VRRP: Increasing Reliability and Failover with the Virtual Router Redundance Protocol

E.6. Explications for State Machine

While describing the behavior of the VRRP state machine in the backup and master states, the VRRP draft formulates some conditions that would require the handling or discarding of a received advertisement. The pseudocode explicitly states conditions under which the packets should be handled as part of an if clause, but since the discarding of the advertisement is subsumed under else-clause, the condition for this action is only stated implicitly. In this section we make these conditions explicit by following the logical equivalence of the negated if clause. Note that in both cases we assume that the priority of the received advertisement is not zero.

We also use our established symbolism in these discussions: ...