Subject: comment on latest draft-martini-l2circuit-encap-mpls-01.txt

From: "Shah, Himanshu" <[email-masked]>
Date: Fri, 16 Mar 2001 16:34:37 -0500

Hello Luca,

Sorry for the late comment, I didn't know of this draft until recently.
I see the addition of the control word and algorithm for handling
sequence numbers on send and receive side.

It seems that sequence check on receive side does not handle the 
wrap around correctly, i.e. finds the out-of-sequence little too late.

For example if the max was 64,

sender                   receiver's expected Seq

62          ->           62, next: 62+1=63
64          ->           63, 64>=63 packet in order. Next: 64+1=1, wrapped
63          ->           1, 63>=1 packet in order. Next: 63+1=64
1           ->           64, 1 !>=64. packet out-of-order, drop, next:1+1=2

As shown above, out-of-order packet already forwarded!

More later...

Himanshu Shah
Tenor Networks
Acton, MA