Re: [Isis-wg] Stephen Farrell's No Objection on draft-ietf-isis-extended-sequence-no-tlv-05: (with COMMENT)

Stephen Farrell <stephen.farrell@cs.tcd.ie> Tue, 21 April 2015 17:07 UTC

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Date: Tue, 21 Apr 2015 18:07:36 +0100
From: Stephen Farrell <stephen.farrell@cs.tcd.ie>
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Subject: Re: [Isis-wg] Stephen Farrell's No Objection on draft-ietf-isis-extended-sequence-no-tlv-05: (with COMMENT)
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Hiya,

Thanks, that all sounds fine. No need to check back with me
specifically unless you feel it's useful.

Cheers,
S.

On 21/04/15 17:59, Uma Chunduri wrote:
> Hi Stephen,
> 
> Thanks for your comments. In-line [Uma]:
> 
> -----Original Message-----
> From: Stephen Farrell [mailto:stephen.farrell@cs.tcd.ie] 
> Sent: Tuesday, April 21, 2015 9:14 AM
> To: The IESG
> Cc: draft-ietf-isis-extended-sequence-no-tlv.shepherd@ietf.org; isis-chairs@ietf.org; chopps@chopps.org; draft-ietf-isis-extended-sequence-no-tlv.ad@ietf.org; draft-ietf-isis-extended-sequence-no-tlv@ietf.org; isis-wg@ietf.org
> Subject: Stephen Farrell's No Objection on draft-ietf-isis-extended-sequence-no-tlv-05: (with COMMENT)
> 
> Stephen Farrell has entered the following ballot position for
> draft-ietf-isis-extended-sequence-no-tlv-05: No Objection
> 
> When responding, please keep the subject line intact and reply to all email addresses included in the To and CC lines. (Feel free to cut this introductory paragraph, however.)
> 
> 
> Please refer to http://www.ietf.org/iesg/statement/discuss-criteria.html
> for more information about IESG DISCUSS and COMMENT positions.
> 
> 
> The document, along with other ballot positions, can be found here:
> http://datatracker.ietf.org/doc/draft-ietf-isis-extended-sequence-no-tlv/
> 
> 
> 
> ----------------------------------------------------------------------
> COMMENT:
> ----------------------------------------------------------------------
> 
> 
> - last para of section 5 (before 5.1) could do with a bit of a re-write, it's not very clear.
> [Uma]: Still working with Ben on this to address  his comment and shall confirm with you too after the change to see if it is any better.
> 
> - section 7: When this mechanism is used, can an attacker who can delete or re-order packets (which is v. similar to one who can replay
> packets) cause any new bad outcomes due to the verification of the out-of-order arrival? (Sorry, I don't know IS-IS enough to know the answer there, it's probably obvious.) If so, then maybe that argues that one ought note that this doesn't address such threats (but that this is still I guess worthwhile).
> 
> [Uma]: Out of ordered packets with lower sequence numbers would naturally be discarded by the receiving node. In that sense this feature actually helps for some 
>                 IS-IS PDUs where there is no  mechanism in place before this doc. But if the packets are deleted/not-forwarded then this mechanism can't mitigate  the situation. 
>                 This is kind of documented in https://tools.ietf.org/html/rfc6862#section-3.3 , I can state this particular aspect and refer the same in Section 7. 
>                Does this address your concern? Thx!
> 
>