Giuseppe Larosa Mon, 07/14/2008 - 12:08

Hello Greg,

we use 1% on gigabit ethernet ports.

You can see your baseline using the output of show interface.

You just need to provide enough BW for the ARP process to be successful, and for DHCP requests in modern networks routing protocols use multicast destination addresses both at L3 and at L2.

Some forms of Windows networking like NetBIOS over TCP can use broadcasts take care if you don't use WINS server in your network.

We see broadcast storm control in action during loops and after that the dropped frames result as output drops.

Hope to help

Giuseppe Tue, 07/15/2008 - 05:24

Thank you for the info Giuseppe. Question about the Gig Ether port configs. We are configuring this on user ports in an office, sometimes these ports auto negotiate to a lower speed such as 100Mbit. I'm guessing a 1% threshold value might interfere with normal operation at this point. Can you provide some insight?



Giuseppe Larosa Tue, 07/15/2008 - 09:32

Hello Greg,

check your cabling if you want that all ports go at 1000 Mbps.

Or you can consider to set the port speed at 100 Mpbs full but this can impact end user devices.

You could review the storm-control using the sh intefaces : 1% for 1Gbps, 10% for 100 Mbps ports.

In this way you provide up to 10 Mbps to broadcast traffic

Hope to help



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