|  | 7.5 | Effects of Layer 2 Devices on Data Flow
| 7.5.5 | Teaching topology segmentation by bridges, swithches, and routers
The teaching topology contains examples of segmentation by bridges, switches, and routers. Also in the teaching topology, many different parts of the network are brought together by the main router. The bridge divides the E1 Ethernet network into two segments. Traffic is filtered at the bridge, reducing potential collisions and the physical extent of the collision domain. Therefore, the bridge breaks the E1 Ethernet network into two segments: the first segment has the repeater and hosts K, L, M, N on it; the second segment has hosts O and P on it. This remains, however, a broadcast domain. The repeater extends the collision domain rather than segmenting it. The main switch divides the E0 Ethernet network into multiple network segments with each having guaranteed full bandwidth. The workgroup switch divides the workgroup segment into more segments. There are no broadcast domains on the segments off of the main switch or the workgroup switch. Also note that the switches provide high connectivity to their unshared bandwidth. The hub does not segment its part of the network. The hub and all the devices attached to it, all the way up to the main switch port, remain a collision domain. The router segments the entire LAN into two Ethernet subnetworks, which are segmented, and a Token-Ring and FDDI subnetwork, which by their nature, have no collision domains.