The machines are connected via a Netgear DS108 dual speed hub. I think I understand what you are saying except for one thing. Does the speed get negotiated for every packet? If so, isn't there a lot of overhead? If not, how does a packet from a machine connected at 100mb get switched/routed to a machine connected at 10mb? Does it go through a "transformer"? It might help my understanding if I knew what was different about 10mb and 100mb ethernet other than the maximum throughput. For example, does 100mb use a greater frequency bandwidth, does it send more pulses per unit time, or what? I measured the throughput using ftp from a 1.0Gz PIII to a 400Mhz K6-3 and to a 750Mhz PIII. Mike > -----Original Message----- > From: tclug-list-admin at mn-linux.org > [mailto:tclug-list-admin at mn-linux.org]On Behalf Of Troy.A Johnson > Sent: Monday, November 19, 2001 8:58 AM > To: tclug-list at mn-linux.org > Subject: Re: [TCLUG] Co-living 100mb and 10mb ethernet > > > Mike, > > Here are my (not necessarily correct) answers: > > >>> mbresnah at visi.com 11/18/01 04:15PM >>> > >Could someone explain to me in a nutshell how 10mb and 100mb co-exist > >happily on the same ethernet? > > Technically, as stated before, they cannot. If your local > network is connected by a HUB, they are all on the > same ETHERNET SEGMENT. If your local network > is connected by a SWITCH, the switch provides a > separate a ethernet segment for each connection and > connects those with a BACKPLANE (which runs at > least as fast as the fastest network segment). Steve > explained dual speed hubs, but basically they provide > two ethernet segments: one 10Mb, one 100Mb; via an > internal two port switch. > > >For example, I have 3PCs and a DSL modem on > >my local network. 1 PC and the modem have 10mb cards and 2 of > the PCs have > >100mb cards. When I transfer a file from one of the 100mb > machines it takes > >about 5 times less time than when I transfer to the 10mb machine, so it > >certainly appears that the network is capable of both speeds. > Evidently the > >10mb is able to detect and handle collisions with the 100mb and > vice versa. > >Perhaps it's because they both use the same carrier frequency; > if they use > >such a thing? Also, is a 5x speed difference what I should expect? Not > >10x? > > The speeds are differentiated by a factor of 10 only > for the theoretical maximum throughput for each > medium. It may be difficult for your PCs to push a > 100Mb connection close to it's max. It may be that > the 10Mb connection is full duplex (actually 20Mb > max) while the 100Mb connection is half duplex. > A factor of 5 is not an unusual speed difference, > but it may depend on the service used (those with > less overhead (like FTP) will probably be faster). > > >Take pity on me. I'm a software guy. > I do pity you, Mike, and I pity me too. ;-) > > Troy > > _______________________________________________ > Twin Cities Linux Users Group Mailing List - Minneapolis/St. > Paul, Minnesota > http://www.mn-linux.org > tclug-list at mn-linux.org > https://mailman.mn-linux.org/mailman/listinfo/tclug-list