High availability

Virtual router deployment considerations

Review the following issues described in this section to prevent network problems when deploying virtual routers:

•Assigning VRRP Virtual Router ID

•Configuring the Switch for Tracking

Assigning VRRP virtual router ID

During the software upgrade process, VRRP virtual router IDs are assigned automatically if failover is enabled on the switch. When configuring virtual routers at any point after upgrade, virtual router ID numbers (/cfg/l3/vrrp/vr #/vrid) must be assigned. The virtual router ID may be configured as any number between 1 and 250.

Configuring the switch for tracking

Tracking configuration largely depends on user preferences and network environment. Consider the configuration shown in the previous figure. Assume the following behavior on the network:

•Switch A is the master router upon initialization.

•If Switch A is the master and it has one fewer active servers than Switch B, then Switch A remains the master.

•This behavior is preferred because running one server down is less disruptive than bringing a new master online and severing all active connections in the process.

•If Switch A is the master and it has two or more active servers fewer than Switch B, then Switch B becomes the master.

•If Switch B is the master, it remains the master even if servers are restored on Switch A such that it has one fewer or an equal number of servers.

•If Switch B is the master and it has one active server fewer than Switch A, then Switch A becomes the master.

The user can implement this behavior by configuring the switch for tracking as follows:

1.Set the priority for Switch A to 101.

2.Leave the priority for Switch B at the default value of 100.

3.On both switches, enable tracking based on ports (ports), interfaces (ifs), or virtual routers (vr). You can choose any combination of tracking parameters, based on your network configuration.

NOTE: There is no shortcut to setting tracking parameters. The goals must first be set and the outcomes of various configurations and scenarios analyzed to find settings that meet the goals.

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