In a VLAN Switching system, the A/V signal is switchport-based. This means that all Receivers connected to the same switch port will always show the same Transmitter. It also means that a port only has the bandwidth of a single A/V signal so the full 1Gbps of the network wire is available to it. No bandwidth management is needed.
Example: 4 Receivers - 3x 509POE and 1x 508POE - are connected to the same network port. Since they all watch the same video signal, they can be setup to show a 2x2 video wall. Only a single port needs to be switched for the entire wall to show a different source.
In a Multicast Switching system, the A/V signal is Receiver-based. This means that each Receiver connected to the same switch port can potentially show different A/V signals. The 1Gbps of the network wire must be split between the different A/V signals, reducing the bandwidth available to each signal. A single Transmitter outputs between 250 - 850 Mbps, with 400 - 500Mbps being the average usage. If Receivers on the same port are watching more than 2 different Transmitters, bandwidth management is needed.
Example: 4 Receivers - 3x 509POE and 1x 508POE - are connected to the same network port. The Receivers are independent and can watch any sources. The Transmitters have had their bandwidth limited to 200Mbps to allow for up to 4 unique, simultaneous signals.