Configuring High Availability VLANs
Release 5.1.6.R02 User Guide Supplement June 2005 page 3-5
High Availability VLAN Overview
High availability (HA) VLANs send traffic intended for a single destination MAC address to multiple
switch ports. This section provides a brief overview on how traffic flows in and out of high availability
VLANs and how high availability VLANs can manage third-party high availability firewall clusters (see
“High Availability Firewall Clusters” on page 3-6 for information).
An HA VLAN is configured by creating a standard VLAN and then assigning ingress or egress ports to
the VLAN. Once these types of ports are assigned, the standard VLAN automatically becomes an HA
VLAN. When this occurs, standard VLAN commands no longer apply.
Destination MAC addresses (unicast and multicast) are also assigned to high availability VLANs. These
addresses identify ingress port traffic that the switch will send out on all egress ports that belong to the
same VLAN
In addition to assigning ingress and egress ports, tagging inter-switch link ports with an HA VLAN ID is
allowed. Ingress port traffic destined for an HA VLAN MAC address is sent out on all egress and inter-
switch link ports that belong to the same VLAN. Traffic forwarded on inter-switch link ports is done so in
accordance with the Spanning Tree state of the port.
It is also possible to configure the ingress flood queue bandwidth size for HA VLANs. See “Configuring
the Flood Queue Bandwidth” on page3-15 for more information.
Note. Once a VLAN becomes an HA VLAN, only ingress, egress, and tagged inter-switch link ports are
allowed as members of that VLAN.