A Failed Chassis in an VSB Stacking System

If a chassis fails, there may be traffic disruption lasting several seconds as the system processes link down events and discovers the new topology.

Be aware that it is possible for a stack to be partitioned into separate operational segments. Should this happen, each segment operates as though it is a separate whole stack using the same IP address. The closed ring configuration will prevent separate partitions when a single point of failure occurs by assuring a daisy chain exists for all remaining chassis in the stack. A closed ring configuration is configured using interconnect links between the first and last chassis in the VSB stack.

Topology changes occur when a replacement chassis first joins the stack. Some traffic disruption may accompany these topology changes.

To replace a failed chassis in an VSB stacking system:

1. Remove the failed chassis taking note of the switch/routing, interconnect and uplink cabling that currently exists.
2. Before enabling VSB on the replacement chassis, assure that the replacement chassis has been loaded with the same firmware image loaded in the current system.
3. The configured bonded chassis-ID is associated with the physical chassis in memory. Clear the memory of the failed unit from the stack before configuring bonding for the replacement unit using the clear bonding chassis failed-chassis-ID command.
4. Configure the replacement chassis‘ VSB chassis ID and the ID of the VSB system to agree with the configuration of the failed chassis.
5. Optionally, on a two chassis VSB stacking configuration, enable bonding on 10GbE monitor ports.
6. Cable the replacement chassis with the cable configuration noted in step 1.
7. Restore the port level configuration by appending the configuration with the configuration from a previously stored configuration file when the chassis was operational within the stack, using the configure filename append command.
8. Enable bonding on the replacement chassis‘ 40GbE interconnect ports.
9. Globally enable the VSB system. The system is reset.
   

   Note

   If the bonded MAC address on each chassis is different (as provisioned by the network administrator), a host master election occurs resulting in a reset of all chassis except the elected host master.