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Possible arp issue


We have a hub and spoke network with a 6807 Core and 2960X Access switches.  AT several of our location we have radio links with IP addressable industrial equipment hanging off the far end of the radio link.  Our issue is that we just updated the network adapeters on these pieces of industrial equipment but at two sites the host goes down and the only way to bring it back up is clear the arp cache on our Core.  It comes back up for awhile but then goes back down again.  When it goes back down the radio link remains up so it does not appear to be the problem.  Any suggestions?

6 Replies 6

Georg Pauwen
VIP Master VIP Master
VIP Master



what if you configure static MAC addresses for the industrial equipment (example below) ?


2960X(config)#mac address-table static 001c.e26b.13d2 vlan 2 interface GigabitEthernet 0/1

I don't think that would work because the access switch is actually only seeing the macs of the two radios as it is now.  We have a power injector at the far end of the radio link that the host plugs into.



what physical devices (brand/model) does the radio link consist of ?

They are Ligowave LigoDLB 5-15ac radios.  They were working fine with the old network cards in our equipment and they don't go down when the host goes down.  We have another site that is using Engenuis radios that is having the exact same problem but we're only troubleshooting the Ligowave site right now.


paul driver
VIP Expert VIP Expert
VIP Expert

Do you have any port-security apllied to the access-ports?, if you dont already enable spanning-portfast, make sure the ports are actually in an adminstrative mode of access.


default int x/x
int x/x
switchport host
switchport access vlan x

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Kind Regards

I assigned the mac of the host as a static mac on the switchport but that did not work either.   The mac keeps disappearing from the mac table on the switch and then I have to clear the arp cache to get it to come back.  

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