A customer recently implemented WLC wireless multicast. Clients and connecting at the highest mandatory wireless rate of 24 Mbps and are receiving multicast traffic, but WLC cpu utilization and…

Global Multicast mode must be verified as enabled on the WLC because it is the foundational setting that allows the controller to handle multicast traffic natively rather than falling back to inefficient per-client replication.

IGMP snooping on the WLC should be disabled because access points already perform this function at the radio level; running it on the controller as well duplicates processing and contributes directly to the elevated CPU utilization observed.

Raising the mandatory rate to 54 Mbps changes the radio transmission rate for multicast frames but does not reduce WLC CPU utilization or wired network load, which are caused by unicast replication mode, not the data rate.

MLD snooping is the IPv6 equivalent of IGMP snooping and applies to IPv6 multicast groups; this IPv4 multicast scenario is governed by IGMP, so enabling MLD v1 snooping does not address the described problem.

Multicast-Unicast mode causes the WLC to clone each multicast frame into an individual unicast copy for every subscribed wireless client, which is the primary cause of both high CPU utilization and increased wired-side traffic; switching to Multicast-Multicast mode and assigning a multicast group address allows a single multicast stream to be used across the network, resolving both symptoms.

Configuring PIM sparse-dense-mode on wired L3 VLAN interfaces addresses upstream IP multicast routing, not the WLC-level replication behavior that is causing the elevated CPU and bandwidth load.