Difference between revisions of "LAN Switches"
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(Created page with "Switching: *'''Store-and-forward switching''' - switch receives the entire frame, and computes CRC. IF CRC is valid, the switch looks up the destination address which determin...") |
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Switching: | Switching also know as frame forwarding methods: | ||
*'''Store-and-forward switching''' - switch receives the entire frame, and computes CRC. IF CRC is valid, the switch looks up the destination address which determines the outgoing interface. The frame is then forwarded | *'''Store-and-forward switching''' - switch receives the entire frame, and computes CRC. IF CRC is valid, the switch looks up the destination address which determines the outgoing interface. The frame is then forwarded | ||
*'''Cut-through switching''' - switch forwards the frame before it is entirely received. At the minimum the destination address of the frame must be read before the frame can be forwarded | *'''Cut-through switching''' - switch forwards the frame before it is entirely received. At the minimum the destination address of the frame must be read before the frame can be forwarded | ||
Revision as of 19:18, 24 October 2014
Switching also know as frame forwarding methods:
- Store-and-forward switching - switch receives the entire frame, and computes CRC. IF CRC is valid, the switch looks up the destination address which determines the outgoing interface. The frame is then forwarded
- Cut-through switching - switch forwards the frame before it is entirely received. At the minimum the destination address of the frame must be read before the frame can be forwarded
- Fast-forward switching - immediately forwards a packet after reading the destination address. Latency is measured from the first bit received to the first bit transmitted
- Fragment-free switching - the switch stores the first 64 bytes of the frame before forwarding, the reason to read the first 64 bytes is most network errors and collisions occur during the first 64 bytes
Some switches are configured to perform cut-through switching on a per-port basis until a user-defined error threshold is reached and then they automatically change to store-and-forward. When the error rate falls below the threshold, the port automatically changes back to cut-through switching.