Subject: [mpls] Questions on draft-asm-mpls-tp-bfd-cc-cv

From: Greg Mirsky <[email-masked]>
Date: Fri, 12 Feb 2010 14:39:51 -0800

Dear Editors, Authors and All,
please find my comments and questions to the document below:

   - section 3.3 lists BFD states as UP, DOWN and INIT for p2p
   bidirectional, as well as, p2p and p2mp unidirectional LSPs. But Section 4.6
   of BFD for Multipoint Networks says that p2mp BFD State Machine doesn't have
   Init state (the diagram of the State Machine is in your document on page 7).
   - the last sentence of Section 3.3 says that a new BFD session initiated
   when an operator re-enables CC/CV monitoring. Though it might be an
   implementation issue, I think, that wording is not accurate, especially
   because unidirectional BFD doesn't have Init state. Can I propose to say "A
   BFD session is being brought up when the operator enables or re-enables the
   CC or CV/CC functionality on the same ME"
   - section 3.4.2 addresses issue of manipulating with BFD Discriminator
   value for MPLS-TP CV/CC. On the other hand, BFD for Multipoint Networks
   proposes to change demultiplexing process for unidirectional links, LSPs and
   to use source address in addition to Your Discriminator. Obviously, proposed
   format of CV/CC message doesn't use IP encapsulation and can not use
   procedure described in Section 4.8 of draft-katz-ward-bfd-multipoint-02 if
   leaf (egress) sends BFD control packet to root (ingress), i.e. in response
   to Poll. Since I could find reference to Poll function and believe that
   Timer Negotiation can be enabled, how the root/ingress LSR will demultiplex
   MPLS-TP CV/CC message sent from a leaf?

Regards,
Greg