[ixpmanager] What MAC address-table aging-time are you using?

[Nick Hilliard]

Salvador Bertenbreiter via ixpmanager wrote on 25/04/2026 04:18:
> We are suffering from some unknown unicast cases. I checked that we are 
> currently using 300 seconds of aging-time in our switches, and according 
> to my research, this could be a cause of the unknown unicast issue.

If the mac aging time on the switch infrastructure is less than the arp 
timer on the routers, then you'll see UU frames.

Some vendor defaults for ARP timeout:

Juniper: 20 minutes
Cisco XR and XE: 4 hours
Mikrotik: 30 seconds

The easiest way to work around this is to increase the mac aging time. 
The arguably better way to fix it is to use programmed MAC addresses on 
each port with arp / nd proxy, and not depend on mac discovery at all.

Nick