Re: [mpls] MPLS-RT review of draft-osborne-mpls-extended-admin-groups-01

["Daniel King" <[e-mail]>]

Hi All, 

As a member of the MPLS-RT, I was asked to the review the following
document: 

Extended Administrative Groups in MPLS-TE
http://tools.ietf.org/html/draft-osborne-mpls-extended-admin-groups-01

The I-D looks to add a sub-TLV (IGP-TE) to provide for additional
administrative groups (AGs). The requirement is derived from the current
limit of 32 AGs. To extend beyond the 32 AG limit (Extended AGs - EAGs), the
I-D  proposes an OSPF/ISIS (TE) sub-TLV and an RSVP C-Type (Class 207).

Overall the draft is well-written and the solution proposal has been
documented. I think the document should be considered for WG adoption. 

A few areas that will require further discussion include: backwards
compatibility, advertising default values, and a few NITS. 

1. Backwards Compatibility
Within the network of nodes that support EAG and those that do not. Given
that AGs may already be widely used within the network. The author proposes
that if a node is advertising both the AG and EAG, then the first 32 bits of
the EAG must be identical to the advertised AG. Thus allowing the continued
use of AGs, even if nodes in the network are incapable of supporting EAGs.
This seems logical, but should be discussed and approved by users
(operators). 

2. Advertising Default Values
The I-D proposes that specified but not unadvertised EAG have a default
value of 0. This may differ from other vendor implementations of how they
treat unadvertised AGs. Further discussion would be required with vendors
who implemented AGs, and might be interested in implementing EAGs.   

Various NITs/suggestions:

3. There are a number of TBD ("To Be Discussed") and Editor Notes that need
to be either discussed, but in some cases just updated or removed. 

4. Use of Requirements Language should be checked, specifically uses of
"must", "shouldn't". 

5. Documenting Procedures and Error Handling. Although the I-D documents
what seems to be the necessary procedures in various scenarios, it may be
helpful (readability) to specifically highlight them in a procedures section
or sub-section.   

6. Maybe a paragraph or short sub-section providing motivation and context
would be helpful to the reader (i.e., why are 32 colors not sufficient for
today's networks?).

Br, Dan. 

-----Original Message-----
From: Loa Andersson [mailto:[e-mail]] 
Sent: 18 May 2013 19:51
To: Daniel King; Mach Chen; [e-mail]; Curtis Villamizar
Cc: [e-mail];
[e-mail]; VIGOUREUX, MARTIN
(MARTIN)
Subject: MPLS-RT review of draft-osborne-mpls-extended-admin-groups-01

Dan, Mach, Nic and Curtis,

You have been selected as MPLS Review team reviewers for
draft-osborne-mpls-extended-admin-groups-01.

Note to authors: You have been CC'd on this email so that you can know that
this review is going on. However, please do not review your own document.

Reviews should comment on whether the document is coherent, is it useful
(ie, is it likely to be actually useful in operational networks), and is the
document technically sound?  We are interested in knowing whether the
document is ready to be considered for WG adoption (ie, it doesn't have to
be perfect at this point, but should be a good start).

Reviews should be sent to the document authors, WG co-chairs and WG
secretary, and CC'd to the MPLS WG email list. If necessary, comments may be
sent privately to only the WG chairs.

Are you able to review this draft by June 3, 2013?

Thanks, Loa
(as MPLS WG chair)

-- 


Loa Andersson                        email: [e-mail]
Senior MPLS Expert                          [e-mail]
Huawei Technologies (consultant)     phone: [phone]