Re: [secdir] secdir review of draft-ietf-mpls-tp-oam-analysis-08

["Sprecher, Nurit (NSN - IL/Hod HaSharon)" <[e-mail]>]

Tina hi,
Thank you for your review.
Please see inline.
Best regards,
Nurit
 
-----Original Message-----
From: ext Tina TSOU [mailto:[e-mail]] 
Sent: Saturday, March 24, 2012 8:11 AM
To: [e-mail]; [e-mail]
Subject: secdir review of draft-ietf-mpls-tp-oam-analysis-08
 
I have reviewed this document as part of the security directorate's
ongoing effort to review all IETF documents being processed by the IESG.
These comments were written primarily for the benefit of the security
area directors.  Document editors and WG chairs should treat these
comments just like any other last call comments.
 
Some comments which may not be from security aspects only are below.
 
1) One missing OAM function
 
I compared the OAM functions listed in this draft and those required in
RFC5860 and find out one OAM function named Client Failure Indication
(Section 2.2.10 of [RFC 5860]) is missing. I cannot see a reason for
this. Since this is an informational analysis document, it is
recommended to give a whole view. Specific clarifications are
appreciated in the document. 
 
<Nurit> this document provides an overview of the MPLS-TP OAM tools that
are specified in separate RFCs. It was agreed by the working group that
the final version of this document refers to RFCs only.
draft-ietf-mpls-tp-csf on "Indication of Client Failure in MPLS-TP" was
expired on September 2011, hence we cannot refer to this document. 
Please note also that although the name of the FILE may confuse, this
document does not make any analysis but rather presents an overview of
the OAM tools. The purpose of the document is carried in the document
TITLE and Abstract/Introduction. \<Nurit>
 
 
2) Lack of analysis about the compatibility with existing tools
 
It is said in this document that compatibility with the existing tools
has been maintained. But there is no detailed analysis which IMHO might
be of great interest to the industry and should form an important part
of this analysis document.
 
<Nurit> 
As mentioned above, the purpose of the document is to provide an
overview of the MPLS-TP OA tools. It is not a detailed analysis of the
tools. 
Still, I think your idea is excellent, and may be a subject for another
I-D. \<Nurit>
 
3) 1.1 Scope
 
In the middle of this section, under the "three objectives", the first
bullet reads  
 
   o  The OAM toolset should be developed based on existing MPLS
      architecture, technology, and toolsets.
 
However, in the following paragraph it is written as
 
   o  ITU-T OAM for Ethernet toolset as defined in [Y.1731].  This has
      been used for functionality guidelines for the performance
      measurement tools that were not previously supported in MPLS.
 
There seem to be conflicts between the objective (should...existing
MPLS....) 
<Nurit> I am afraid I cannot see the conflict between the sentences....I
consulted with some colleagues and they could not see the conflict as
well. \<Nurit>
and the toolset development (...tools...not...supported in MPLS). [RFC
5860] says that "...the MPLS-TP design, SHOULD as far as reasonably
possible, reuse existing MPLS standards." which looks more appropriate
to me as the objective. Please clarify this point.
 
 
4) 1.1 Scope
 
The third one of the "three objectives" in this draft reads 
 
   o  The OAM toolset developed for MPLS based transport networks needs
      to be fully inter-operable with existing MPLS OAM tools as
      documented in [RFC 5860].
 
I may be wrong but I find [RFC 5860] only requires OAM interoperability
between distinct domains (w/wo IP capabilities). The original
description is as follows:
 
   It is REQUIRED that OAM interoperability is achieved between distinct
   domains materializing the environments described in Section 2.1.4.
My understanding of the "OAM interoperability" mentioned here refers to
MPLS-TP OAM interoperable in different domains, but not MPLS-TP OAM and
MPLS OAM interoperability. 
 
<Nurit> Section 2.1.4 to which you refer in your quote, discusses the
environments. 
"There are environments where IP capabilities are present in the data
plane.  IP/MPLS environments are examples of such environments....".
RFC 5860 continues to require that "When MPLS-TP is run with IP routing
and forwarding capabilities, it MUST be possible to operate any of the
existing IP/MPLS and PW OAM protocols (e.g., LSP-Ping [4], MPLS-BFD
[13], VCCV [5], and VCCV-BFD [14])."
\<Nurit>
 
 
5) MPLS-TP v.s. MPLS based transport networks
The draft uses both "MPLS-TP" and "MPLS based transport networks". E.g.
is it "MPLS-TP OAM" or OAM toolset developed for MPLS based transport
networks? 
Are they the same? Or what is the relationship between them?
 
<Nurit> thank you for catching this. We will clarify that they are the
same. \<Nurit> 
 
Tina