repeaters recreate signals to other segments, why not reflections?

Question

I've heard that repeaters don't amplify a signal, but that they recreate it. Are they only used on Ethernet networks and deal only with Ethernet frames? Does recreate the signal mean they repeat the 0's and 1's and have no idea about actual frames?

I've also read that you can connect two Ethernet network segments to repeaters, especially in the older technologies (10base2, 10base5?). And that when one segment has a break and gets reflection and brings down this segment that it doesn't affect the other segment. How does this happen? It would seem like it would simply repeat the reflections/ collisions to the other segment and bring down the other segment, it would seem to have some sort of intelligence, even though it is sometimes referred as a dumb device.

glen herrmannsfeldt · Accepted Answer

More or less, the bits are decoded, including reclocking, and then recreated on the other side.

There might be some that don't know about frames, but none that are part of the standard (that I know of).

In many cases, such as a break in the cable, a large number of collisions will be generated. Repeaters detect this and stop repeating the data until the problem is fixed. A short in the cable (shield to center conductor) will result in no data and no collisions. In that case, there is nothing to repeat.

It doesn't take much to realize that the collision rate is high. There is also jabber detection, when a sender sends much more than one packet without stopping.

-- glen

vlsidesign · Answer

Excellent.. thanks for the info._Gary

repeaters recreate signals to other segments, why not reflections?

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