4.4 Thin Coaxial Physical Topology

Figure 4.2 shows two cable topologies that thin coaxial cable supports. A two-port repeater is shown connecting two thin coax segments. One of the thin coaxial segments is shown in the daisy chain topology, connected to DTEs 1, 2, and 3. By connecting the short cable pieces and BNC connectors together, you create the complete segment, which can link up to 29 stations and one repeater port, for a total of 30 MAU connections.

FIGURE 4.2 Thin Ethernet cable topologies

In the daisy chain topology, if anyone incorrectly removes a thin Ethernet coax segment from the BNC Tee connector on the back of their computer, the entire segment will stop working for all other computers. Removing the entire BNC Tee connector from the female BNC on the Ethernet interface will not disrupt the segment, however, since the entire length of the coaxial cable continues to function in that case.

The other segment is shown connected directly to one computer, DTE 4, and then terminating. This point-to-point segment supports only one computer, which limits the number of computers that can be affected by cable problems to the single machine on that segment.