13.5.1 Load-Balancing Configuration for VLAN Groups

GSRP manages the master and backup states of the switches for each VLAN group. A maximum of 64 VLAN groups can be configured on each GSRP switch. Permitting multiple VLAN groups and performing load balancing at the VLAN group level allows the GSRP switches to distribute the traffic load. The figure below provides an overview of load balancing.

In the example in the figure, Switch A is the master in VLAN group 1 and the backup in VLAN group 2. Switch B is the backup in VLAN group 1 and the master in VLAN group 2.

Figure 13-10: Load balancing configuration

When you use Layer 3 redundancy switching to balance the load, you need to provide a communication path between the GSRP switches to enable communication between the VLANs of the different master switches. This communication is performed by VLAN on the direct link shown in 13.5.3 Switching due to an upstream network failure when Layer 3 redundancy switching is used. The figure below provides an overview of load balancing when Layer 3 redundancy switching is used.

In this figure, Switch A is the master in VLAN 10 and Switch B is the master in VLAN 20. Traffic to the upstream IP network is forwarded by the master switch for each VLAN. The communication between VLAN 10 and VLAN 20 takes place via the VLAN on the direct link.

Figure 13-11: Load balancing configuration when the Layer 3 redundancy switching facility is used