Reference Guide

IPv6 Border Gateway Protocol (IPv6 BGP) | 809
bgp regex-eval-optz-disable
c e
Disables the Regex Performance engine that optimizes complex regular expression
with BGP.
Syntax
bgp regex-eval-optz-disable
To re-enable optimization engine, use the no bgp regex-eval-optz-disable command.
Defaults
Enabled by default
Command Modes
ROUTER BGP (conf-router_bgp)
Usage
Information
BGP uses regular expressions (regex) to filter route information. In particular, the use
of regular expressions to filter routes based on AS-PATHs and communities is quite
common. In a large scale configuration, filtering millions of routes based on regular
expressions can be quite CPU intensive, as a regular expression evaluation involves
generation and evaluation of complex finite state machines.
BGP policies, containing regular expressions to match as-path and communities, tend
to use a lot of CPU processing time, which in turn affects the BGP routing
convergence. Additionally, the show bgp commands, which are filtered through
regular expressions, use up CPU cycles particularly with large databases. The Regex
Engine Performance Enhancement feature optimizes the CPU usage by caching and
reusing regular expression evaluation results. This caching and reuse may be at the
expensive of RP1 processor memory.
Related
Commands
Command
History
bgp router-id
c e
Assign a user-given ID to a BGP router.
Syntax
bgp router-id ip-address
To delete a user-assigned IP address, enter no bgp router-id.
Parameters
show ip protocols View information on all routing protocols enabled and active on the
E-Series.
Version 8.3.19.0 Introduced on S4820T
Version 8.4.2.1 Introduced on C-Series and S4810.
Version 8.2.1.0 Introduced on E-Series ExaScale
Version 7.4.1.0 Introduced on E-Series TeraScale
ip-address
Enter an IP address in dotted decimal format to reset only that BGP neighbor.