Service Manual
Defaults Enabled
Command Modes ROUTER BGP (conf-router_bgp)
Command History
This guide is platform-specic. For command information about other platforms, refer to the relevant Dell
Networking OS Command Line Reference Guide.
The following is a list of the Dell Networking OS version history for this command.
Version Description
9.8(0.0) Introduced on the S3048–ON and S4048–ON.
9.7(0.0) Introduced on the S6000–ON.
9.0.2.0 Introduced on the S6000.
8.3.19.0 Introduced on the S4820T.
8.3.11.1 Introduced on the Z9000.
8.3.7.0 Introduced on the S4810.
7.8.1.0 Introduced on the S-Series.
7.7.1.0 Introduced on the C-Series.
7.6.1.0 Introduced
Usage Information
BGP uses regular expressions (regex) to lter route information. In particular, the use of regular expressions
to lter routes based on AS-PATHs and communities is common. In a large-scale conguration, ltering
millions of routes based on regular expressions can be quite CPU intensive, as a regular expression evaluation
involves generation and evaluation of complex nite state machines.
BGP policies, containing regular expressions to match as-path and communities, tend to use much CPU
processing time, which in turn aects the BGP routing convergence. Additionally, the show bgp
commands, which are ltered 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 — views information on all routing protocols enabled and active on the E-Series.
356
Border Gateway Protocol