Service Manual

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 much 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.
Examples
Dell(conf-router_bgp)# no bgp regex-eval-optz-disable
Dell(conf-router_bgp)# do show ip protocols
Routing Protocol is "ospf 22222"
Router ID is 2.2.2.2
Area Routing for Networks
51 10.10.10.0/00
Routing Protocol is "bgp 1"
Cluster Id is set to 10.10.10.0
Router Id is set to 10.10.10.0
Fast-external-fallover enabled
Regular expression evaluation optimization enabled
Capable of ROUTE_REFRESH
For Address Family IPv4 Unicast
BGP table version is 0, main routing table version 0
Distance: external 20 internal 200 local 200
Dell(conf-router_bgp)#
Related
Commands
• show ip protocols — view information on all routing protocols enabled and active
on the E-Series.
bgp router-id
Assign a user-given ID to a BGP router.
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 no Loopback
interfaces are configured, the highest IP address of a physical interface on the router.
Command Modes ROUTER BGP
Border Gateway Protocol 459