Subject: [NSIS] Interim meeting notes from IETF 56

From: [email-masked]
Date: Tue, 1 Apr 2003 16:07:06 +0300

Hi all,

At IETF 56, I presented a short summary of the interim meeting - what I thought
were some important points.  If I have left anything out or misconstrued things,
please speak up.

	- Seperate transport layer protocol state from NTLP state 
	- Soft-state refresh supported independent of transport protocol state.
	- Extensibility should be provided (see something which a node does 
	  not understand, session should not fail)
	- Seperate flow identifier and session identifier.
	- Session identifier should be unique.
	- Don't overload ids
	- Link-based congestion control is not a good thing.
	- Scoping of requests should be avoided (see IPv6 mailing list)

Thanks,
John
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From: "Hancock, Robert" <[email-masked]>
Date: Tue, 1 Apr 2003 14:49:11 +0100

john,

> 	- Seperate transport layer protocol state from NTLP state 

IIRC what was discussed was separating signalling application state
from NTLP state; for example, even if the NTLP uses a 'connection'
concept, the signalling application state doesn't fate-share with it.

Maybe a better phrasing would be 'any internal state used by the NTLP
is not visible outside the NTLP'. 

[I think we're in agreement on this, it's just a question of
how to say it.] 

(The distinction between 'transport layer protocol state' and 'NTLP state'
is somewhat awkward since 'TLP' stands for 'transport layer protocol' as well.
Personally, I would rather call the NTLP something else. What we are
sometimes trying to do is discuss how NSIS-specific functions 
interact with general transport-related functions, but that's hard to do
in protocol terminology without making provocative assumptions about the 
design of what goes below the signalling applications.)

> 	- Link-based congestion control is not a good thing.

The minutes and my recollection of this discussion are equally confused.
I think it was clear that relying *only* on local congestion control is 
not good enough, you need something operating above it as well. If the
claim is that local congestion control is actually *harmful*, I'd be 
interested in a pointer. In particular, I don't see how TCP experience
can be directly applied here since, as well as the flow endpoints, there are 
locations inside the network which keep state and generate messages 
autonomously.

> 	- Scoping of requests should be avoided (see IPv6 mailing list)

In retrospect, I think we didn't do justice to this question. The scoping
question that is relevant to NSIS is something like
'limiting the region in which a message can be propagated'
which a lot of people seem to like (it's just RSVP proxy operation).

The violent, interminable, mind-numbing v6 scoped address argument is I 
think about quite different things - in particular, the origin of the 
controversy is in the ability to use ambiguous identifiers, to have 
identifiers which can be locally allocated, and so on. No one is proposing
anything of the sort for NSIS [yet!!], so the v6 lesson doesn't apply.

(Which layer - NTLP/NSLP - should play a part in such scoping is of course
still very open.)

> John

a pleasure,
robert h.