Handbook

N8406-023 1Gb Intelligent L3 Switch Application Guide 150
Active-Active redundancy
In an active-active configuration, shown in the following figure, two switches provide redundancy for each other,
with both active at the same time. Each switch processes traffic on a different subnet. When a failure occurs, the
remaining switch can process traffic on all subnets.
The following figure shows an Active-Active configuration example.
Figure 25 Active-Active redundancy
Extensions to VRRP
This section describes VRRP enhancements that are implemented in this switch:
Tracking VRRP router priority
The switch supports a tracking function that dynamically modifies the priority of a VRRP router, based on its current
state. The objective of tracking is to have, whenever possible, the master bidding processes for various virtual
routers in a LAN converge on the same switch. Tracking ensures that the selected switch is the one that offers
optimal network performance. For tracking to have any effect on virtual router operation, preemption must be
enabled.
The switch can track the attributes listed in the following table:
Table 24 VRRP tracking parameters
Parameter
Description
Number of IP interfaces on the switch that
are active (―up‖)
/cfg/l3/vrrp/track/ifs
Helps elect the virtual routers with the most available routes as
the master. (An IP interface is considered active when there is at
least one active port on the same VLAN.) This parameter
influences the VRRP router's priority in virtual interface routers.
Number of active ports on the same VLAN
/cfg/l3/vrrp/track/ports
Helps elect the virtual routers with the most available ports as
the master. This parameter influences the VRRP router's priority
in virtual interface routers.
Number of virtual routers in master mode on the switch
/cfg/l3/vrrp/track/vr
Useful for ensuring that traffic for any particular client/ server
pair is handled by the same switch, increasing routing efficiency.
This parameter influences the VRRP router's priority in virtual
interface routers.
Each tracked parameter has a user-configurable weight associated with it. As the count associated with each
tracked item increases (or decreases), so does the VRRP router's priority, subject to the weighting associated with
each tracked item. If the priority level of a standby is greater than that of the current master, then the standby can
assume the role of the master.
See ―Configuring the Switch for Tracking‖ for an example on how to configure the switch for tracking VRRP priority.
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