Re: [Lsr] Tsvart last call review of draft-ietf-lsr-isis-rfc7810bis-03

["Les Ginsberg (ginsberg)" <[e-mail]>]

Yoshi -

Thanx for taking the time to review.

I can appreciate that this may the first time you have looked at RFC7810 - let alone the bis draft. As a result you have commented on content which is common to the bis draft and the RFC it is modifying (RFC 7810).

While your questions in isolation may be interesting, I believe they are out of scope for the review of the bis draft. What the bis draft is doing is addressing two modest errata - details of which can be found in https://tools.ietf.org/html/draft-ietf-lsr-isis-rfc7810bis-03#appendix-A
Comments on content not related to those changes is out of scope.

If you have an interest in this topic and want to comment on the substance of RFC 7810 and its companion document for OSPF RFC 7471, I encourage you to do so. Note that all of your comments (save the one on Security) are also applicable to RFC 7471 - so any agreed upon modification would need to be made to both documents. But I do not want to even start discussing such changes in the context of reviewing the bis draft changes. I hope you can understand why.

As regards your Security comment, I am not sure I understand what you are suggesting. As IGP info is flooded hop-by-hop, man-in-the-middle attacks have to be able to insert themselves on an IGP enabled link. Use of cryptographic authentication prevents untrusted sources from being accepted - which is the point being made.

   Les


> -----Original Message-----
> From: Yoshifumi Nishida <[e-mail]>
> Sent: Wednesday, December 05, 2018 11:12 AM
> To: [e-mail]
> Cc: [e-mail]; [e-mail]; [e-mail]
> Subject: Tsvart last call review of draft-ietf-lsr-isis-rfc7810bis-03
> 
> Reviewer: Yoshifumi Nishida
> Review result: Almost Ready
> 
> This document has been reviewed as part of the transport area review
> team's
> ongoing effort to review key IETF documents. These comments were written
> primarily for the transport area directors, but are copied to the document's
> authors and WG to allow them to address any issues raised and also to the
> IETF
> discussion list for information.
> 
> When done at the time of IETF Last Call, the authors should consider this
> review as part of the last-call comments they receive. Please always CC
> [e-mail] if you reply to or forward this review.
> 
> Summary: This document is almost ready for publication, but several points
> need
> to be clarified.
> 
> 1: In Section 1:
>      "While this document does not specify how the performance information
>      should be obtained, the
>       measurement of delay SHOULD NOT vary significantly based upon the
> offered
>       traffic load."
> 
>    It is not clear to me that why the measurement of delay should not vary
>    here. Also, queuing delay might be useful info to infer path status. Could
>    you elaborate the delays that the draft tries to capture?
> 
> 2: In Section 1:
>      "Thus, queuing delays SHOULD NOT be included in the delay
> measurement. "
> 
>    Is it clear for expected readers how to exclude queuing delays in their
>    measurements? Don't we need to provide any guidances or references
> here?
>    Also, what they should do if they cannot exclude it?
> 
> 3: In Section 2:
> 
>      "All values (except residual bandwidth) MUST be calculated as rolling
>      averages where the
>       averaging period MUST be a configurable period of time."
> 
>    This requirement is a bit different from the following texts in Section 5:
>    Also, does this mean only simple moving average must be used or any
> forms of
>    moving average is acceptable?
> 
>     "The values advertised in all sub-TLVs (except min/max delay and
>      residual bandwidth) MUST represent an average over a period or be
>      obtained by a filter that is reasonably representative of an average.
>      For example, a rolling average is one such filter."
> 
> 4: In Section 4.3:
> 
>     "This sub-TLV advertises the average link delay variation between two
>      directly connected IS-IS neighbors.  The delay variation advertised
>      by this sub-TLV MUST be the delay from the local neighbor to the
>      remote one (i.e., the forward-path latency)."
> 
>    Sorry.. I am not sure how to measure delay variation here. I think more
>    explanation is needed. It seems that it is not variance as the unit is sec.
> 
> 5: In Section 11:
> 
>     "The use of Link State PDU cryptographic authentication allows mitigation
>     the risk of man-in-
>      the-middle attack."
> 
>    When there is a risk for man-in-the-middle attack, don't we need more
> strong
>    requirements for the use of security mechanisms?
> 
> Thanks,
> --
> Yoshi