Specifications

9E312/9E423 Module Bridging
3-28 Duplex Modes
Duplex Modes
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.
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.
WARNING
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.