D-Link DFE-908X manual Topology, Network Diameter

Topology

A Fast Ethernet workgroup is configured in a star topology and is built around a maximum of two repeaters. Each workgroup forms a separate LAN (also known as a segment or collision domain), and these workgroups can be easily interconnected through switches, bridges, or routers to form one LAN large enough to encompass a high-rise building or campus envi- ronment. Recent innovations in LAN hub technology such as stackable hubs, coupled with the decreasing cost of switches, bridges, and routers, allow the design of low-cost, efficient Fast Ethernet workgroups and enter- prise LANs.

The following factors strongly influence the architecture of Fast Ethernet networks:

∙The EIA/TIA 568 Wiring Standard imposes a 100 meter limit on horizontal runs of twisted-pair cables; that is, connections from the wiring closet to the end-station.

∙Fast Ethernet’s increased operational speed reduces the maximum distance between all elements of the LAN (see below).

∙The EIA/TIA 568 Wiring Standard does not support the use of co- axial cables for horizontal wiring.

Network Diameter

Network diameter, which is the distance between two end-stations in the same collision domain, is the primary difference between traditional Ethernet and Fast Ethernet. Due to the increased speed in Fast Ethernet and adherence to the EIA/TIA 568 wiring rules, the network diameter of a Fast Ethernet collision domain is limited to 205 meters; in contrast, the maxi- mum 10BASE-T Ethernet collision domain diameter can be up to 500 meters.

6 Introduction