Re: [SWMP] My understanding so far

Roland Weber <ossfwot@dubioso.net> Fri, 31 August 2007 20:55 UTC

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Date: Fri, 31 Aug 2007 22:55:52 +0200
From: Roland Weber <ossfwot@dubioso.net>
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To: john_patterson@us.ibm.com
Subject: Re: [SWMP] My understanding so far
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Hi John,

> I did not understand that about tickets.

Tickets are used similar to session cookies. When a network
element X opens the initial channel to Y, it sends a message
"HELLO, I am X and here is your ticket YtoX for contacting me".
>From then on, Y is expected to use the ticket YtoX whenever it
sends a packet to X, on any UDP (side) channel. Likewise, X
gets a ticket XtoY in the HELLO message from Y.
There must be some mechanism to ensure that HELLO messages
exchanged on side channels use the same tickets as on the
main channel. Or else different HELLO messages could be used
for side channels, without tickets.

> As I have mentioned 
> elsewhere, I no longer believe that message IDs are a good idea for 
> subscriptions.

That was in a mail you didn't copy to the list, that's
why I came back on this topic.

> I still think that failure notifications and queries will 
> be needed.

They make a lot of sense to me.


> I agree with your point about using message IDs on subscriptions.  We 
> could just say that all subscriptions are followed by a full accounting of 
> the state.

Good point. Not the first time that I am overlooking the
most simple solution to a problem :-)

> Or, if we want to manage the traffic better, we will need some 
> notion of time to account for how far back the subscriber's state is 
> valid.  If we can figure out how to use time in this fashion, it might 
> decrease the traffic a lot.

Yes. It pulls in a lot of complexity though.

cheers,
  Roland



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