Lessons · Network switches · why a switch gets replaced
The one thing that has to exist before the box comes out
A configuration backup, taken off the switch and read, is the only part of a swap that cannot be improvised on the night.
Hone is a place to practise programming. This is one of its lessons, written out in full and free to read without an account.
What it is for
Everything else about a replacement can be worked out while you stand there. The configuration cannot: the moment the old box is unplugged, the only copy of what it was doing is whatever you took beforehand.
How to think about it
Console in, look at what is there, save it, send it somewhere else, then open the file. Five minutes, and it is the five minutes the rest of the night rests on.
Worked example
enableThe # prompt. Everything worth doing needs it.
show versionWhat software this box runs. The replacement should not be older.
show running-configWhat it is doing. Read it before you decide the swap is simple.
copy running-config startup-configSaved on the box, which protects against a reboot and nothing else.
copy running-config tftp://10.0.0.9/idf3.cfgOff the box. This one is the backup.
Your turn
Send this switch's live configuration to the server as idf3.cfg.
running-config startup-config
Console into a switch
The trap
Saving to startup-config and calling it a backup. It is on the same box that is about to be unracked.