Nortel Networks 450 manual Redundant Cascade Stacking Feature

Using the BayStack 450 10/100/1000 Series Switch

•You can downline upgrade the entire stack from any switch in the stack.

•You can access and manage the stack using a TELNET connection or any generic SNMP management tool through any switch port that is part of the stack configuration.

•When stacking three or more switches, use the longer (1-meter) cascade max-return cable (PN 303979-A) to complete the link from the last unit in the stack to the base unit.

Redundant Cascade Stacking Feature

BayStack 450 switches allow you to connect up to 8 units into a redundant cascade stack. If any single unit fails or if a cable is accidently disconnected, other units in the stack remain operational, without interruption.

Figure 1-14 shows an example of how a stack configuration reacts to a failed or powered-down unit in the stack configuration:

1.As shown in Figure 1-14, unit 3 becomes nonoperational.

This can be the result of a failed unit, or simply because the unit was powered down.

2.Unit 2 and unit 4, directly upstream and downstream from unit 3, sense the loss of link signals from unit 3.

a.Units 2 and 4 automatically loop their internal stack signals (A and B).

b.The Cas Up LED for unit 2 and the Cas Dwn LED for unit 4 turn on (amber) to indicate that the stack signals are looped.

3.The remaining stack units remain connected.

Although the example shown in Figure 1-14 shows a failed unit causing the stack to loop signals at the points of failure (A and B), the system reacts the same way if a cable is removed.

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