update arp table faster

hardware/software: l3 vlan routing on X670G2 ver15.6.3.2 patch1-8

when MAC/IP address is moved from port to port, sometimes the arp table updates slowly causing connectivity problems with other vlans. L2 connectivity seems fine.

Is there a way to force updates to the arp table immediately when a mac changes in fdb?

Was wondering if configure ip-arp fast-convergence would help.

on force10 I use mac-address-table station-move refresh-arp

anything similar. I'm still pretty new to xos



5 replies

Userlevel 6

The iparp fast-convergence feature maintains the IPARP entry in the event of an FDB flush. So you would essentially see an ARP entry in the table without a port associated until the FDB entry is relearned. It is intended for improved convergence times for ring topologies (EAPS), but could be beneficial in other scenarios as well.
Oh, I see. I don't think it will work for me then, as I don't think it will flush the FDB in the event a station changes port.

Is there a way to trigger the arp table to update ports when a mac is moved from one port to another, or something similar? We currently have ESXi hosts, when we vmotion from one host to another, we lose connectivity to other vlans, for quite a long time. I believe the arp table still has the wrong port associated with the MAC even though it's updated in the fdb
Userlevel 3
Hi Mark, check if your Host can send an GARP via Broadcast, that will Update all dynamic ARP tables on every device in the L2. Or, maybe your HA Solution (?) can use MAC Masquerading (Virtual MAC Address) Best, Jan
Userlevel 6

I believe the fast convergence feature could help in this situation as well, but I would want to setup a lab test just to be sure. To specifically answer your question about other features, there currently is no feature other than the fast convergence feature that I am aware of.
Thanks for the update.

Will run some tests, and post back