As we know, in a multicast Layer 2 network, customers often face insufficient bandwidth.
So we can configure the Layer 2 multicast CAC to solve it.
Layer 2 multicast Call Admission Control (CAC) limits the number of all multicast groups or the number of multicast groups in a channel by controlling learning of Layer 2 multicast forwarding entries.
Layer 2 multicast CAC can be deployed on VLANs or virtual private LAN service (VPLS) networks running Internet Group Management Protocol (IGMP) snooping.With Layer 2 multicast CAC configured, a switch will not generate Layer 2 multicast forwarding entries for new requests after the number of groups reaches the configured limit.