Nortel Networks WEB OS 212777 - Manual (Page 280)

Web OS 10.0 Application Guide
280 n Chapter 11: High Availability
212777-A, February 2002
Assigning VRRP Virtual Router ID
During the software upgrade process, VRRP virtual router IDs will be automatically assigned
if failover is enabled on the switch. When configuring virtual routers at any point after
upgrade, virtual router ID numbers (
/cfg/vrrp/vr # /vrid ) must be assigned. The virtual
router ID may be configured as any number between 1 and 255.
Configuring the Switch for Tracking
Tracking configuration largely depends on user preferences and network environment. Con-
sider the configuration shown in
Figure 11-8 on page 263 . Assume that the user wants the fol-
lowing behavior on the network:
n
Web switch 1 is the master router upon initialization.
n
If Web switch 1 is the master and it has one active server fewer than Web switch 2, it
remains the master.
n
The user wants this behavior because running one server down is less disruptive than
bringing a new master online and severing all active connections in the process.
n
If Web switch 1 is the master and it has two or more active servers fewer than Web switch
2, then Web switch 2 becomes the master.
n
If Web switch 2 is the master, it remains the master even if servers are restored on Web
switch 1 such that it has one fewer or an equal number of servers.
n
If Web switch 2 is the master and it has one active server fewer than Web switch 1, then
Web switch 1 becomes the master.
The user can implement this behavior by configuring the switch for tracking as follows:
1. Set the priority for Web switch 1 to the default value of 100.
2. Set the priority for Web switch 2 to 96.
3. On both switches, enable tracking based on the number of virtual routers in master mode
on the switch and set the value = 5.
4. On both switches, enable tracking based on the number of healthy real servers behind
the VIP address that is the same as the IP address of the virtual server router on the
switch and set the value = 6.
Initially, Web switch 1 ( Figure 11-8 ) will have a priority of 100 (base value) + 5 (since it will
initially be the master) + 24 (4 active real servers x 6 per real server) = 129. Web switch 2 will
have a priority of 96 (base value) + 24 (4 active real servers X 6 per real server) = 120.