Multicast Snooping Overview

Generally, multicast snooping is a way for a Layer 2 device to “snoop” at the Layer 3 packet content to determine which actions are to be taken to process or forward a frame. There are specific forms of snooping, such as IGMP snooping or PIM snooping. In all cases, snooping involves a device configured to function at Layer 2 having access to Layer 3 (packet) information. Snooping makes multicasting more efficient in these devices.