Specifications

Ethernet Repeaters
6-4 Ethernet Devices
Figure 6-5 shows a Cabletron Systems LR2000 two-port local Ethernet
repeater.
Figure 6-5. Cabletron Systems Two-Port Local Ethernet Repeater
Repeaters and Collisions
A collision happens when more than one station transmits on the network
at one time. Since the repeater physically separates the two coaxial
segments, a collision on one segment cannot be seen by devices on the
other segment connected to the repeater. Therefore, the repeater is
responsible for ensuring that the collision signal is propagated to all
segments attached to it. To force a collision, the repeater sends out a
special bit pattern called a Jam signal to all segments attached to it. This
signal notifies all stations on the network that a collision has occurred.
Auto Partition
When the repeater detects 32 consecutive collisions on one port it will
logically turn off or segment the port that it detected the problem on, thus
allowing the rest of the network to function properly. When the repeater
detects a collision on the segmented port, the collision will not be
forwarded to the other segments of the network, leaving the port in
segmented condition. When the repeater receives a packet on a good port,
it attempts to transmit the packet to the segmented port. If the packet
transmits successfully, the repeater will turn the segmented port back on,
bringing it out of segmentation.
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