ESRP domains allow you to configure multiple VLANs under the control of a single instance of the ESRP protocol. By grouping multiple VLANs under one ESRP domain, the ESRP protocol can scale to provide protection to large numbers of VLANs. All VLANs within an ESRP domain simultaneously share the same active and standby router and failover router, as long as one port of each member VLAN belongs to the domain master.
Depending on the election policy used, when a port in a member VLAN belongs to the domain master, the member VLAN ports are considered when determining the ESRP master. You can configure a maximum of 64 ESRP domains in a network.
If you disable an ESRP domain, the switch notifies its neighbor that the ESRP domain is going down, and the neighbor clears its neighbor table. If the master switch receives this information, it enters the neutral state to prevent a network loop. If the slave switch receives this information, it also enters the neutral state.
ESRP packets do not identify themselves to which domain they belong; you either configure a domain ID or the ESRP domain uses the 802.1Q tag (VLANid) of the master VLAN.
A domain ID in the packet clearly classifies the packet, associates a received ESRP PDU to a specific ESRP domain, and tells the receiving port where the packet came from.
NoteActive Ports Count (ports): Total number of active physical ports of master VLANs of the ESRP domain.