[67254] in North American Network Operators' Group
Re: Are SW upgrades needed in MPLS core networks?
daemon@ATHENA.MIT.EDU (Petri Helenius)
Fri Feb 6 14:05:07 2004
Date: Fri, 06 Feb 2004 20:55:00 +0200
From: Petri Helenius <pete@he.iki.fi>
To: "Rubens Kuhl Jr." <rubens@email.com>
Cc: Richard A Steenbergen <ras@e-gerbil.net>, nanog@nanog.org
In-Reply-To: <079301c3ece0$86ffb400$020ba8c0@NOTEBOOK>
Errors-To: owner-nanog-outgoing@merit.edu
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?
Pete
