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 14:07:17 2004

Rubens Kuhl Jr. wrote:

I don't get why Juniper and Cisco trie-lookup forwarding would differ in
comparing IPv4 and IPv6; Juniper does a 8+1+1+1+1+... search until a leaf
node is found, while Cisco does 16+8+8 (or something near it but still with
3 phases); for both architetures, IPv6 longer addresses implies walking more
deeply into the tree in order to find where to route.

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.

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?