Subject: [Sigtran] M3UA Loadsharing Case, Withdrawal of ASP

From: "Ambika Tripathy" <[email-masked]>
Date: Thu, 10 Jul 2008 19:36:19 +0530

Hi Folks,

I have a doubt in section 5.2.3 of rfc 4666.
*5.2.3.  n+k Sparing, Loadsharing Case, Withdrawal of ASP*

*   Following from the example in Section 5.1.4, ASP1 withdraws from
   service:*

*        SGP                 ASP1                ASP2                ASP3
          |                   |                   |                   |
          |<----ASP Inact.----|                   |                   |
          |---ASP Inact Ack-->|                   |                   |
          |                   |                   |                   |
          |--NTFY(Ins. ASPs)->|                   |                   |
          |---------------------------------------NOTIFY(Ins. ASPs)-->|
          |                   |                   |                   |
          |                   |                   |                   |
          |<----------------------------------------ASP Act (Ldshr)---|
          |------------------------------------------ASP Act (Ack)--->|
          |                   |                   |                   |
          |-NTFY(AS-ACTIVE)-->|                   |                   |
          |-------------------NOTIFY(AS-ACTIVE)-->|                   |
          |---------------------------------------NOTIFY(AS-ACTIVE)-->|
          |                   |                   |                   |
          |                   |                   |                   |*

*   For the Notify message to be sent, the SG maintains knowledge of the
   minimum ASP resources required (e.g., if the SG knows that "n+k" =
   "2+1" for a Loadshare AS and "n" currently equals "1").*

*   Note: If the SGP detects loss of the ASP1 M3UA peer (e.g., M3UA
   heartbeat loss or detection of SCTP failure), the initial ASPs
   Inactive message exchange (i.e., SGP-ASP1) would not occur.
*

Question>>
1. When ASP1 withdraw request from AS and ASP3 becomes active why SG will
notify ASP2 with AS-ACTIVE??? As per my understanding the state of ASP2 is
not changed.

-- 
Br,
Ambika Prasad Tripathy
Nethawk Networks
Cell: +91-94375 47730
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---

From: "Brian F. G. Bidulock" <[email-masked]>
Date: Thu, 10 Jul 2008 08:31:34 -0600

Ambika,

The diagram in section 5.2.3 of RFC 3332 is correct.
RFC 4666 is in error here.

--brian

Ambika Tripathy wrote:                                                                                                                                            (Thu, 10 Jul 2008 19:36:19)
>    I have a doubt in section 5.2.3 of rfc 4666.
<snip>---
> 
>    Question>>
> 
>    1. When ASP1 withdraw request from AS and ASP3 becomes active why SG
>    will notify ASP2 with AS-ACTIVE??? As per my understanding the state
>    of ASP2 is not changed.
> 
<snip>---

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

---

From: "David Laight" <[email-masked]>
Date: Thu, 10 Jul 2008 17:19:55 +0100

My interpretation is that the NTFY(AS-ACTIVE) reports the state
at the SGP, not at each ASP.
See 5.1.2 where both ASP1 and ASP2 are sent the AS_ACIVE when
ASP1 sends and activate.

In 5.2.3 the NOTIFY(AS-ACTIVE) is sent to all ASPs in order
to reverse the NOTIFY(Ins. ASPs) sent earlier.

	David

> -----Original Message-----
> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of Brian F. G. Bidulock
> Sent: 10 July 2008 15:32
> To: Ambika Tripathy
> Cc: sigtran; [email-masked]
> Subject: Re: [Sigtran] M3UA Loadsharing Case, Withdrawal of ASP
> 
> Ambika,
> 
> Ambika Tripathy wrote:                                        
>                                       (Thu, 10 Jul 2008 19:36:19)
> > 
> >    Hi Folks,
> > 

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---

From: "Brian F. G. Bidulock" <[email-masked]>
Date: Thu, 10 Jul 2008 10:23:18 -0600

David,

Hmm.  Where did you see that stated in RFC 4666?

I can't really think that AS-ACTIVE reverses Ins. ASPs as
an AS can be AS-ACTIVE and have insufficient ASPs at the
same time.

--brian

David Laight wrote:                           (Thu, 10 Jul 2008 17:19:55)