Hi Tomonori,
please see inline:
On 14/11/18 12:49 , Tomonori Takeda wrote:
Hello,
I have been selected as the Routing Directorate reviewer for this draft.
The Routing Directorate seeks to review all routing or routing-related
drafts as they pass through IETF last call and IESG review, and
sometimes on special request. The purpose of the review is to provide
assistance to the Routing ADs. For more information about the Routing
Directorate, please see
http://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDir
Although these comments are primarily for the use of the Routing ADs, it
would be helpful if you could consider them along with any other IETF
Last Call comments that you receive, and strive to resolve them through
discussion or by updating the draft.
Document: draft-ietf-ospf-ospfv3-segment-routing-extensions-17.txt
Reviewer: Tomonori Takeda
Review Date: Nov 14th, 2018
IETF LC End Date: Nov 16th, 2018
Intended Status: Proposed Standard
o Summary:
This document is basically ready for publication, but has nits that
should be considered prior to publication.
o Comments:
This document defines OSPFv3 extensions for Segment Routing with MPLS
data plane.
This document is mostly ready, but further clarification would be good
for better understanding of the protocol definitions (see below).
This document is well aligned with a related document
draft-ietf-ospf-segment-routing-extensions.
o Major Issues:
None
o Minor Issues:
1) Flooding Scope of SR-Algorithm TLV
In Section 4.1, it says:
"If the SR-Algorithm TLV appears in
multiple OSPFv3 Router Information Opaque LSAs that have different
flooding scopes, the SR-Algorithm TLV in the OSPFv3 Router
Information Opaque LSA with the area-scoped flooding scope MUST be
used."
At the same time, it say:
"For the purpose of SR-Algorithm TLV advertisement, area-
scoped flooding is REQUIRED."
So, does it mean a) a router MUST use area-scoped flooding for sending,
and
no. It says that that for the purpose of the SR-Algorithm TLV area scope
is required. That means it cannot be link-scope, but it can be
autonomous-system scope, because that is also covering the area-scope.
b) a router MUST support different flooding scopes for receiving?
SR-Algorithm TLV is sub-TLV of Router Information Opaque LSA, which can
be flooded in various flooding scopes - link, area, autonomous system.
The flooding scope is not specific to SR-Algorithm TLV, it is generic
one applicable to Router Information Opaque LSA.
2) LSA Type for OSPFv3 Extended Prefix Range TLV
In Section 5, it defines IA-Flag. It is not clear how this relates to
LSA type. Do we simply ignore LSA type being used to carry OSPFv3
Extended Prefix Range TLV?
I think we can remove this bit, given that we know the route type from
the LSA type itself. This was taken from the OSPFv2, where the Extended
Prefix LSA does not carry the type.
Will remove.
3) Meaning of SID/Index/Label in Prefix SID Sub-TLV
In Section 6, it says:
"SID/Index/Label: According to the V and L flags, it contains
either:
A 32-bit index defining the offset in the SID/Label space
advertised by this router.
A 24-bit label where the 20 rightmost bits are used for
encoding the label value."
I understand how V Flag relates to this selection, but it is not clear
how L flag relates to this selection.
L flag is not relevant, I will remove the reference to it.
Please let me know if you are fine with my responses.
thanks,
Peter
o Nits
None
Thanks,
Tomonori Takeda
.
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