Avaya 4000 Series Troubleshooting Instructions page 32

Troubleshooting tools
Figure 5: Wiring Closet Deployment 1
In the following scenario, the non-base unit continues to use the stack IP address. A gratuitous
ARP is issued by the non-base unit to update ARP caches throughout the network. Clients
connected to the non-base unit still have connectivity to the network.
Figure 6: Wiring Closet Deployment 2 – Failure Scenario 1
In the following scenario, the base unit continues to use the stack IP address. It issues an ARP
request to update the ARP cache throughout the network. Clients connected to the base unit
maintain network connectivity.
Figure 7: Wiring Closet Deployment 2 – Failure Scenario 2
In the following scenario, if functioning in Stack Forced Mode, both devices use the previous
stack IP address. Each device, to detect if the previous stack partner also uses the previous
stack IP address, issues an ARP request on that IP address before using it. In the scenario
where the stack of two is connected to the router through an MLT, both of these devices
continue using the same IP address. If the switch connects to the core routing switch through
LACP, the two links are not aggregated and the problem does not arise.
32 Troubleshooting Avaya ERS 4000 Series
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April 2014