3Com 5017C-LS, 5017C with load sharing Backup Controller Module, Redundant Cable Links

Backup Controller Module

The controller is vital to the system because it performs important functions including:

❑synchronizing all modules

❑monitoring concentrator conditions (temperature, power supply status, etc.)

❑recognizing failures

❑clocking and timing to the ONline Concentrator backplane

By using two 3Com Fault-Tolerant Controller Modules (5000M-RCLS) in your concentrator you can protect these critical tasks if a controller fails.

Note: You cannot use the 5000M-RCTL or 5000M-CTL controller in a load-sharing concentrator (Model 5017C-LS or Model 5017C with load-sharing upgrade).

Redundant Cable Links

Cable breaks or failures are the most common problem in any network. Using the ONline Ethernet Fiber Module in your ONline System Concentrator enables you to implement full cable redundancy for your network's backbone. Thereafter, if one port should fail, or if a cable is disconnected or cut, the backup port will take over in 100 milliseconds. A sample redundant network connection is shown in Figure 1-6.

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