Tips and Tricks

From CiscoClue

This section covers Tips and Tricks for Cisco routers. General tips & tricks will be listed here as well as platform specific options.

Contents

Protocols

  • HSRP - Host Standby Router Protocol


Diagnostics Tools

Cisco TDR (Time Domain Reflectometer) - Integrated cable tester

GSR Convergence Improvements

process-max-time 50

This will lower the maximum time allocated for a process to run to 50ms rather than the default of 200ms.

ip routing protocol purge interface

This will allow an interface link state change to directly impact the RIB rather than waiting on routing protocol updates to the RIB to take place.

ip cef table loadinfo force

This will allow common prefixes on a LC-FIB to be associated with a pointer that permits rapid modification when the LC-FIB needs to be updated. This can save several seconds in convergence events on a network. Use caution with this command on E4/E4+ linecards as this increases LC memory usage.

 service internal

 ip cef linecard ipc service-timer 50

This will lower the timer (200ms default) used for transmitting XDR (essentially CEF writes) messages to a linecard.

Hidden Commands

There are many hidden commands. The hidden command

show parser dump

will allow you to reveal them by dumping the parser data (the unrolled parse tree) ,

show parser dump exec
and
show parser dump config
are the best way of doing this, along with
show parser dump exec debug
which will write a file to your disk.

How to recover stuck telnet/ssh sessions

How to recover stuck telnet/ssh sessions