How a switch signals an end node to stop transmitting data differs depending on the speed of the end node and switch port. Ports operating at 10 Mbps use flow control while ports operating at 100 Mbps use backpressure.
For a 10 Mbps port, the switch will stop an end node from transmitting data by forcing a collision. A collision on an Ethernet network occurs when two nodes attempt to transmit data using the same data link at the same time. A collision causes end nodes to stop sending data. When the switch needs to stop a 10 Mbps end node from transmitting data, it forces a collision on the data link, which stops the end node. Once the switch is ready to receive data again, the switch stops forcing collisions.
A port running at 100 Mbps uses PAUSE frames, as specified in the IEEE 802.3x standard. Whenever the switch wants an end node running at 100 Mbps to stop transmitting data, it issues a PAUSE frame. The frame simply instructs the end node to cease transmission. The switch continues to issue PAUSE frames until it is ready to again receive data from the end node.
Duplex Mode
Duplex mode refers to the manner in which an end node handles the receiving and transmitting of data. If an end node can receive or transmit data, but not both at the same time, the end node is operating in what is referred to as half- duplex mode. If an end node can both receive and transmit data simultaneously, the node is operating in
Each port on an
The duplex mode for the fiber optic port(s) must be set manually using the 100FX DUPLEX switch on the front panel of the switch. For the fiber optic port to function correctly, this switch must be set to correspond to the duplex mode capability of the end node connected to port.
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