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

Uma Chunduri <> Tue, 21 April 2015 16:59 UTC

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From: Uma Chunduri <>
To: Stephen Farrell <>, The IESG <>
Thread-Topic: Stephen Farrell's No Objection on draft-ietf-isis-extended-sequence-no-tlv-05: (with COMMENT)
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Date: Tue, 21 Apr 2015 16:59:15 +0000
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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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Hi Stephen,

Thanks for your comments. In-line [Uma]:

-----Original Message-----
From: Stephen Farrell [] 
Sent: Tuesday, April 21, 2015 9:14 AM
To: The IESG
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

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for more information about IESG DISCUSS and COMMENT positions.

The document, along with other ballot positions, can be found here:


- 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 , I can state this particular aspect and refer the same in Section 7. 
               Does this address your concern? Thx!