Latency increases as a function of frame length.įragment-free (modified cut-through)-The switch reads the first 64 bytes before forwarding the frame. If the CRC is bad, the frame is discarded.
The entire frame is read, and a cyclic redundancy check (CRC) is performed. Store and forward-The switch waits to receive the entire frame before forwarding. There are three primary frame-switching modes:Ĭut-through-The switch checks the destination address and immediately begins forwarding the frame. Loop avoidance-When the switched network has redundant loops, the switch can prevent duplicate frames from traveling over multiple paths.
If the address is known, the frame is sent only on that port if the address is unknown, the frame is flooded to all ports except the one from which it originated. The addresses are stored in a bridge forwarding database.įorwarding and filtering-Switches determine which port a frame must be sent out to reach its destination. MAC address learning-A Layer 2 switch learns the MAC addresses of devices attached to each of its ports. Layer 2 switches have three main functions:
Basic Layer 2 Switching (Bridging) FunctionsĮthernet switching operates at OSI Layer 2, creating dedicated network segments and interconnecting segments.
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