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Do switches flood?
Flooding. Flooding means that the switch sends the incoming frame to all occupied and active ports (except for the one from which it was received). In essence, flooding is when a switch pretends to be a hub. There are two basic reasons why a switch will flood a frame.
Why a switch will always flood a broadcast frame?
Since both the multicast and broadcast addresses are never used in the source address field of a frame, a switch never learns these addresses. And since a switch never learns these addresses, it always floods the frames which have these addresses as the destination address.
Does a switch flood ports if it does not know where to send a packet?
A Layer 2 switch learns most of its information about the location of other endpoints via “listening” to ingressing frames, and when it is not aware of the location, it uses flooding and will learn from the answer.
Why does a switch flood?
The process occurs when a device is initially connected to a network, is moved from one port to another or after 5 minutes of inactivity when the device is typically purged from the forwarding table. A switch that has no room left in its address cache will flood the frame out to all ports.
Which type of traffic is not flooded by a switch?
To prevent flooding unknown-unicast traffic across the switch, it is possible to configure the network equipment to divert unknown-unicast traffic to specific trunk interfaces in order to split broadcast coming from different VLANs or to use specific trunk interfaces for multiple VLANs.
Does each port on a switch have a MAC address?
Like all Ethernet interfaces, every port on a switch has a unique factory-assigned MAC address. As each frame is received on each port, the switching software looks at the source address of the frame and adds that source address to a table of addresses that the switch maintains.