Re: Comments on draft-li-ccamp-multinodes-gr-proc-00.txt,

[Dan Li <danli@huawei.com>]

Hi Femi,

Thanks for your valuable suggestion! 

The intention for this draft is clarify the procedures for multi-nodes restart, so five typical scenarios have been listed in the draft, I think most of the failed cases are covered by these five scenarios. As you have pointed out, these scenarios may be raised due to multiple nodes fail, or a subsequent control channel failure. Yes, you're right! It may be more generic to classify these scenarios, such as: "What should happen if a restarting node fails to get a RecoveryPath/Path message from its downstream/upstream neighbor?", but I think it may be more clear to address the specific cases in the draft at least during the initial stage.

Any comments are very welcome!

Best regards,

Dan



 
----- Original Message ----- 
From: Olufemi Komolafe 
To: danli@huawei.com ; gjhhit@huawei.com 
Cc: ccamp 
Sent: Tuesday, September 19, 2006 8:45 PM
Subject: RE: Comments on draft-li-ccamp-multinodes-gr-proc-00.txt,


Hi,
 
While reading this draft it occurred to me that perhaps it might be more useful to approach this topic from the perspective of "What can go wrong during graceful restart, what are the consequences and how can it be fixed?" rather than focusing on the narrower topic of multiple simultaneous nodal faults.
 
For example, Scenario 1 in the draft may be interpreted as "What should happen if a (non-ingress) restarting node fails to get a RecoveryPath message from its downstream neighbour?", Scenario 2 is "What should happen if a (non-ingress) restarting node fails to get a Path message from its upstream neighbour?" and so on.  Whether each of these scenarios arises due to multiple simultaneous nodal faults (as in the draft) or any other reason (e.g. a subsequent control channel failure, restarting node being inundated with messages etc.) is, in my opinion, secondary.  I think the key thing is to identify the potential problems and suggest appropriate remedial actions, where the authors think existing documentation is insufficient, rather than focusing on 5 different permutations of multiple node graceful restart.   
 
Regards,
Femi
 
 



From: owner-ccamp@ops.ietf.org [mailto:owner-ccamp@ops.ietf.org] On Behalf Of Zafar Ali (zali)
Sent: 10 July 2006 04:04
To: danli@huawei.com; gjhhit@huawei.com
Cc: ccamp
Subject: Comments on draft-li-ccamp-multinodes-gr-proc-00.txt, 
 
Dear Authors, 
 
This is Deja-vu to me.... 
 
Draft draft-ietf-ccamp-rsvp-restart-ext-05.txt actually had a section on multiple node restart case and was rejected by the WG as addressing multiple node restart case is NOT a goal (suffers from the law of diminishing return). In other words the following statement in the ID- 
 
   "[GR-EXT] also extends the Hello message to exchange information about 
   the ability to support the RecoveryPath message. 
   The examples and procedures in [GR-EXT] focus on the description of a 
   single node restart when adjacent network nodes are operative. 
   Although the procedures are equally applicable to multi-node restarts, 
   no detailed explanation is provided." 
 
is not accurate. Please see section 4 on the earlier version of the [GR-EXT], http://www.faqs.org/ftp/pub/internet-drafts/draft-rahman-ccamp-rsvp-restart-extensions-00.txt. 
 
Thanks
 
Regards... Zafar