arp request broadcast storm

[Simon Merckx]

At regular intervals a see many broadcasts on our network.
I did a capture. I saw that they where arp requests from our router(5308XL).

When I do a ping from the router to a ip-adres that's not in the arp-table, the same thing happens.

Is there a known problem with the arp table in a 5308Xl. I have firmware 9.03

I read the release noets from that version up until the latest. I don't see any problem that looks like mine.

I can do a firmware upgrade. But I have to be sure that it will fix te problem.

Shutting down our network is not easy.

[Mohieddin Kharnoub]

Hi

This can be caused usually if you have a Spanning Tree topology changes, that makes your Routing switch 5300 flush the MAC table to build it from scratch.

Check if you have any loops in your network, and check that your 5300 has the best ROOT priority, so no other device can preempt the spanning tree Root.

Usually, most of the traffic on the Core is ARP requests, and thats why Vlans is considered on of the best practices for Network Optimizations especially if you have more than 100 end device in one flat network.

Upgrading the firmware is very Beneficial, especially in your case where the 5300 does Routing, so i thin it worth it to bring the network down for 5 minutes for that purpose.

Good Luck !!!

[Simon Merckx]

Thanks for the quick answer.

When I do a show span, there aren't any recent topology changes.

The network still works during a broadcast storm. During a storm the router sends many arp requests(500 to 700 broadcasts per second). Every request during the storm is for the same ip-adres. This adres changes with every storm.

My experience with loops teaches me that they almost bring the whole network down.
Spanning tree is configured in normal mode on every interface on the router. This should prevent loops.

The router is also de root switch for STP.

The arp table isn't flushed during a broadcast storm. When I do a "show arp" the current entries are still there before, during and after the storm.

I will try a firmware upgrade.

Thanks for your advice.

[Simon Merckx]

The problem disappeared last week.
When a company took away their demo equiment.

It was wireless equipment. Maybe something wrong in the config.

[Simon Merckx]

The problem disappeared last week.
When a company took away their demo equiment.

It was wireless equipment. Maybe something wrong in the config.