Subject: [P2PSIP] draft-maenpaa-p2psip-self-tuning-01

From: Cullen Jennings <[email-masked]>
Date: Sun, 8 Nov 2009 09:12:10 +0900

I like this draft and would love to seem some experimental data from  
operational networks playing with it.

I'm not sure what anyone else things, but I think it would be worth  
considering moving just one small part of to the base draft - namely  
Section 5.6.1.

On the Pro side for doing this:  It's really easy to implement and it  
would provide some interesting options for future things such as this  
self tuning draft.

On the Con side for doing this: in many DHT, a large percentage of  
nodes leave without sending nay signaling that they are going to Leave  
so specifying what goes in a Leave message might be a little optimistic

Cullen <in my individual contributor role>

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From: Jouni Mäenpää <[email-masked]>
Date: Sun, 08 Nov 2009 10:12:13 +0900

Hi Cullen,

Thanks for your comments. See inline for my answers.

Regards,
Jouni

> considering moving just one small part of to the base draft - namely

I see no problem with doing that.

> would provide some interesting options for future things such as this

The nice thing about self-tuning is that it automatically determines
appropriate values for the DHT parameters that are otherwise very
difficult to configure manually. An example is the stabilization rate.

> On the Con side for doing this: in many DHT, a large percentage of nodes
> leave without sending nay signaling that they are going to Leave so
> specifying what goes in a Leave message might be a little optimistic

I agree that many nodes may leave without sending any Leave messages
(i.e., crash). The mechanism works even without the data included in
Leave messages; including data in them is just an optimization that
speeds up recovery from peer departures in those cases in which peers
send explicit leave signaling. Section 6.3.1 of the draft deals with
failure detection (e.g., how for instance crashed peers are detected).

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From: Enrico Marocco <[email-masked]>
Date: Mon, 9 Nov 2009 13:34:00 +0900

> so specifying what goes in a Leave message might be a little optimistic

Considering also detected failures other than bye messages seems a
pretty straightforward next step. I don't have an opinion whether this
should be in the base specs or defined as an extension, but totally
agree that a self-configuration mechanism is definitely worth having in
any real DHT deployment.

-- 
Ciao,
Enrico