Silent Hosts in EVPN Fabrics
The Dynamic MAC Learning versus EVPN blog post triggered tons of interesting responses describing edge cases and vendor bugs implementation details, including an age-old case of silent hosts described by Nitzan:
Few years ago in EVPN network, I saw drops on the multicast queue (ingress replication goes to that queue). After analyzing it we found that the root cause is vMotion (the hosts in that VLAN are silent) which starts at a very high rate before the source leaf learns the destination MAC.
It turns out that the behavior they experienced was caused by a particularly slow EVPN implementation, so it’s not exactly the case of silent hosts, but let’s dig deeper into what could happen when you do have silent hosts attached to an EVPN fabric.