13.2.1 Network Configuration

The following figure shows the basic network configuration when GSRP is used.

Figure 13-2: GSRP networking configuration

A switch configured with GSRP is called a GSRP switch. A pair of GSRP switches forms a GSRP group.In normal operation, one switch is the master switch and the other is the backup switch. The basic GSRP configuration consists of two GSRP switches and neighboring switches.

The two GSRP switches must be directly connected. This link is called a direct link.

On the direct link, control frames, called GSRP Advertise frames, are exchanged between the GSRP switches so the switches can check each other's status. Other data frames are blocked by default. If you want to send and receive data frames on the direct link, configure the GSRP VLAN group-only control functionality and use a VLAN that does not belong to any VLAN group or set the direct-link ports as ports not under GSRP control. When you use Layer 3 redundancy switching, the direct link might be used to relay ordinary data between the GSRP switches. In that case, use the GSRP VLAN group-only control functionality or configure the direct-link ports as ports not under GSRP control. For details, see 13.4 Layer 3 redundancy switching functionality and 13.5.3 Switching due to an upstream network failure in Layer 3 redundancy switching functionality.

The GSRP switches send and receive GSRP Advertise frames to check each other's status and to control the switchover between the master and backup states. The switchover between the master and backup states is performed for logical groups consisting of VLANs. These logical groups are called a VLAN groups.

The master GSRP switch forwards the frames from the specified VLAN groups, and the backup GSRP switch blocks the frames from the same VLAN groups.