Subject: MPLS Diffserv Extensions related questions/comments

From: Bora Akyol <[email-masked]>
Date: Wed, 31 May 2000 21:28:06 -0700

I have a few questions on the 4th revision of this draft. (Possibly with
more to follow)

1. Does this draft assume that an E-LSP is associated with only one prefix?
At least in our implementation, we can direct more than one prefix into a
single LSP.

2. What happens when penultimate hop popping is used for an E-LSP? The
penultimate hop really does not have knowledge about the EXP mappings in the
ultimate hop?

3. How does one tie the output of the policing element in the model to the
EXP bits on the output direction of the label. Even though the picture in
the draft shows this connection, the text does not cover this.

4. Why does the draft have so many forward references especially in Chapter
2. It would have been much better to first complete the discussion on E-LSPs
fully, then focus on L-LSPs. This makes the text difficult to follow.

5. The draft is vague on the following cases:
	a) IP to MPLS label push
	b) MPLS to IP label pop and route
	c) MPLS to IP pop, then IP to MPLS push.

6. For the people that are actually using MPLS with Diffserv rather than
just the CoS bits, how are you using it?

7. Is the terminology in the draft going to get updated to sync up with the
latest and greatest diffserv terminology ( I have to admit that I tuned out
that discussion about 3 weeks ago).

8. THIS IS A GRIPE. Did anyone consider hardware pipelining, etc while this
spec was being written? This actually is one of my biggest gripes about
Diffserv. It is so damn flexible which makes almost any HW implementation
leave out features, maybe we should have started something that was concrete
and implementable.

One suggestion, it may not be a bad idea at all to move at least one of the
examples to the front of the text to set some context.

Thanks

Bora Akyol

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From: "tom worster" <[email-masked]>
Date: Fri, 2 Jun 2000 11:20:04 -0400

From: [email-masked] [mailto:[email-masked]]On Behalf Of Bora Akyol
> leave out features, maybe we should have started something 

speaking of hardware... the requirement in diff-ext-04 for 
support of exp->phb mappings on a per lsp basis set by 
signalling does not really seem to be "hardware cost
friendly," so to speak. does anyone really need an arbitrary
mapping for each lsp?

c u
tom

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From: Curtis Villamizar <[email-masked]>
Date: Mon, 05 Jun 2000 18:19:37 -0400

In message <[email-masked]>, "tom worster"
> friendly," so to speak. does anyone really need an arbitrary

IMHO this will be useful.

It isn't really that hard.  Implementations exist.  (At least one that
I know of).

Curtis