VRRP behavior when a CPM FailOver occurs.

Products

• XOS

Issue/Introduction

Describes the events which occur when a CPM fails over in a VRRP configuration

Cause

Below are presented events which occur when a CPM fails over in a system configured for VRRP operation.

Resolution

Example configuration for below scenario is:
Chassis A - Two CPMs with CPM redundancy enabled and the CPMs are synchronized.
Chassis B - One or two CPMs.

Scenario assumes that there is no CPM role change on Chassis B.

The CPM fail-over process in a VRRP configuration is as follows:

1. The backup VRRP chassis (Chassis B) notices through VRRP messages that the primary CPM on the VRRP Master chassis (Chassis A) is not available while the secondary CPM on Chassis A starts all services to become primary CPM.
2. Chassis B (backup VRRP) becomes Master VRRP.
3. The secondary CPM in chassis A finishes starting all services, becomes primary CPM and starts to take part in VRRP.
4. If VRRP preemption has been configured, VRRP fail-back to the new Primary CPM in Chassis A occurs. If VRRP preemption has not been configured, Chassis B remains the VRRP Master.