Dell Force10 S55T FTOS Command Line Reference Guide for the S55 System FTOS 8. - Page 281

Command History Version 8.3.5.0 Version 7.8.1.0 Version 7.7.1.0 Version 7.2.1.0 Introduced on the S55. Introduced support on S-Series Introduced support on C-Series Introduced bgp regex-eval-optz-disable c e s 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 Command Modes Usage Information Enabled by default ROUTER BGP (conf-router_bgp) 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. Related Commands Command History 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. show ip protocols View information on all routing protocols enabled and active on the E-Series. Version 8.3.5.0 Version 7.8.1.0 Version 7.7.1.0 Version 7.6.1.0 Introduced on the S55. Introduced support on S-Series Introduced support on C-Series Introduced Border Gateway Protocol IPv4(BGPv4) | 281