106 Chapter 3: Switched/Campus LAN Solutions
ATM LANE can be substituted for Gigabit Ethernet, and so on. Modularity makes both
migration and integration of legacy technologies much easier. Troubleshooting is also
easier because the whole design is highly deterministic in terms of performance, path
determination, and failure recovery.
3
What changes could be made to ensure reliability and redundancy?
The distribution-layer switch shown in Figure 3-11 represents a point of failure at the
building level. Users in Area 1 (the left side of the figure) could lose their connections to
the backbone in the event of a power failure. If a link from a wiring closet switch to the
distribution-layer switch is disconnected, all users on a floor could lose their connections
to the backbone. Figure 3-12 shows a design that provides reliability and redundancy.
Figure 3-11
Proposed Topology at WeServeData
Workstations
Router
CAT 5000
L2 switch
CAT 5000
multilayer switch
Workstations
CAT 5000
L2 switch
CAT 5000
L2 switch
Workstations
Router
CAT 5000
L2 switch
CAT 5000
multilayer switch
CAT 5000
L2 switch
CAT 5000
L2 switch
87200333.book Page 106 Wednesday, August 22, 2001 2:18 PM