Hmmm,
You are right it
is confusing. I must have not had enough coffee that morning. Let me see if I
can clarify it for you.
The point I was trying to make is that there are
performance advantages to keeping the feedback values in order. For example if
my feedback list for the path A->B->C->D looks like this:
(A,B,Stuff1) (B,C,Stuff2) (C,D,Stuff3)
Then I can possibly
walk the list and my database structure simultaneously without having to start
the search from the root of some search tree every time. For example after
applying the (A,B,Stuf1) value to the database, when you apply (B,C,Stuff2) to
the database, you already have your pointers to 'B" so the search is
presumably much faster.
On the other hand, if the
feedback came in the order:
(A,B,Stuff1)
(C,D,Stuff3)
(B,C,Stuff2)
Then I have to look
from scratch for each link in the database without being able to take
advantage of where I previously was. Obviously that's going to be slower in
many implementations.
Now, I could have
written the draft to specify the vector as (A,Stuff)(B,Stuff)(C,Stuff)
and REQUIRED them to be sorted but that would have made it impossible to skip
feedback for certain links.
Hope this helps and
sorry my wordy description confused you.
Cheers,
Peter Ashwood-Smith
P.S. please, I don't want 20 emails saying not to
apply the feedback data to the topology database ... I simply said database,
its up to you where you store the data as long as you use it for interim route
computations but don't re-flood it, I'm happy.
-----Original
Message-----
From:
Bui, Khanh [SMTP:kbui@netplane.com]
Sent: Monday, November
06, 2000 3:34 PM
To: mpls@UU.NET
Subject: draft-ietf-mpls-te-feed-01.txt
Hello,
Would someone please clarify the recommended
order of
the feedback TLVs included in a
CR-LDP message as quoted
from section 2
"Adding feedback TLVs to CR-LDP":
"Two new TLVs are optionally added to the CR-LDP
mapping,
notification, and withdraw
messages. There may be an arbitrary
number of these TLV in any order or position in the message.
It is recommended that they be placed
such that they can be
read and applied to
override the topology database by scanning
the message forwards and walking the topology database from
the point where the last link feedback
TLV left off."
Specifically, what does the phrase "where the
last link
feedback TLV left off" mean
?
Thanks,
Khanh