Operating notes

  • VRRP advertisements not reaching the backups. If a master is forwarding traffic properly, but its backups are prevented from receiving the master's VRRP advertisements, both routers will operate in the master mode for the VR. If this occurs, traffic for the applicable gateway will continuously alternate between routers (sometimes called flapping.)

  • Deleting an IP address used to support a VR

  • VR limitsA VLAN allows up to 32 (16 for the 2930F switch) VRs, and a VR allows up to 32 IP addresses. This means that one VR can support up to 32 subnets. This capacity enables use of VRRP on all subnets in a VLAN that has more than 32 subnets.

  • Upgrading from VRRPv2Upgrading from a software version that only supports VRRPv2 retains the VRRPv2 mode.

  • Downgrading to a VRRPv2 software versionBefore downgrading to a software version that does not support VRRPv3, ensure that the active configuration does not include IPv6 settings. The downgrade is not supported if VRRP IPv6 settings are included in the active configuration file.

  • Proxy-ARP requests and MAC addressesThe following table shows which MAC address is returned in response to a proxy-ARP request.

Configured as:

Administratively:

Returns:

owner

Enabled

VRRP MAC address

owner

Disabled

Default VLAN MAC address

backup

Enabled, in master state

VRRP MAC address

backup

Enabled, not in master state

VRRP router does not respond to proxy-ARP request.

backup

Disabled

Default VLAN MAC address