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From: Daniel Bauer (DNBZURICH.IBM.COM)
Date: Tue Apr 03 2001 - 01:53:15 CDT
I fail to understand how this draft supports multiaccess links.
Consider the following scenario: routers R1, R2 and R3 are connected
to a switched ethernet N1. Then, the following directed links exist:
R1 -> N1, R2 -> N1, R3 -> N1 and
N1 -> R1, N1 -> R2, N1 -> R3.
All of those links may offer a different amount of available bandwidth.
Assuming that initially, each link offers 100 available bandwidth.
Assuming then that an LSP is set up from R1 to R2, consuming 10
and another LSP from R3 to R2, consuming another 20.
Then, the available bandwidth on each link is as follows:
R1 -> N1 : 90
R2 -> N1 : 100
R3 -> N1 : 80
N1 -> R1 : 100
N1 -> R2 : 70
N1 -> R3 : 100
From the draft, I get the impression that only the availabe bandwidth
for links R1->N1, R2->N1, R3->N1 are advertised, but not the ones from
N1->R1, N1->R2, N1->R3. Am I wrong here? Shouldn't the designated router
advertise TE info for the N1->Rx links? If the DR advertises N1->Rx
how does it compute the available bandwidth? If the DR does not
anything, how does R1 conclude that it has 90 avBw left to R3, but only
70 to R2?
Thanks in advance for your answers,