On Mon, 19 May 2003, David S. Miller wrote: > I found a description of this thing on Cisco's web site. Amusingly it > seems to contradict itself, it says that the CEF FIB is fully > populated and has a 1-to-1 correspondance to the routing table yet it > says that the first access to some destination is what creates > CEF entries. > It seems to be done at interupt level sort of like Linux fast switching (not to be confused with CISCO fast switching); however, unlike Linux fast switching which looks up based on dst cache, they do lookups on a FIB with already nexthop entries (sort of like the hh cache we have). Theres something akin to a user land process which makes sure the neighbors are resolved all the time - most routing protocols stacks already do this today with BGP. I dont think Zebra does. What i am wondering is what if they have to do more than routing? Dont they end up with same (if not worse) effect? Having said all the above, i think it would be worth seeing what the effect of improving the slow path is (make it a multi-way trie). Actually before that someone needs to prove slow path is slow ;-> Note: It may make sense that we have options to totaly remove the cache lookups if necessary - noone has proved a need for it at this point. cheers, jamal - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
