few comments on draft-ietf-tewg-interas-mpls-te-req-01.txt

[Yakov Rekhter <yakov@juniper.net>]

Folks,

Here are few comments on draft-ietf-tewg-interas-mpls-te-req-01.txt.

1. The document should state up front the following:

     This document doesn't make any claims with respect to whether
     it is possible to have a practical solution that meets all the
     requirements listed in this document.

With this in mind the following in 6.1 should be removed:

   It MUST meet all the requirements described in section 5 each 
   time a MUST is specified.

and be replaced with the following:

   It MUST document whether it meets each requirement described
   in section 5.

2. Since this is a *requirements* document, other than relying on the 
existing MPLS/DiffServ TE mechanisms, the document should not presume 
a particular solution. 

Therefore references to such specific solutions like PCS (e.g., in 
section 5.1.2) should be removed from the document. 

Ditto for the reference to Forwarding Adjacencies in 5.1.8.

Likewise, the following in 5.1.5 has to be removed:

   The solution SHOULD support the ability for intermediate nodes to
   signal the respective Head-End LSRs of the existence of a more
   optimal path.

(as it presuppose a particular way of establishing an optimal path).

3. In Section 5.1.3 the document needs to explicitly state whether
it is a requirement to maintain optimal path all the time, and if
not then what percentage of overall path life time.

4. Sections 6.2 ("Scalability and Extensibility"), 6.3 ("Complexity
and Risks"), and 6.5 ("Backward Compatibility") talk about requirements
on scalability and extensibility, and therefore should be moved
into Section 5.

5. I would suggest to include 5.1.8 into 6.2, as 6.2 talks about
scalability, and 5.1.8 talks about one particular aspect of scalability - 
scalability in the forwarding plane.

6. In 5.1.5 replace:

   Furthermore the solution SHOULD provide the ability of manually
   rejecting re-optimization at AS boundaries.

with the following:

   Furthermore, the solution MUST provide the ability to reject
   re-optimizatization at AS boundaries.

7. In 6.2 replace "SPF" with "Constrained SPF" or "CSPF".

Yakov.