On Jul 26, 17:29, Shawn T. Rutledge wrote: They're often called "repeaters" which is actually a more accurate description. Yes, they are used to get over the length limitation (you can have up to 5 segments, connected by 4 repeaters, between any two hosts, though not all segents can be populated and there are rules about lengths, propagation delays, etc). They're also used to get over the number-of-hosts-on-a-segment limitation. However, they don't isolate collision domains; a collision on one segment will be faithfully copied to the others. -- Pete Peter Turnbull Network Manager University of York