F5 Gratuitous-ARP issue when failover
Hi Last night we upgrade F5 v. 11.5.4 to v.12.1.3 when we failover from old unit v.11.5.4 to newly unit v.12.1.3, We experience some IP has more request timeout than the rest (we ping ip of each vs (~20 ip) when failover) From my understanding, F5 will send G-ARP to neighbour unit when it's active. Is it possible that G-ARP that sent is drop so those IP experience longer downtime due to still using old ARP? or Is it because neighbour unit not use some G-ARP from F5? or Is there any possibilities that make neighbour unit not learn new ARP as expect? Thank you
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 port-channel on the F5 side and a Port-Channel/vPC on the Nexus side. Port-Channel127/vPC127 = F5ADC01 Port-Channel128/vPC128 = F5ADC01 When I look at the MAC address tables on both 7K1 and 7K2, I can see all the individual F5 MACs for each VLAN we have configured on the F5 vCMP instances. We are having an issue during automatic or manual failover where the MAC addresses for the virtual-servers are not being updated. If F5ADC01 is Active and we force it Standby, it immediately changes to Standby and F5ADC02 immediately takes over the Active role. However, the ARP tables on the Nexus 7K Core switches do not get updated so all the virtual-servers continue to have the MAC address associated with F5ADC01. We have multiple partitions on each vCMP instance with several VLANs associated with each partition. Each partition only has a single route-domain the VLANs are allocated to. For traffic to virtual-servers, we are using Auto-MAP to SNAT to the floating Self-IP and using Auto-Last Hop so return traffic passes through the correct source VLAN. We are not using MAC masquerading. The ARP time out on the Nexus 7Ks is 1500 seconds (default) so it takes 25min after a failover for a full network recovery. Eventually the ARP entries age out for all virtual servers and get refreshed with the correct MAC address. Obviously this is not acceptable. I found an SOL article that talks about when GARPs can be missed after failover: SOL7332: Gratuitous ARPs may be lost after a BIG-IP failover event. We have confirmed the upstream core switches are not dropping any GARPs. As a test I went in and manually disabled all virtual-servers and then enabled them and all MACs updated immediately. I have opened a support case with F5 and we have yet to determine where the issue lies. Does anybody have any ideas what the issue might be? If I need to provide more information about our configuration, let me know. We are pretty new to the F5 platform. We recently migrated from the Cisco ACE30 platform. Failover on the ACE platform worked perfectly. Similar cabling setup (two port-channels to two separate Catalyst 6509 switches with an ACE30 module in each switch). After ACE failover, the MAC tables/ARP caches immediately updated. Thank You!