9E312/9E423 Module Bridging

Duplex Modes

WARNING

The Ethernet switch interfaces on a 9E312/9E423 Module will support Full Duplex Switched Ethernet (FDSE) mode. Enabling Full Duplex mode on an interface allows the interface to receive and transmit packets at the same time. On an Ethernet connection that is not using full duplex mode, the interface can transmit or receive packets. The interface has to wait for one activity to be completed before switching to the next activity (receive or transmit). Using the full duplex mode allows for faster transmission for Ethernet connections.

Full Duplex should only be enabled on an interface that has a connection to a single destination address at the other end of the connection (i.e., it is not a segment with an attached repeater cascading the connection to multiple destination addresses).

Full Duplex mode disables the collision detection circuitry at the interface, so that both Transmit and Receive wires can be used simultaneously. With a single destination address at the other end of the connection (for example, if the connection was to a full duplex interface on another switching module, or if a single file server was connected to the full duplex switch port), this essentially doubles the available bandwidth from 10 Mbit/sec to 20 Mbit/sec. Note that the interface at the other end of the connection must also have Full Duplex enabled at the attached interface.

Full Duplex mode must be disabled if the interface is communicating with multiple destinations simultaneously (i.e., if a repeater is cascaded from the interface), since Ethernet relies on Collision Sense for proper operation.

The Duplex Modes Window

The Duplex Modes window allows you to enable/disable (turn on/off) Full Duplex mode capability for each bridging interface on your device. The window lists each interface on the device and whether Full Duplex is “ON” or “OFF.”

To access the Duplex Modes Window from the Bridge Status window:

1.Click on . A pull-down menu will appear.

2.Click on Duplex Mode.... The 9E312/9E423 Module Duplex Modes window, Figure 3-9, will appear.

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Duplex Modes

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Cabletron Systems 9E312, 9E423 manual Duplex Modes Window