45 CONFIGURING A STANDBY CENTER
This chapter covers the following topics:
■Standby Center Overview
■Configuring the Standby Center
■Displaying and Debugging the Standby Center
■Standby Center Configuration Examples

Standby Center

Overview To enhance a network's reliability, 3Com routers pr ovide perfect standby functions
through the use of standby centers
■Interfaces that have standby are called main interfaces. Every physical interface
or sub-interface on a router can serve as a main interface. A logic channel, such
as X.25 or frame-relay virtual circuits, on any interface can also serve as a main
interface.
■The interfaces serving as the standby for other interfaces are called standby
interfaces. Any physical interface or logic channel on an interface of a router
can serve as the standby interface of another interface or logic channel.
■One main interface can have several standby interfaces; if the main interface
goes down work resumes on a standby interface, based on priority.
■Interfaces (such as ISDN BRI and ISDN PRI interfaces) that have multiple physical
channels can provide standbys to multiple main interfaces by using dialer route.
Standby centers support the standby load sharing function. When the traffic of
the all-active interfaces on the standby center reaches the set enable threshold,
routers will start a standby interface with the highest priority to share the load
with the started interfaces. When the traffic of all active interfaces on the standby
center is less than the set disable threshold, routers close the standby interface
with the lowest priority.

Configuring the

Standby Center Standby center configuration includes:

■Entering the View of the Main Interface
■Specifying a Standby Interface and the Priority Used by the Main Interface
■Setting the Delay Time for Switchover between Main and Standby Interface
■Setting State-judging Conditions of the Logic Channel State
■Configuring Standby Load Sharing
Entering the View of the
Main Interface On a 3Com router, not only every physical interface or sub-interfaces of the router,
but every virtual circuit of X.25 or frame relay can work as a main interface. If the