What happens to multicast traffic when IGMP snooping is enabled?

When IGMP snooping is enabled on a switch, it optimizes the management of multicast traffic by allowing the switch to listen in on the Internet Group Management Protocol (IGMP) messages between hosts and routers. This process helps the switch to learn which devices are interested in receiving multicast traffic and only forwards this traffic to those specific ports, rather than broadcasting it to all ports.

As a result, while the switch's CPU might not slow down the traffic directly, enabling IGMP snooping can lead to more efficient traffic management. The switch will not forward multicast packets to all ports but will instead send them only to the ports with active subscribers. This reduces unnecessary load on the switch’s CPU and network bandwidth, leading to improved overall performance. However, a poorly configured switch or an overload of multicast traffic may still impact performance indirectly.

Therefore, while the statement about the CPU slowing down the traffic may not be strictly accurate in the context of normal switch operations and efficient multicast management, it indicates an understanding that IGMP snooping minimizes unnecessary multicast traffic that could burden the CPU. This highlights the importance of efficient traffic management in avoiding potential performance issues related to broadcast and multicast traffic.