Speed vs Bandwidth vs Clock Rate commands in CISCO IOS

1. Speed

Applies to ethernet interfaces. It changes the actual physical transmission rate of the port hardware.

R1(config-int)# speed 100 -- Sets the transmission rate to 100 Mbps

Note

Speed works in Mbps

2. Clock Rate

Applies to serial interfaces. Changes the actual physical transmission rate of a serial cable.

R1(config-int)# clock rate 6400 -- Sets the transmission rate to 64 Kbps

Note

Clock rate works in bps

3. Bandwidth

Applies to any interface. This is purely a logical command. It does absolutely nothing to the physical hardware, and it does not change how fast the port actually sends or receives data.

R1(config)# interface serial1/0
R1(config-if)# bandwidth 768 -- Sets que transmission rate to 768 Kbps

Note

Bandwidth works in Kbps