Subject: RE: draft-ietf-mpls-te-feed-00.txt

From: "Peter Ashwood-Smith" <[email-masked]>
Date: Tue, 11 Jul 2000 08:53:43 -0500

Fair enough,

    I'll make the changes and reissue a new version of the document. 

    Peter

	-----Original Message-----
	From:	Alex Zinin [SMTP:[email-masked]]
	Sent:	Monday, July 10, 2000 1:34 PM
	To:	Ashwood-Smith, Peter [CAR:CS57:EXCH]
	Cc:	mpls
	Subject:	Re: draft-ietf-mpls-te-feed-00.txt

	Peter,

	You have several places in the document that explicitly speak
	about LSDB modification. Some examples below.
	I think this should be changed to something more neutral.

	>    constructed. Eventually this message arrives back at the source
	>    node, where the vector is taken and inserted into the topology
	>    database. This node has just learned from its mistake and is
now

	>    When the LDP session that originated a CR-LDP label request
receives
	>    a notification that contains feedback TLV's it is recommended
that
	>    these bandwidth values overwrite the corresponding values in
the
	>    nodes topology database. Doing so permits this node to
immediately

	Thanks,

	-- 
	Alex Zinin

	Monday, July 10, 2000, 7:15 AM, Peter Ashwood-Smith
<[email-masked]> wrote:

	>    Alex,

	>    Thanks for the comments. The thing to keep in mind here is that
how an
	> implementation chooses to store the feedback information is not
really part
	> of the draft, and does not need to be standardized. The important
point is
	> that you receive feedback and you use that feedback information in
	> subsequent computations until you get another LSA. There are a
variety of
	> different ways to accomplish this but probably the easiest is to
store
	> feedback information separately from flooded information. In any
case, fed
	> back information is never re-flooded, only the originator can
flood its
	> bandwidth information.

	>     If however you would prefer that I add a sentence or two  to
make this
	> more clear I will be happy to do so if you want to send me
something.

	>     Cheers,

	>     Peter

	>         -----Original Message-----
	>         From:   Alex Zinin [SMTP:[email-masked]]
	>         Sent:   Monday, July 10, 2000 1:59 AM
	>         To:     mpls
	>         Subject:        draft-ietf-mpls-te-feed-00.txt

	>           Peter, et al.

	>           In your draft you recommend to change the contents
	>           of IGP's LSDB whenever the feedback from the signaling
	>           component is received. I'm afraid it is not quite good.

	>           1. If the checksum of the LSA/LSP is not recalculated
	>              after the contents were changed, the IGP may report
	>              a fatal error if the checksum is verified before
	>              the next version of the LSA/LSP arrives.

	>           2. Recalculating the checksum is also wrong, because:

	>               a) only the originating router must do this

	>               b) if this is done by other routers it may affect
	>                  LSA/LSP version comparison algo.

	>           Because of the above and because it is a 'bad thing' to
	>           modify link-state PDUs originated by others, I think it
	>           is safer and makes some more sense to say that
implementations
	>           must account for a method to link the information
provided
	>           by the signaling component to the corresponding elements
	>           of the TE database, instead of overwriting it.

	>           Cheers,
	          
	>         -- 
	>         Alex Zinin