Enterasys SmartSwitch 6000, User Manual

Page: 57 / 231

The Device View
2-38 Managing the Module
Use the options in this window to select the desired mode:
Standard Mode
In Standard Mode, an interface can only either transmit or receive at any given time, and
must wait for one activity to be completed before switching to the next activity (receive or
transmit). In this mode, standard wire speeds (10 Mbps for Ethernet, 100 Mbps for FDDI)
are available.
Full Duplex
In Full Duplex Mode, an interface can both receive and transmit packets at the same time,
effectively doubling the available wire speed to 20 Mbps (for Ethernet) or 200 Mbps (for
FDDI).
Be sure to click on the Apply button to set your changes; note that the interface’s current
mode can be determined by the field selected in the window.
TIP
If you select the Configuration option available for a Fast Ethernet interface, an entirely
different window will appear; see
Configuring Fast Ethernet Ports on First Generation
Modules , on page 2-39 , or Configuring Ethernet Ports on Second Generation Modules ,
page 2-44 , for information on configuring these ports.
WARNING
For standard Ethernet interfaces, 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.
Similarly, an FDDI Full Duplex connection must also only be run point-to-point between
two supporting FDDI interfaces (e.g., another HSIM-F6), since the dual bandwidth is
attained by running data on both primary and secondary paths simultaneously. Since Full
Duplex overrides standard FDDI protocol (and eliminates ring redundancy), it will not
operate in a “ring” configuration, but only as a point-to-point high speed data trunk
between hubs. Note that you must use Local Management to configure your HSIM-F6 for
Full Duplex operation prior to making physical connections. Refer to your Local
Management Guide for more information.