Cisco Cisco IOS Software Release 12.2(22)S
Regex Engine Performance Enhancement
How to Change the Regular Expression Engine
3
Cisco IOS Release 12.0(26)S, 12.3(4)T, and 12.2(22)S
How to Change the Regular Expression Engine
Selecting the New Regular Expression Engine
We recommend that you use the new regular expression engine if you need to evaluate complex regular
expressions or if you have observed problems related to evaluating regular expressions. We recommend
that you use the default regular expression engine if you only use simple regular expressions.
expressions or if you have observed problems related to evaluating regular expressions. We recommend
that you use the default regular expression engine if you only use simple regular expressions.
Prerequisites
The regular expression engine can be selected only under a BGP routing process in router configuration
mode. So, the engine can be changed only after BGP has been enabled.
mode. So, the engine can be changed only after BGP has been enabled.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
router bgp as-number
4.
bgp regexp deterministic
5.
exit
DETAILED STEPS
Command or Action
Purpose
Step 1
enable
Example:
Router> enable
Enables privileged EXEC mode.
•
Enter your password if prompted.
Step 2
configure
terminal
Example:
Router# configure terminal
Enters global configuration mode.
Step 3
router bgp
as-number
Example:
Router(config)# router bgp 1
Enters router configuration mode, and creates a BGP
routing process.
routing process.