is out of order. I
think that is OK. There is nothing about bad BSNR values. I would be
inclined to fail the link in this case as well, since one end is
acking messages that the other does not have in its (re)transmit
buffer.

7. 05/24/02 Brian Bidulock "[Sigtran] Re: M2PA Clarification". Does
   M2PA need to withhold messages from SCTP during busy?

A: If this is how Q.703 works, we should copy it. I just sent a
question to the list about the Q.703 procedure.

8. 06/18/02 amish.chana "[Sigtran] M2PA Comment: Multi-homing". Should
   M2PA support multi-homing?

A: It is allowed. The only change needed is in 4.1.2 so that it says
"the IP address (or IP addresses if multi-homing is used)".

9. 06/19/02 Lisa Gorgone "Re: [Sigtran] M2PA Comment:Retrieval
   State". Does M2PA need a RETRIEVAL state? Does RETRIEVAL state
   cause harm?

A: I would like to have more discussion about this. 

10. 06/21/02 Javier Pastor-Balbas "[Sigtran] M2PA Comment:
    Multi-homing". Also 06/21/02 "[Sigtran] Multiplexed M2PA links on
    an association".  Should M2PA allow multiple links per
    association?

A: The disadvantage of this is that if the association dies, you lose
all the links on the association. (According to the SCTP authors, it
is intended that all the streams in an association follow the same
physical path.) This is one of the main reasons I did allow for
multiple links in an association.

11. 06/21/02 Andrew Booth "[Sigtran] M2PA Comment: T7 Timer" and
    several of the earlier threads. Should there be an equivalent of
    MTP2 T7?

A: OK, you finally convinced me. 8-)

12. 06/25/02 Lyndon Ong "RE: [Sigtran] M2PA Queries - summary". Just a
    summary of the discussion.

A: No answer needed.

13. 06/26/02 Karen King "[Sigtran] A couple of comments on M2PA
    processor outage". Recommend adding text to 4.1.4 Processor Outage
    about flushing buffers as in Q.703.

A: Even though this is in Q.703, the action is taken by MTP3. Section
4.1.4 (next to last paragraph) does allow for the flush. Flush is
described in 4.2.4. So I think this is taken care of (although there
may be problems in 4.2.4 - that's another thread).

14. 06/28/02 Ray Singh "[Sigtran] Comment on M2PA - Performance
    Monitoring". Add back the monitoring of SCTP association that was
    in draft version 3.

A: The reason I took this out is that I never had any solid ideas
about what SCTP parameters should be monitored and what the acceptable
values would be. If we could come up with something helpful, I am not
opposed to adding the monitoring back in. But I don't see the point of
adding it if the criteria will be some implementation-dependent
parameters having implementation-dependent values. 8-(

15. 07/12/02 anssharma "[Sigtran] M2PA - Flush Buffers". Questions
    about Flush.

A: These are good questions but I have not had time to think about
them.

-- 
* Tom George          972-519-3168           [email-masked]   *
* PB2-1323       Intranet:  http://www.ssd.usa.alcatel.com/~tgeorge/  *
* Alcatel USA, Inc.; 1000 Coit Rd, MS PB2-STPA; Plano TX 75075-5813   *
* I actively disclaim speaking for Alcatel USA, Inc. I do not purport *
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---

From: "Tolga Asveren" <[email-masked]>
Date: Mon, 22 Jul 2002 12:05:19 -0400

Karen,

> From: [email-masked] [mailto:[email-masked]]On Behalf Of
> [email-masked]
> Sent: Monday, July 22, 2002 11:32 AM
> To: [email-masked]; [email-masked]
> Subject: RE: [Sigtran] M2PA list of comments on draft version 5
>
>
> Hi Tom,
>
[TOLGA] What do you refer to exactly when you say AS? The users of M2PA or
another M2PA peer?