Reference Guide

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.
Z9500
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
9.2(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.
bgp soft-reconfig-backup
To avoid the peer from resending messages, use this command only when route-refresh is not negotiated.
Z9500
Syntax
bgp soft-reconfig-backup
To return to the default setting, use the no bgp soft-reconfig-backup command.
Defaults Off
Command Modes ROUTER BGP
Command
History
This guide is platform-specific. 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.
380 Border Gateway Protocol