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PPP Multilink Reordering

Is reorder frame a concern in ppp multilnk connection? See output below, there are "5422515 reordered" which keeps incrementing every second, and there is a delay in connectivity. Just wondering if reorder is the cause, and what the reorder is?


sho ppp multilink

Multilink6, bundle name is group6

Bundle up for 1w0d

13 lost fragments, 5422515 reordered, 0 unassigned

0 discarded, 0 lost received, 9/255 load

0x1D98D8 received sequence, 0x13581 sent sequence

Member links: 2 active, 0 inactive (max not set, min not set)

Se1/0, since 1w0d, last rcvd seq 1D98D5

Se1/1, since 1w0d, last rcvd seq 1D98D7

Multilink7 (inactive)

Member links: 0

New Member

Re: PPP Multilink Reordering

I've been working a little bit with the PPP multilink concept. What I have found is that the 'reordered' message means exactly what it says: The router has reordered some frames. When you run multilink PPP, the ethernet frame get's choped up into two, or more, eaquel size PPP packets. These frames are then sent out on the PPP multilink. Each PPP packet is maked with a sequence number, so the recieveing end knows how to reassemble the ethernet frame form the PPP packets.

Let's say that the first PPP packet travels out on S1/0 and the second travels out on S1/1. If the second packet arrives on the other router first, the router has to wait(buffer) until the first packet arrives. This is called reordering. I guess, if you have a huge delay on the line, one of the lines has a higher delay than the other one, and because of this the router has to wait for the other packet to arrive before it can recreate the ethernet frame.


Re: PPP Multilink Reordering

Thank you. Yes we are checking the lines for delay or any other issues and trying to isolate the problem with one link which is what it seems here.

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