Electing the Master Switch

A new master can be elected. This is done in one of the following ways:
  • A communicated parameter change

  • Loss of communication between master and slave(s)

If a parameter determines the master changes (for example, link loss or priority change), the election of the new master typically occurs within one second. A parameter change triggers a handshake between the routers. As long as both routers agree upon the state transition, new master election is immediate.

If a switch in slave mode loses its connection with the master, a new election occurs (using the same precedence order indicated ESRP Master Election or using a configured precedence order described in ESRP Election Algorithms). The new election typically takes place in three times the defined timer cycle (8 seconds by default).

Before the switch transitions to the master state, it enters a temporary pre-master state. While in the pre-master state, the switch sends ESRP PDUs until the pre-master state timeout expires. Depending upon the election algorithm, the switch may then enter the master or slave state. Traffic is unaffected by the pre-master state because the master continues to operate normally. The pre-master state avoids the possibility of having simultaneous masters.

To configure the pre-master state timeout, use the following command:

configure esrp esrpDomain timer premaster seconds



Configure the pre-master state timeout only with guidance from Extreme Networks support. Misconfiguration can severely degrade the performance of ESRP and your switch.