Subject: Comment for Request for guidance about the flow label

From: Yong Lucy <[email-masked]>
Date: Tue, 15 Jun 2010 16:46:53 -0500

Brian and Shane,

I read the draft. It is well written. Here are some comments: 

Text:

   o  At intermediate router(s) that perform ECMP or LAG for packets

      whose source address is a TEP, the hash SHOULD minimally include

      the triple {dest addr, source addr, flow label} to meet the

      [RFC3697] rules.  In practice, since the routers are assumed to be

      unaware of tunneled traffic, this means adding the flow label to

      the existing 5-tuple hash of the outer IP header.

   o  At intermediate router(s) that perform ECMP or LAG for packets

      whose source address is a TEP, the hash MUST minimally include the

      triple {dest addr, source addr, flow label} to meet the [RFC3697]

      rules.  In practice, since the routers are assumed to be unaware

      of tunneled traffic, this means intermediate router(s) SHOULD add

      the flow label to the existing 5-tuple hash of the outer IP

      header.

Two paragraphs are the same except one has "hash SHOULD" and another has
"hash MUST".

Text:

It might be possible to make this classifier stateless, by using a

      suitable modulo(N) hash of the inner IP header's 5-tuple as the

      pseudo-random value.

The document text uses N in referring N paths. It causes a confusion in
using modulo(N) here.  It should be modulo (2**20)

Regards,

Lucy

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From: Brian E Carpenter <[email-masked]>
Date: Fri, 18 Jun 2010 19:45:13 +1200

Lucy,

> I read the draft. It is well written. Here are some comments: 

...
> Two paragraphs are the same except one has "hash SHOULD" and another has

Oops.

> using modulo(N) here.  It should be modulo (2**20)

No, in the math notation I learned, modulo(N) is what we mean - the remainder
when the quantity is divided by N in integer artithmetic.

   Brian

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From: Yong Lucy <[email-masked]>
Date: Fri, 18 Jun 2010 08:31:20 -0500

snipped
> when the quantity is divided by N in integer artithmetic.
[LY] If this is the case, it is better explain that what does N mean here
because notation N occur several times in text and I think they refer to
different context.

Lucy