North American Network Operators Group

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Re: Are SW upgrades needed in MPLS core networks?

  • From: Petri Helenius
  • Date: Fri Feb 06 14:44:39 2004

Rubens Kuhl Jr. wrote:

There is another factor at play here which is memory bandwidth at the
lookup engine. If you have to look deeper into the packet than you can
accomplish by using single spin trough the thing that fetches x bit wide
words from the packet, you�ll effectively half your packet rate.

Yes, that might explain the performance halving in some architetures (may be
it's what happens with Sup 720, may be not), instead of longer lookup cycle.

I have the understanding that catalyst line uses 48 bit access. Wonder where they got that from :-)

So when forwarding to single end hosts, you might end up with one third of the performance of IPv4. However I have not confirmed this but you might want to bother your sales engineer.

Doing 8+1+1+1+1+... would seem wasteful for IPv6 with the current
address allocation scheme, are you sure that�s what�s used for IPv6 too?

I'm not. Juniper isn't very open about this matter, and I only got
confirmation of that for IPv4.

I think they also put that in a public document, probably due to the fact that Cisco put theirs in first. I haven�t seen a document discussing structures either one uses for IPv6 but I have been told they are "different for performance reasons".