Subject: AD review of draft-ietf-6man-flow-ecmp

From: Jari Arkko <[email-masked]>
Date: Sun, 19 Jun 2011 22:47:13 +0300

I have reviewed this draft. It is well written, justifies its 
recommendations and I believe it is ready to move forward. I have asked 
for an IETF Last Call. However, I did see one editorial issue and one 
technical issue that I would like you to discuss and correct if 
necessary (even during the Last Call):

> If there is a high
> proportion of tunnel traffic, traffic will not be distributed as
> intended across the paths between R1 and R2.
>   

... high proportion of traffic from one or small number of tunnels, 
traffic will not be ...

> * Intermediate IPv6 router(s) will presumably encounter a mixture
>   of tunneled traffic and normal IPv6 traffic.  Because of this,
>   the design may also include {protocol, dest port, source port}
>   as input keys to the ECMP and/or LAG hash algorithms, to
>   provide additional entropy for flows whose flow label is set to
>   zero, including non-tunneled traffic flows.  Whether this is
>   appropriate depends on the expected traffic mix and on
>   considerations of implementation efficiency.
>   

Really, I don't think we are constructing routers that could only route 
tunnel packets. A device such as a router needs to be capable of 
handling both tunnel and non-tunnel packets. Indeed, the router will in 
general not even be able to know if it is processing tunnel packets. I 
would recommend changing the above "may also include" to "should also 
include", and striking the last sentence.

Jari

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From: Brian E Carpenter <[email-masked]>
Date: Mon, 20 Jun 2011 10:33:31 +1200

Hi Jari,

Thanks for the review.

> ... high proportion of traffic from one or small number of tunnels,

OK

> include", and striking the last sentence.

Personally, I think you're right. Should that be a normative SHOULD?

We have a small handful of other minor edits that have come in since WGLC.
Do you want us to post a new version?

   Brian

---

From: Jari Arkko <[email-masked]>
Date: Mon, 20 Jun 2011 07:22:53 +0300

Brian,

> Personally, I think you're right. Should that be a normative SHOULD?

You were not using RFC 2119 language in this paragraph earlier either, 
so I don't think it is needed.

> Do you want us to post a new version?

Please do.

Jari