What Does an Ethernet Bridge Do with Multicast Frames?

AC

An Ethernet bridge is a device that connects multiple network segments or LANs (Local Area Networks) together to form a larger network. It operates at the Data Link Layer (Layer 2) of the OSI (Open Systems Interconnection) model and can filter and forward Ethernet frames based on their MAC addresses.

When all interfaces of an Ethernet bridge are in a single broadcast domain, it means that any broadcast or multicast frame sent on one interface will be forwarded to all other interfaces. In this case, the bridge does not have to perform any special tasks to forward multicast frames.

However, if the bridge is configured to use a separate broadcast domain for each interface, it must perform additional tasks to forward multicast frames.

The two tasks that the bridge performs in response to receiving a multicast frame are as follows:

1. It learns the source MAC address: When a multicast frame is received on an interface, the bridge learns the source MAC address of the device that sent the frame. This information is stored in the bridge's MAC address table, which is used to filter and forward frames based on their MAC addresses.

2. It floods the frame out of particular interfaces based on its multicast MAC table: The bridge then checks its multicast MAC table to determine which interfaces should receive the multicast frame. The multicast MAC table contains entries that associate multicast MAC addresses with specific interfaces. If an entry exists for the multicast MAC address of the received frame, the bridge forwards the frame only to the interfaces listed in the entry. If no entry exists for the multicast MAC address, the bridge floods the frame out of all interfaces except the one on which it was received.

Therefore, the correct answers to the question are A. It learns the source MAC address and D. It floods the frame out of particular interfaces based on its multicast MAC table.