Extreme Networks Px Series - Manual (Page 92)

8-2 Px Series Application Switch Installation and Configuration Guide
The only difference between a traditional VRRP implementation and the Px series
application switch implementation is that instead of using the VRRP MAC address for a
single layer 3 router address, the Px series application switch uses the VRRP MAC
address for all VIPs configured in the system. Whenever the VRRP state changes, all
VIPs either start accepting traffic and making forwarding decisions, or stop doing so.
For VRRP to work, there must be a layer 2 adjacency between the application switches.
Each of the VLANs that are configured on the primary Px series application switch and
its adjacent layer 3 switch must be configured on the standby Px series application
switch and standby layer 3 switch. Additionally, depending on the configuration of the
application switch, the layer 3 switch needs some special configuration. This manual
assumes the layer 3 switch is running ExtremeWare.
Before configuring VRRP, make the following decisions:
• Select which system should initially be primary and which should be secondary.
Configure the secondary switch with a lower priority.
• Assign a virtual router ID (VRID), which must be the same on both systems. If
VRRP is being used by other devices on the same network, it is important to make
sure that the VRID is unique.
• Set a priority for each application switch.
• Decide whether to preempt or not preempt. If a transition occurs because the
primary (highest priority) device goes down, do you want it to take over from the
standby when it comes back up? This can cause unneeded network interruptions.
Adding and Configuring VRRPs
The highest priority device is selected as the primary. Priorities are in the range 1-255,
with a default priority of 100. You can change the priorities of a VRRP to trigger
failover. To set VRRP priority on the system, use the following command:
config vrrp vrid <number> priority <number>
To configure a VRRP to be the initial primary, use the following commands:
config vrrp add vrid <number>
config vrrp vrid <number> priority 255
enable vrrp
build
Give backup systems lower priorities: