Users Guide

BGP Regular Expression Optimization
Dell Networking OS optimizes processing time when using regular expressions by caching and re-using regular expression evaluated
results, at the expense of some memory in RP1 processor.
BGP policies that contain regular expressions to match against as-paths and communities might take a lot of CPU processing time, thus
affect BGP routing convergence. Also, show bgp commands that get filtered through regular expressions can to take a lot of CPU
cycles, especially when the database is large.
This feature is turned on by default. If necessary, use the bgp regex-eval-optz-disable command in CONFIGURATION ROUTER
BGP mode to disable it.
Debugging BGP
To enable BGP debugging, use any of the following commands.
• View all information about BGP, including BGP events, keepalives, notifications, and updates.
EXEC Privilege mode
debug ip bgp [ip-address | peer-group peer-group-name] [in | out]
• View information about BGP route being dampened.
EXEC Privilege mode
debug ip bgp dampening [in | out]
• View information about local BGP state changes and other BGP events.
EXEC Privilege mode
debug ip bgp [ip-address | peer-group peer-group-name] events [in | out]
• View information about BGP KEEPALIVE messages.
EXEC Privilege mode
debug ip bgp [ip-address | peer-group peer-group-name] keepalive [in | out]
• View information about BGP notifications received from or sent to neighbors.
EXEC Privilege mode
debug ip bgp [ip-address | peer-group peer-group-name] notifications [in | out]
• View information about BGP updates and filter by prefix name.
EXEC Privilege mode
debug ip bgp [ip-address | peer-group peer-group-name] updates [in | out] [prefix-list name]
• Enable soft-reconfiguration debug.
EXEC Privilege mode
debug ip bgp {ip-address | peer-group-name} soft-reconfiguration
To enhance debugging of soft reconfig, use the bgp soft-reconfig-backup command only when route-refresh is not
negotiated to avoid the peer from resending messages.
In-BGP is shown using the show ip protocols command.
Dell Networking OS displays debug messages on the console. To view which debugging commands are enabled, use the show
debugging command in EXEC Privilege mode.
To disable a specific debug command, use the keyword no then the debug command. For example, to disable debugging of BGP
updates, use no debug ip bgp updates command.
To disable all BGP debugging, use the no debug ip bgp command.
To disable all debugging, use the undebug all command.
Storing Last and Bad PDUs
Dell Networking OS stores the last notification sent/received and the last bad protocol data unit (PDU) received on a per peer basis. The
last bad PDU is the one that causes a notification to be issued.
In the following example, the last seven lines shown in bold are the last PDUs.
Border Gateway Protocol IPv4 (BGPv4)
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