Subject: [mpls] Re: [Tsvwg] WG last call: draft-ietf-tsvwg-ecn-mpls-01

From: Magnus Westerlund <[email-masked]>
Date: Wed, 05 Sep 2007 17:46:21 +0200

Hi,

This WG has concluded without any objections. We will now request
publication of this document.

Cheers

Magnus

Magnus Westerlund skrev:
> This announces the WG last call on "Explicit Congestion Marking in MPLS"
> with the intended status of Proposed Standard. Due to vacation times the
> WG last call will run for 3 weeks. The WG last call ends the 21st of
> August.
> 
> http://www.ietf.org/internet-drafts/draft-ietf-tsvwg-ecn-mpls-01.txt
> 
> 
> Magnus Westerlund
> 
> IETF Transport Area Director & TSVWG Chair
> ----------------------------------------------------------------------
> Multimedia Technologies, Ericsson Research EAB/TVM/M
> ----------------------------------------------------------------------
> Ericsson AB                | Phone +46 8 4048287
> Torshamsgatan 23           | Fax   +46 8 7575550
> S-164 80 Stockholm, Sweden | mailto: [email-masked]
> ----------------------------------------------------------------------
> 
> 
> 

-- 

Magnus Westerlund

IETF Transport Area Director & TSVWG Chair
----------------------------------------------------------------------
Multimedia Technologies, Ericsson Research EAB/TVM/M
----------------------------------------------------------------------
Ericsson AB                | Phone +46 8 4048287
Torshamsgatan 23           | Fax   +46 8 7575550
S-164 80 Stockholm, Sweden | mailto: [email-masked]
----------------------------------------------------------------------

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---

From: Lars Eggert <[email-masked]>
Date: Tue, 11 Sep 2007 12:40:40 +0300

Hi,

I reviewed draft-ietf-tsvwg-ecn-mpls, and think it is ready to move  
to IETF last call, modulo a resolution to some small issues:

(1) Section 8.3 doesn't really discuss an "example use", which is  
what the title of Section 8 is. Suggest to cut it or move the content  
elsewhere.

(2) I'd make sense to swap Sections 8 and 9, i.e., discuss deployment  
considerations before example uses.

(3) My recollection was that there was an agreement to move the  
discussion of how one would use this to support PCN to an appendix.  
Some of this has happened, but Section 8.4 still exist in the main  
body of the document, and is longer than all the other example uses.  
I suggest to replace the content of Section 8.4 with a pointer to the  
appendix, and move the PCN details there.

(4) Can the reference to [Briscoe] be made more concrete, i.e., can  
it point at something that people can actually get at?

Lars

---

From: Bruce Davie <[email-masked]>
Date: Wed, 12 Sep 2007 10:04:25 -0400

Lars,
  Thanks for the comments. Before I respond to them, I wanted to  
mention one change that Bob and I want to make in the next revision  
in addition to the changes you request. It is just a small point of  
clarification, but we don't want to surprise anyone. The proposed new  
text, which would appear at the end of Section 6, is included below:

We note that in a network where L-LSPs are used, ECN marking SHOULD  
NOT cause packets from the same microflow but with different ECN  
markings to be sent on different LSPs. As discussed in [RFC3270],  
packets of a single microflow should always travel on the same LSP to  
avoid possible misordering. Thus, ECN marking of packets on L-LSPs  
SHOULD only affect the EXP value of the packets.

-----
Now to your comments

On Sep 11, 2007, at 5:40 AM, Lars Eggert wrote:

> what the title of Section 8 is. Suggest to cut it or move the  
> content elsewhere.

In my mind, section 8.3 is an example of how you can use ECN in MPLS  
networks. I think the problem here is that we didn't say enough to  
make that apparent. At the same time, I don't really see any harm in  
dropping the section.

>
> (2) I'd make sense to swap Sections 8 and 9, i.e., discuss  
> deployment considerations before example uses.

No problem.

> body of the document, and is longer than all the other example  
> uses. I suggest to replace the content of Section 8.4 with a  
> pointer to the appendix, and move the PCN details there.

We certainly moved all the protocol details around PCN support to an  
appendix as previously agreed. I have no problem moving most of this  
section to an appendix too.

> it point at something that people can actually get at?

Of course. The internet draft to which we were referring did not  
exist at the time of the last draft, but now it does: draft-briscoe- 
tsvwg-ecn-tunnel-00.txt will be the new reference. However, RFC  
editor style is to remove the filename of the draft from the  
references again, so I think this will look pretty much the same upon  
publication.

Bruce

---

From: "James M. Polk" <[email-masked]>
Date: Wed, 12 Sep 2007 13:05:45 -0500

I think this is important to include, however obvious it is to some

---

From: Lars Eggert <[email-masked]>
Date: Thu, 13 Sep 2007 14:28:14 +0300

Hi, Bruce,

On 2007-9-12, at 17:04, ext Bruce Davie wrote:
> clarification, but we don't want to surprise anyone. The proposed  
> new text, which would appear at the end of Section 6, is included  
> below:
>
> packets of a single microflow should always travel on the same LSP  
> to avoid possible misordering. Thus, ECN marking of packets on L- 
> LSPs SHOULD only affect the EXP value of the packets.

thanks for the heads-up. This clarification seems fine to me.

(I'm cutting things from your reply that I agree with.)

> In my mind, section 8.3 is an example of how you can use ECN in  
> MPLS networks. I think the problem here is that we didn't say  
> enough to make that apparent. At the same time, I don't really see  
> any harm in dropping the section.

I'd prefer clarifying the example over removing it. If that's doable,  
great.

>> discussion of how one would use this to support PCN to an  
>> appendix. Some of this has happened, but Section 8.4 still exist  
>> in the main body of the document, and is longer than all the other  
>> example uses. I suggest to replace the content of Section 8.4 with  
>> a pointer to the appendix, and move the PCN details there.
>
> We certainly moved all the protocol details around PCN support to  
> an appendix as previously agreed. I have no problem moving most of  
> this section to an appendix too.

I'm not saying you should move all of it. Leave a sentence or two in  
Section 8.4, but move more of the details to the appendix. My basic  
concern was that there is still a lot of emphasis on the PCN usage  
example compared to the other ones, which could make it look as if  
PCN was _the_ intended usage, instead of one possible use case.

(I might be nitpicking here. If so, feel free to let me know.)

I tagged this as "Revised ID Needed" in the tracker. I fully expect  
the next revision that fixes these nits to directly go to IETF last  
call.

Lars