In message <[EMAIL PROTECTED]> Erblichs writes: > > > The biggest reason for this is because the forwarding > tables need faster memory. If we assume that forwarding > table memory is 4x faster than routing table memory,
Nice try but ... The forwarding memory is on another card in a reasonably big router and therefore the information has to be trasferred from one processor to another and then installed in the forwarding memory. Also the forwarding memory is primarily used for forwarding and in a big busy router not too many cycles are left over for the writes that update the forwarding memory due to the reads that are occurring concurrently. In some architectures this is minimized. For example, some may use memory caching techniques others dual memory banks, etc. But perhaps the biggest factor is that the few hundred or few thousand IGP routes are the basis for BGP next hops so after they are computed the few 100,000 BGP routes and forwarding entries are mapped onto the SPF results. Since there are usually more than 100 times as many BGP routes as IGP routes doubling the speed of the SPF has no effect. In any case, Dave is right. The SPF typically takes far less time than the things that happen as a result of the SPF. Curtis ps - OTOH the speed of the MPLS/TE CSPF is very significant. _______________________________________________ OSPF mailing list [email protected] https://www1.ietf.org/mailman/listinfo/ospf
