Failover Methods
Active-Active Redundancy
Virtual Router Group
© Copyright Lenovo 2016
With service availability becoming a major concern on the Internet, service
providers are increasingly deploying Internet traffic control devices, such as
application switches, in redundant configurations. ENOS high availability
configurations are based on VRRP. The ENOS implementation of VRRP includes
proprietary extensions.
In an active‐active configuration, shown in Figure
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.
For a configuration example, see "High Availability Configurations" on page
Figure 60. Active‐Active Redundancy
Internet
Internet
Enterprise
Routing Switch
The virtual router group ties all virtual routers on the switch together as a single
entity. As members of a group, all virtual routers on the switch (and therefore the
switch itself), are in either a master or standby state.
A VRRP group has the following characteristics:
When enabled, all virtual routers behave as one entity, and all group settings
override any individual virtual router settings.
All individual virtual routers, once the VRRP group is enabled, assume the
group's tracking and priority.
When one member of a VRRP group fails, the priority of the group decreases,
and the state of the entire switch changes from Master to Standby.
When VRRP group restrictions are enabled, advertisements for the group are
sent and received only on VRRP group interface.
Each VRRP advertisement can include up to 16 addresses. All virtual routers are
advertised within the same packet, conserving processing and buffering resources.
60, two switches provide
Active (subnet A and C)
Switch 1
Switch 2
Active (subnet B and D)
Chapter 39: Virtual Router Redundancy Protocol
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Servers
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