Steven, as Fred and Brian alluded to, some of the Cisco routers use hardware acceleration to speed up the packet switching. I suspect however that your question was a more generic one, so I would suggest that you check this out:
http://www.cisco.com/en/US/tech/tk827/tk831/technologies_white_paper09186a00800a62d9.shtml I will also note that understanding the place of MLS might be a bit difficult without knowning the (rather horrifying :) details of the Catalyst architecture and its development history. It might help maintain your mental balance if you first gain a good understanding of how a router is supposed to work, and only then take a look at what the Catalyst is doing. :))) Thanks, Zsombor Steven Aiello wrote: > > Ok all I have a question on this subject. I know routing takes > place at > the network layer, and switching takes place at the data link > layer > because it works based on physical addresses. So how do we get > route > switching? I've just started my CCNP and we were learning > about > different cache methods to speed up performance, is this how > route > switching is done, is the routing calculation be performed on a > per > packet basis? I was reading that by default, Cisco routers > only perform > a routing calculation on the first packet for a destination > network and > then on less the no route-cache option is set all the rest of > the > packets are really only "switched" to the correct interface. > Am I > missing something? I would invision that a router would by > default > perform a lookup for each connection sequence. does layer 3 > routing not > do a look up for each sequence of packet? Does is look at an > address > and use an "old" pre say route that was cached in memory? If > some one > can give a good explanation I would greatly appreciate it. > > Thanks, > Steve > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=74819&t=74788 -------------------------------------------------- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
