At 06:11 PM 5/22/02, Kevin Jones wrote: >I was oblivious to the fact that I was using the word "subnet". What I >should have used is the word "segment".
Ah. That makes more sense. When a frame arrives, both bridges and switches send the frame on its way without sending it back onto the originating segment. If the bridge (switch) has learned which specific port to use, it sends the frame out just that port. If it hasn't learned yet, then it floods it out all ports except the originating port. That's the "unknown frames" that you mentioned in the first message. (It means "unknown destination," as in not knowing which port to use.) You get the picture, I'm sure, but it's still good to clarify the concepts. Priscilla >Anyway, I went back to what I >thought was the source and was unable to find the description I had read. >I'll look again. Not sure where I read it now. Anyway, this thread has >confirmed what I have always understood, ie. that switches are multiport >bridges. If I find that description again, I'll post it here for you to >take a look at. > > >""Priscilla Oppenheimer"" wrote in message >[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > At 02:58 PM 5/22/02, Kevin Jones wrote: > > >If a multiport bridge determines (based on the destination MAC address) >that > > >the destination node is on another subnet, > > > > Stop right there. It can't figure out that the destination is on a > > different subnet from the MAC address. Subnets are differentiated by > > network-layer information. MAC addresses are at the data-link layer. > > > > If the destination is on a different subnet, the destination MAC will be a > > router's MAC address, although the bridge (switch) wouldn't recognize that > > (unless it had some weird feature that did this, which is unlikely). If >the > > bridge (switch) has learned which port reaches that MAC address, then it > > will forward the frame out that port and no other. If it hasn't learned >how > > to reach that address yet, then it will flood the frame out all ports. > > > > Bridges and switches behave exactly the same. > > > > Priscilla > > > > > > > > > it will broadcast the frame out > > >all ports except the originating port. A switch, on the other hand, is > > >smart enough to only forward the frame out the destination port. Both > > >devices handle unknown frames and broadcasts the same way, ie. they will > > >forward the packets out all ports except the one the frame was received >on. > > > > > >Any thoughts? > > ________________________ > > > > Priscilla Oppenheimer > > http://www.priscilla.com ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=44765&t=44649 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
