Cisco Systems OL-7396-01 Configuring Fault-Tolerant Operation

14-15
ATM Switch Router Software Configuration Guide
OL-7396-01
Chapter14 Configuring LANEmulation
LANE Configuration Tasks
Configuring Fault-Tolerant Operation
The LANE simple server redundancy feature creates fault tolerance using standard LANE protocols and
mechanisms. If a failure occurs on the LECS or on the LES/BUS, the emulated LAN can continue to
operate using the services of a backup LES. This protocol is c alled the Simple Server Redundancy
Protocol (SSRP).
For a detailed description of SSRP for LANE, refer to the Guide to ATM Technology.
Enabling Redundant LECSs and LES/BUSs
To enable fault tolerance, you enable multiple, redundant, and standby LECSs and multiple, redundant,
and standby LES/BUSs. This allows the connected LANE components to obtain the global list of LECS
addresses. Our LANE continues to operate seamlessly with other vendors’ LANE com ponents, but fault
tolerance is not effective when other vendors’ LANE components are present.
To configure multiple LES/BUSs for emulated LANs on the routers or switch routers, perform the
following steps, beginning in global configuration mode:
Server redundancy guards against the failure of the hardware on which LES components are running.
This includes all the ATM interface cards in our routers and Catalyst switches. Fault tolerance is not
effective for ATM network or switch router failures.
Caution For server redundancy to work correctly, all ATM switch routers must have identical lists of the global
LECS addresses, in the identical priority order. The operating LECSs must use exactly the same
configuration database.
Load the configuration table data using the configurenetwork command. This method minimizes errors
and enables the database to be maintained centrally in one place.
For examples of these commands, see LANE Configuration Examples, page 14-17.
Implementation Considerations
For important considerations when implementing SSRP, refer to the LANE discussion in the Guide to
ATM Technology.
Command Purpose
Step1 Switch(config)# lane database database-name
Switch(lane-config-database)#
Creates a named database for the LECS.
Step2 Switch(lane-config-database)# name elan-name
server-atm-address address index n
Specifies redundant LES/BUSs, or simple server
replication. Enter the command for each LES
address for the same emulated LAN. The index
determines the priority. The 0 is the highest
priority.
Step3 Switch(lane-config-database)# lane client
{ethernet | tokenring} elan-name
Enables a LANE client for the first emulated
LAN. (The tokenring option is not supported on
the Catalyst 8540 MSR.)