Friday, 22 December 2017

[Workaround and Fix] - Power given, but Power Controller does not report Power Good - Cisco 2960X Stack

If you hit this page, I think you have encountered an issue similar to what I have faced in my production environment yesterday. But still let me give you a brief about what I had seen so that you can compare it with your problem and apply the fix if needed.


Couple of PCs which were connected to our access layer switch WS-C2960X-48LPS-L were continuously flapping. It was not the link flap, but a POE related flap. Look at the strange alerts on the interfaces,

%ILPOWER-3-CONTROLLER_PORT_ERR: Controller port error, Interface Gi1/0/32: Power given, but Power Controller does not report Power Good
%ILPOWER-7-DETECT: Interface Gi1/0/32: Power Device detected: IEEE PD
%ILPOWER-5-POWER_GRANTED: Interface Gi1/0/32: Power granted
%ILPOWER-5-IEEE_DISCONNECT: Interface Gi1/0/32: PD removed
%ILPOWER-7-DETECT: Interface Gi1/0/32: Power Device detected: IEEE PD


This just kept happening again and again. Though the device doesn't need POE, it appeared to be related to POE negotiation. So as a workaround I just disabled POE on the interface using below command after which the alerts just disappeared.

Switch(config-if)int g1/0/32
Switch(config-if)#power inline never
And when we checked with Cisco for the solution, they said it is a hardware fault and raised RMA for the device. 

I hope this piece of information was useful for you.

GNS3 and Palo Alto Integration - Required download links

Last week I tried to setup Palo Alto in Vmware workstation and link it with GNS3 software. In that process, I found below download links to be useful and I wanted to share it with you all.

GNS3 Palo Alto Support Page

Here is the PA GNS3 appliance support page:-

Palo Alto Vmware Download Images







Leave a comment if you think this is useful and let me know if you are looking for any other such links. 

Wednesday, 4 January 2017

CCNA Wirelss Notes - Part 1 - Understanding basic wireless theory

In order to understand the CCNA wireless topics it's very essential to go through the following basic wireless physics concepts terms. So I have just added the notes and an image for every term to help to understand the topics better.


The number of times the signal makes one complete up and down cycle in 1 second.

Frequency is related to bandwidth as it tells how many cycles per second.


The wavelength is a measure of the physical distance that a wave travels over one complete cycle. Wavelength is usually designated by the Greek symbol lambda (λ). The wavelength decreases as the frequency increases.