Flooding

Flooding

When a bridge does not have an entry in its bridge table for a specific address, it must transparently pass the traffic through all its ports except the source port. This is known as flooding. The source port is not "flooded" because the original traffic came in on this port and already exists on that segment. Flooding allows the bridge to learn, as well as stay transparent to the rest of the network, because no traffic is lost while the bridge is learning. Figure 1-12 shows how the bridge forwards the traffic on all its ports.