Dell Command Line Reference Guide for the S4048–ON System 9.14.2.8

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bgp regex-eval-optz-disable

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
Command Modes
ROUTER BGP (conf-router_bgp)
Command History

This guide is platform-specific. For command information about other platforms, see the relevant Dell EMC Networking OS Command Line Reference Guide.

Version
Description
9.10(0.1)
Introduced on the S6010-ON and S4048T-ON.
9.10(0.0)
Introduced on the S3148.
9.10(0.0)
Introduced on the S6100-ON.
9.8(2.0)
Introduced on the S3100 series.
9.8(1.0)
Introduced on the Z9100–ON.
9.8(0.0P5)
Introduced on the S4048-ON.
9.8(0.0P2)
Introduced on the S3048-ON.
9.7(0.0)
Introduced on the S6000–ON.
9.2(1.0)
Introduced on the Z9500.
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 filter route information. In particular, the use of regular expressions to filter routes based on AS-PATHs and communities is 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 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
DellEMC(conf-router_bgp)# no bgp regex-eval-optz-disable
DellEMC(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

DellEMC(conf-router_bgp)#
Related Commands
  • show ip protocols — view information on all routing protocols enabled and active on the E-Series.

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