Subject: RE: [Ietf-behave] Two suggestions for BEHAVE document

From: "Francois Audet" <[email-masked]>
Date: Thu, 2 Sep 2004 10:11:27 -0700 (PDT)

Sounds reasonable. Do you think we should define the failure mode?
(I personally think we should, so that our document is deterministic).
Or do you think we should just do a RECOMMEND?

What is your preference: "deterministic" or "conservative"?

PS: This document applies to UDP only, not TCP where these rules wouldn't
make sense. So the examples you have HTTP/SMTP/POP wouldn't apply, right?
Personnally I would imagine that the majority of UDP traffic is 
RTP/RTCP. Am I mistaking?

I'm OK on either although I prefer the "deterministic" approach.

Other opinions?

> -----Original Message-----
> From: Melinda Shore [mailto:mshore@xxxxxxxxx] 
> Sent: Thursday, September 02, 2004 09:53
> To: Audet, Francois [SC100:9T51:EXCH]
> Cc: 'Behave'
> Subject: Re: [Ietf-behave] Two suggestions for BEHAVE document
> 
> 
> Both sound good with the caveat that there may be situations 
> in which the NAT runs out of resources (either addresses or 
> ports). In those cases the NAT has several options, including 
> failing to create a mapping or creating a mapping that 
> doesn't satisfy the requirements.  Which way it needs to go 
> depends on whether you prefer that the NAT's behavior be as 
> deterministic as possible or that the NAT be as unobtrusive 
> as possible (it's reasonable to think that most of the 
> traffic traversing a NAT will not be broken by the NAT in the 
> first place - HTTP, SMTP, POP, etc.).  At any rate, I think 
> that those two requirements are reasonable as long as there's 
> some discussion of failure modes.
> 
> Melinda
> 
>

---

From: Melinda Shore <[email-masked]>
Date: Thu, 2 Sep 2004 10:23:22 -0700 (PDT)

On Thursday, September 2, 2004, at 01:08 PM, Francois Audet wrote:
What is your preference: "deterministic" or "conservative"?
I think the answer to that depends on what kind of model you're
working from.  If you've got a best-effort view of the world, it's
probably best to go with conservative.  If you've got a reliable
delivery view of the world, it probably best to go with deterministic.
My own feeling is that it's probably a mistake to allow UDP-
encapsulated IPSec to fail even though you've got resources available 
when
those available resources don't conform to what you'd need for
voice.

Melinda

---

From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 8 Sep 2004 11:09:42 -0700 (PDT)

Francois Audet wrote:

Sounds reasonable. Do you think we should define the failure mode?
(I personally think we should, so that our document is deterministic).
Or do you think we should just do a RECOMMEND?
I think you want to define it. If you define it as "fall back to 
providing a port on the other address", then a client would know that it 
should probably implement RFC 3605 (the RTCP address/port attribute in 
SDP) anyway, allowing it to still get RTCP to work in the event that the 
peer supports RFC 3605.

-Jonathan R.

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