Tag Archives: IOS Feature

Perpetual and Fast PoE are friends, m’kay?

PoE icon was borrowed from LightwareHave you ever heard about two new PoE enhancements that are available on some Catalyst 3850 and all Catalyst 9K platforms? If not, you’re not alone. I only found out about these few months back by accident when I was troubleshooting some issues. There are two great features available for you to configure on PoE-enabled switches:

  • Perpetual PoE: preserves power during warm reload
  • Fast PoE: provides power to the port after cold start at pre-outage levels

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Cisco IOS archive feature path variables

There’s something you might like.

Cisco IOS archive feature supports two variables that can be used to define path property. Those are $t for date/time and $h for hostname. Date/time format can be adjusted with service timestamps log command. Also, don’t forget to configure an appropriate timezone name and offset. Here’s an example.

service timestamps log datetime localtime show-timezone year
clock timezone EET 2
clock summer-time EEST recurring last Sun Mar 3:00 last Sun Oct 4:00
 log config
  logging enable
 path tftp://$h-$t

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Warning – MODE button!

You all know that fancy Mode button located on every single non-modular Catalyst switch (Cisco 3750/3560). It gives you a way to visualize switchports information – like duplex mode, speed, stack member, master switch, PoE status and so on. This magic button also provides you with the only available method to enter a recovery mode (if enable password had been lost). All these features are well known to any Cisco engineer – this is the basis of CCNA course that relates to L2/switches subject. Now, imagine another not-so-well-known feature which can put you in the middle of the nightmare… Continue reading