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