https://songkou.github.io/tags/multicast/Recent content in Multicast on Council of ElrondHugoenTue, 21 Jul 2026 00:30:00 +0800https://songkou.github.io/posts/arista-vxlan-bum-her-vs-multicast/Tue, 21 Jul 2026 00:30:00 +0800https://songkou.github.io/posts/arista-vxlan-bum-her-vs-multicast/<p>A VXLAN fabric has to answer one question before any host can talk: <strong>how does BUM traffic (Broadcast, Unknown unicast, Multicast) reach every remote VTEP?</strong> There are only two data-plane answers — head-end replication (HER, also called ingress replication) or an IP multicast underlay — and two control-plane ways to drive each of them (static configuration or BGP EVPN).</p> <p>This lab builds the same Arista fabric four times, once per combination:</p>