LAN cabling design for the new BLS building

The third generation of the cabling architecture for the local area network of the US Bureau of Labor Statistics in its new building is described. For each architectural element the design is described and the major alternatives are identified, and for each alternative the major tradeoffs are presented. The application of this architecture to the Bureau´s regional offices is discussed. The system is Ethernet-based. The cabling architecture consists of the following three elements: the central backbone segment, a number of primary distribution segments, and a much larger number of secondary distribution segments. The Name Service and other centralized LAN resources are connected to the central backbone segment. One end of each primary distribution segment is coupled to the backbone by a (MAC-level) bridge, and the other end is connected to one or more multiport repeaters. Currently the Bureau has about 1300 PC workstations connected to Ethernet LANs in Washington, DC and in its eight regional offices and hundreds of additional PCs are on order. Leased telephone lines connect all of the LANs together