Alcatel Carrier Internetworking Solutions 6600 User Manual

Configuring High Availability VLANs

page 3-6

Release 5.1.6.R02 User Guide Supplement

The figure below shows how ingress traffic is handled by high availability VLANs. 

In the above example, packets received on the ingress ports that are destined for the high availability 
VLAN MAC address are sent out the egress ports that are members of the same VLAN. Since all three 
servers are connected to egress ports, they all receive the ingress port traffic. This provides a high level of 
availability in that if one of the server connections goes down, the other connections still forward traffic to 
one of the redundant servers.

Note the following regarding ingress and egress port traffic flow:

• Ingress port traffic destined for the high availability VLAN MAC address is only sent out on egress 

ports and not on any other ingress ports.

• If a packet received on an ingress port is not destined for the high availability VLAN MAC address, the 

packet is bridged as regular traffic to all ports in the VLAN, not just egress ports.

• Traffic received on egress ports is bridged as regular traffic to all ports assigned to the VLAN, regard-

less of their ingress or egress port state.

One key application of high availability VLANs is interfacing with third-party high availability firewall 
clusters, which allow two or more servers running a common firewall application to work as if they were 
one system. The following subsection describes an example HA VLAN implementation that is used to 
interface with a third-party high availability firewall cluster.

OmniSwitch 7800