Subject: Re: [Teas] Opsdir last call review of draft-ietf-teas-lsp-diversity-08

From: Dieter Beller <[email-masked]>
Date: Tue, 30 Jan 2018 10:07:31 +0100

Hi Ignas,

our apologies for the delayed response.

Please find attached revision 10 of draft-ietf-teas-lsp-diversity,
which has not been submitted yet.

All changes compared to revision 08 are still visible. Revision 09
has been submitted during IETF100 with some IESG review comments
incorporated.

Please find our replies to your comments below.

Could you please let us know whether your comments are adequately
addressed.

Thanks,

Dieter and co-authors

On 30.08.2017 11:23, Ignas Bagdonas
wrote:

Reviewer: Ignas Bagdonas
Review result: Has Issues

Hi there.

I have reviewed this document as part of the Operations Directorate's document
review process.

Overall the document seems to be heading in the right direction. There are some
issues related to clarity of RFC2119 language usage, especially less
restrictive forms and how that would relate to interoperability, the handling
of undefined values and errors, terminology could be aligned better to base
GMPLS and TE specifications.

see attached draft revision 10

The document does not cover manageability or
operational considerations at all - given that it is proposing protocol
extensions that require operator involvement, a section on operational
considerations and possible extensions to management models and procedures
should be covered. The Path-Key based signalling form seems to have interdomain
signalling related security aspects that would need to be looked a bit deeper.

We do not believe that neither the Path Key nor the PAS are forming
a security issue at domain boundaries as they are abstract
identifiers

that do not allow an another domain to infer anything about the
domain topology (link utilization for example) or the failure
situation in the

domain. Security considerations have been taken into account when
the solutions have been developed.

The document would benefit from terminology and acronyms section specific to
the proposed mechanism.

see attached draft revision 10

The larger comment on time scale and granularity aspects of SRLG aware path
calculation. The document is based on the assumption of a longer time period
between LSP signalling requests and path reoptimizations. What is the reason
for it, and what would be needed if the proposed solution is expected to
operate in closer to real time environment (minutes instead of weeks)? What is
the source of the time granularity restriction?

see attached draft revision 10 - the only timing requirement for the
solution is that the LSPs are established sequentially as opposed to
simultaneously.

Diversity information flooding specifics are stated as being out of scope. How
would that impact interoperability?

This I-D defines RSVP signaling extensions and routing information
exchange is therefore out of scope.

PAS identifier name space may be smaller or not comparable with SRLG group
identifier name space, is there a need to have any form of mapping mechanism in
place?

The PAS is an abstraction of SRLG information and the smaller name
space is therefore not an issue.

Small nits:

- Example based on figure 1 has got details wrong.

- Terms need to be consistent throughout the document - initiated/controlled is
used interchangeably, this seems to be coming from the merge of the 3 original
drafts.

- There is no "IPv4/IPv6" diversity identifier, they are separate per address
family and text should be expanded to describe them separately.

- Could the text describing the operation of L bit be simplified by stating
that L bit has the same semantics as in any other object - strict/loose hop
selection, and therefore diversity identifier is interpreted as a strict or
loose entity that MUST or MAY be taken into account?

see attached draft revision 10

There is a set of editorial nits and fixes throughout the document, a marked
version of the document is attached.

Thanks for the detailed review of draft-ietf-teas-lsp-diversity-08!
Please find attached the document with your comments and our replies

(draft-ietf-teas-lsp-diversity-08-comments-ibagdona-170829-final).