IBM 1PA, Operational, Installation, And Maintenance Manual

Page: 32 / 108

Describing the Physical Layout of the Fiber Optics
While the 7299 Multiplexer is a logical ring of devices, the fiber optic cables
interconnecting the Multiplexers can be a
Ÿ
Physical ring layout
Ÿ
Physical star layout
See Figure 2-3 and Figure 2-4 on page 2-7. If you require the maximum fiber
optic cable length from the 7299 Multiplexer specification, the physical ring may be
required to provide enough coverage. If the fiber optic cable run distance is not
great, a physical star layout provides for easier reconfiguration and troubleshooting.
See Table 2-2 on page 2-8.
Physical Ring Layout
The physical ring layout is made up of individual fiber optic cables or a pair of fiber
optic cables from host to remote, remote to remote, and then last remote to host.
This layout permits longer actual distances between locations. However, the
physical ring is more difficult to troubleshoot. Should a problem occur, the host
location is dependent on remote personnel to bypass a failing Multiplexer at that
site.
Figure 2-3. 7299 Multiplexer Ring Distribution
2-6
Planning, Installation, and Maintenance Guide