Forum Discussion
AltocumulusFailover Multicast addressing best practice for vCMP
We have multiple vCMP F5 instances using the same default Failover Multicast address and port (224.0.0.245:62960). All vCMP F5 instances use the same vlan for high availability. What is the best practice configuration for failover multicast addressing? Should the addressed be unique if they are all on the same vlan? Should we change the multicast address from the default so each instance uses a unique multicast address/port or leave the defaults and all instance heartbeats point to the same multicast address? I am aware that the multicast is a secondary measure for failover being combined with unicast, however I would like to know what is best practice for the multicast addressing.
2 Replies
er_sandy_27437Nimbostratus
It is advised to have individual self-IPs for each vCMP guest for HA, Sync and Failover configuration. You can refer to following KB article for more clarity on this
https://support.f5.com/csp/article/K15930
Leonardo_SouzaCirrocumulus
Multicast is a destination address. If you want to change, at least the HA pair should be pointing to the same destination.
224.0.0.245 does not look to be a registered, and I guess is just because 245 is a conversation of F5 from hex to decimal (like they do with the default management IP). Here are some reserved IPs:
https://en.wikipedia.org/wiki/Multicast_address
I guess that the receiving devices will differentiate based in the source IP or source MAC, when they receive a packet from the peer device. You can take a tcpdump, use the wireshark plugin (as I think it has HA decoders), and check what happens.
https://devcentral.f5.com/wiki/AdvDesignConfig.F5WiresharkPlugin.ashx
I personally, never configure multicast. An HA vlan and management as unicast, should be more then enough. However, F5 does recommend that per this documentation:
https://support.f5.com/csp/article/K13915multi
