Console or AUX Utilizes High CPU.

[mmali]

Is it true that Console and AUX will utilize more cpu .

Regards

Mudassir.

[ahojmark]

Console logging is high priority in a Cisco router, and the port is slow. So logging to the console can cause slow performance for the whole box.

I always turn off console logging (no logg cons), when the equipment is installed (and further management will be through the VTYs anyway).

-A

[mmali]

You are right,

but is there any Cisco Document about this issue.

Regards

Mudassir.

[a.manosca]

Hi, I don't think there's a specific Cisco docu but you may want to see the following:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_tech_note09186a00800a70f2.shtml#high_cpu

"High CPU Utilization due to Interrupts

CPU interrupts are primarily caused by fast switching of traffic. Interrupts are also generated any time a character is output from the console or auxiliary ports of a router. However, Universal Asynchronous Receiver/Transmitters (UARTs) are slow, compared to the processing speed of the router, so it's not likely that console or auxiliary interrupts can cause a high CPU utilization on the router."

HTH.

[2smith]

Have a look at this document http://www.cisco.com/warp/public/793/access_dial/debug.pdf

Here is a small sample:-

Console Port

Warning: Excessive debugs to the console port of a router can cause it to hang. This is because the

router automatically prioritizes console output ahead of other router functions. Hence if the router is

processing a large debug output to the console port, it may hang. Hence, if the debug output is excessive use

the vty (telnet) ports or the log buffers to obtain your debugs. More information is provided below.