Dell C1048P Port Extender Networking Command-Line Reference Guide for the C900 - Page 577

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 show ip protocols - views information on all enabled and active routing protocols. bgp router-id Assign a user-given ID to a BGP router. C9000 Series Syntax bgp router-id ip-address To delete a user-assigned IP address, use the no bgp router-id command. Parameters ip-address Enter an IP address in dotted decimal format to reset only that BGP neighbor. Defaults The router ID is the highest IP address of the Loopback interface or, if you do not configure Loopback interfaces, the highest IP address of a physical interface on the router. Command Modes ROUTER BGP Command History Version Description 9.9(0.0) Introduced on the C9010. 9.2(1.0) Introduced on the Z9500. 8.2.1.0 Introduced on the E-Series ExaScale. 7.4.1.0 Introduced Usage Information Peering sessions are reset when you change the router ID of a BGP router. Border Gateway Protocol 577