Re: [mpls] poll on making draft-zhao-mpls-ldp-multi-topology-02.txt an mpls wg document

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

Hi WG,

Just wanted to add my support for the work/document.

Authors,  I have also reviewed the document. I can provide an MS word
document with change modification indicators  to the current editor(s). In
the meantime here are a number of comments and suggestions. Assuming the
document is adopted, these suggestions might be incorporated after the ID is
submitted as draft-ietf. 

1. Solution Comments

Having spoken to various vendors and operators I believe the preferred
solution is to extend MPLS for MT networks by mapping an IP address to the
corresponding Multi Topology:

Single topology label ~ address
MT label ~ (address plus topology)

This would negate the need for changes at the data plane.  Then the only
mapping required is at the ingress-PE of an MPLS-MT LSP, each node would be
capable of identifying the MPLS-MT LSP, and traffic is switched accordingly
based on the incoming label information. This solution uses minimal protocol
extensions. 

Please find my suggested updates and fixes for the first half of the
document. 

1. Document editors, table of contents  and formatting

- ChinaMobile/China Mobile
- Verison/Verizon
- Unnecessary number of CRs between authors and document title/name. 
- FEC TLV with MT-ID Extenstion/FEC TLV with MT-ID Extension

2. Revised Abstract

>>
Multi-topology (MT) routing is supported in IP through extension of IGP
protocols, such as OSPF and IS-IS.  It would be advantageous to extend
Multiprotocol Label Switching (MPLS), using Label Distribution Protocol
(LDP), to support multiple topologies. These LDP extensions, known as
Multiple Topology Label Distribution Protocol (MT LDP), would allow the
configuration of multiple topologies within an MPLS LDP enabled network. 

This document describes the protocol extensions required to extend the
existing MPLS LDP signalling protocol for creating and maintaining LSPs in
an MT environment.
<<

Line 34: enviroment/environment

3. The introduction, as well as other areas of the document, could do with
significant weight loss. Although interesting, some of the text is redundant
in this document. I would suggest the introduction is slimmed down to the
following text/edits, and a new requirements section (see comment 4) is
added:

>>
OSPF and IS-IS use MT-ID (Multi-Topology Identification) to identify
different topologies.  For each topology identified by a MT-ID, IGP computes
a separate SPF tree independently to find the best paths to the IP prefixes
associated with this topology. 

For FECs that are associated with a specific topology, this solution
utilises the same MT-ID of this topology in LDP.  Thus LSP for a certain FEC
may be created and maintained along the IGP path in this topology.

Maintaining multiple MTs for MPLS network in a backwards-compatible manner
requires several extensions to the label signaling encoding and processing
procedures.  When label is associated with a FEC, the FEC includes both IP
address and topology it belongs to.
<<

Line 204: certian/certain

Line 238: managment/management

Line 241: forwarding/forwarding

Line 251: tolology/topology

Line 253: assinged/assigned

Line 256: prtoco/protocol

Line 260: distingushed/distinguished and assinged/assigned

4. Requirements, specifically the lack thereof. The document would benefit
from a paragraph with bullets detailing the objectives/requirements for
these protocol extensions. 

5.  Application Scenarios are useful but specific requirements can be
blended into the requirements section. 

Thanks,
Dan

-----Original Message-----
From: [e-mail] [mailto:[e-mail]] On Behalf Of Loa
Andersson
Sent: 20 September 2011 19:16
To: [e-mail]; [e-mail]
Subject: [mpls] poll on making draft-zhao-mpls-ldp-multi-topology-02.txt an
mpls wg document

Working Group,

this is to start a two week poll to see if there is support to make

     LDP Extension for Multi Topology Support
     draft-zhao-mpls-ldp-multi-topology-02.txt

an MPLS working group document.

Send your opinions to [e-mail]

Please remember that it is particular important that you include a technical
motivation if you don't want the ID to become a working group document.

The poll ends Wednesday Oct 5, 2011.

/Loa
for the MPLS wg co-chairs


-- 


Loa Andersson                         email: [e-mail]
Sr Strategy and Standards Manager            [e-mail]
Ericsson Inc                          phone: [phone]
                                              [phone]
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