Re: [OSPF] AD review of draft-ietf-ospf-prefix-link-attr-06

["Acee Lindem (acee)" <[e-mail]>]

Hi Alia,
Thanks for the review.

From: Alia Atlas <[e-mail]<mailto:[e-mail]>>
Date: Thursday, July 30, 2015 at 2:22 PM
To: "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>, OSPF WG List <[e-mail]<mailto:[e-mail]>>, shraddha <[e-mail]<mailto:[e-mail]>>
Subject: AD review of draft-ietf-ospf-prefix-link-attr-06

As is customary, I have done my AD review of draft-ietf-ospf-prefix-link-attr-06 before asking for IETF Last Call.  First, thank you very much for your hard work on this draft.  It is lovely to see needed work move quickly and have numerous interoperable implementations.

I do have a number of minor issues on the draft - but all on the level of clarifications.  Therefore, I have requested that IETF Last Call be started.  Assuming good responsiveness on the part of the authors, a revised version that addresses my concerns can be on the IESG telechat on August 20.

I do note that there are 6 authors on this draft.  Please provide input - since I know that you all well aware that the limit is normally at most 5.  One can identify a primary editor or two.  This isn't pure process; the more authors listed on a draft, the longer it takes to handle AUTH48 - particularly when some are not as involved and do not respond rapidly and with full context.  I make no judgement about the authors of this draft - who have clearly moved from pulling out the idea into a stand-alone draft and had a number of different implementations.

We’ve already made one pass on pruning the authors and since we are only one over, I’d like to leave it as is.



My review comments are below.   Thanks again for your hard work in getting this far!

Minor issues:

1) On p. 6, it says " AF Address family for the prefix.  Currently, the
only supported value is 0 for IPv4 unicast."  Please clarify VERY
CLEARLY why this restriction exists.  Not everyone reading this will
be familiar with support for IPv6 in various protocols and we are really
finally heading towards lots more IPv6.

I will clarify. There are basically two reasons. The first is that we really didn’t want to specify more than was necessary in this base document. The second is that we have OSPFv3 for IPv6. So, you may ask why we have this at all. The reason is that we didn’t want to rule out extension of OSPFv2 completely.




2) On p. 6 and 8.:
"The Instance field is an arbitrary value used to maintain multiple
Extended Prefix Opaque LSAs.  A maximum of 16777216 Extended Prefix
Opaque LSAs may be sourced by a single OSPF instance.": This doesn't
really give normative behavior.  I assume that what you mean is that
the advertising router has a number space for the Instance which has
no significance outside of that advertising router and can have
arbitrary values allocated from it.  Each of these LSAs is identified
uniquely by its Instance number.  Please provide good text for what
MUST be done and indicate that the value may be used for tie-breaking
("In this case, the Extended-Prefix-TLV in the Extended Prefix Opaque
LSA with the smallest Instance is used by receiving OSPFv2 Routers. ")
and there's an assumption that the values will be allocated from
smallest to largest.

I will clarify this. However, I don’t want to specify any assumption about allocation.



3) On p. 6 for the Route Type, it would be useful to have a reference to
where these type values are pulled from.  I'd also like to see some
text about whether other values could be valid in the future and how
so.  For instance, I'm assuming that you are basically pulling the
values from the OSPFv2 Link State (LS) Type
(http://www.iana.org/assignments/ospfv2-parameters/ospfv2-parameters.xhtml#ospfv2-parameters-5)
- so perhaps you could simply say so or clarify for what are valid
values.

Is there an example of referencing an IANA directory? I could also reference RFC 2823 and RFC 3101 directly.



4) On p. 9: For Link-Type, could you also put a reference to the IANA
registry?  I'd prefer it to be clear that if (unlikely as it seems)
there were a new Link-Type added, it would apply here too.

Sure. We’ll do the same.



5) In Sec 5, pleaes add an RFC Editor note that Section 5 will be removed
upon publication.  That's the intent wtih RFC 6982.  Thanks for
including this section in the draft.  If the information wants to move
to the OSPF WG wiki, that would give it a place to survive after this
draft is submitted to the RFC Editor.

Ok - I need to hunt down this OSPF Wiki we talked about in Prague as well.



Nits:

6) In Sec 2, there's an "e.g., mapping server deployment".  Could you add
a reference?  This tells me nothing...

Sure - it is the segment routing architecture document.



7) In Sec 2, In the packet format, could you clarify Opaque type = 7? Same
for on p.8 for opaque type = 8 ?

Sure.


8) Since you are creating the registry for the TLVs, please clearly state
that value 1 is being used earlier - instead of "suggested value" as
on p.9

Sure.

Thanks,
Acee



Regards,
Alia