Re: [RRG] Idea for shooting down

[Tony Li <tli@cisco.com>]

On Nov 28, 2007, at 2:51 PM, HeinerHummel@aol.com wrote:

A single matrix lookup for any destination which is still in a different geo-patch can also be done by ASIC.

True, that should be a straightforward array lookup.

Can anybody tell the difference in time compared with prefix lookup by ASICs ?

Yes, the longest-match would be much, much slower.  ;-)

In any non-trivial forwarding table, the longest-match will require multiple memory reads.  Exactly how many is very much a function of the specific lookup algorithm.  In a naive v4 implementation, you could reasonably take around 24 memory reads.  However, the array lookup should be just a single read.

Tony