Forum Discussion

Ron_Peters_2122's avatar
Ron_Peters_2122
Icon for Altostratus rankAltostratus
Sep 15, 2016

ARP/MAC Tables Not Updating on Core Switches After F5 LTM Failover (GARP Issue?)

We have two F5 LTM 5250v appliances configured with 2 vCMP instances each in an HA pair (Active/Standby). Each F5 5250v has a 10G uplink to two core switches (Cisco Nexus 7010) configured as an LACP ...
application delivery
arp
fail over
gratuitous arp
LTM
tatmotiv's avatar
tatmotiv
Icon for Cirrostratus rankCirrostratus
Sep 21, 2016

Can you really be sure that there is no packet loss in the N7Ks? We have experienced a similar situation and it turned out that the N7Ks indeed dropped packets, but those could not be seen in any counters. It took quite some effort with sniffers and taps to prove this.

 

However, as a workaround you should consider enabling MAC masquerading in the according traffic-group(s) of the BigIP. Thus, there is no longer need for sending grat ARPs in case of failover.