How much performance will be lost if RMON is activated in promiscuous mode?

[josevnz]

Greetings,

I saw the following article about RMON on the Cisco 2900XL and 3500XL:

<A HREF="javascript:newWin('http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/fun_c/fcprt3/fcmonitr.htm#19432')">http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/fun_c/fcprt3/fcmonitr.htm#19432</a>

Looks like the promisc mode will provide more data back but the performance hit will be significative. We want to monitor bandwidth usage among others stats but is critical to use than the network is performing a peak performance.

Has anyone in this forum played with this? If so, what are the recomendations?

JV.

[rmushtaq]

See if http://www.cisco.com/warp/public/126/perfmgmt.htm is of some help here.

[josevnz]

Thanks for your answer. I found another article that show how to check the CPU usage on my Cisco Switch (i don't have the url at hand but i found it on this forums).

Saddly our cisco equipment software doesn't have the full RMON support enabled (only traps and informs) so i will have to resour to other techniques (or upgrade it) to get my stats.

Thanks.