Failover Methods - Lenovo Flex System Fabric CN4093 Application Manual

Failover Methods

Intranet Clients
474
CN4093 Application Guide for N/OS 8.2
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. Traditionally, these
configurations have been hot‐standby configurations, where one switch is active
and the other is in a standby mode. A non‐VRRP hot‐standby configuration is
shown in the figure below:
Figure 59. A Non‐VRRP, Hot‐Standby Configuration
Client Switches
While hot‐standby configurations increase site availability by removing single
points‐of‐failure, service providers increasingly view them as an inefficient use of
network resources because one functional application switch sits by idly until a
failure calls it into action. Service providers now demand that vendorsʹ equipment
support redundant configurations where all devices can process traffic when they
are healthy, increasing site throughput and decreasing user response times when
no device has failed.
Lenovo N/OS high availability configurations are based on VRRP. The
implementation of VRRP includes proprietary extensions.
The Lenovo N/OS implementation of VRRP supports the following modes of high
availability:
Active‐Active—based on proprietary Lenovo N/OS extensions to VRRP

 Hot‐Standby—supports Network Adapter Teaming on your server blades
Primary Switch
IP: 200.200.200.100
Secondary Switch
IP: 200.200.200.101
A
Internet
Servers
B
NFS Server