|  | 1.1 | LAN Switching
| 1.1.2 | Why segment LANs?
A network can be divided into smaller units called segments. Each segment uses the Carrier Sense Multiple Access/ Collision Detection (CSMA/CD) protocol and maintains traffic between users on the segment. By using segments in a network, less users/devices are sharing the same 10Mbps when communicating to one another within the segment. Each segment is considered its own collision domain. This is an example of a segmented Ethernet network. The entire network has 15 computers (6 file severs and 9 PCs). Without segmenting the network all 15 devices would need to share the same 10Mbps bandwidth and would reside in the same collision domain. By dividing the network into three segments, a network manager can decrease network congestion within each segment. When transmitting data within a segment these five devices are sharing the 10Mbps bandwidth per segment. In a segmented Ethernet LAN data passed between segments is transmitted on the backbone of the network using a bridge, switch or router. The backbone network is its own collision domain and uses CSMA/CD to provide a best effort delivery service between segments.
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