3Com 3800 - Manual (Page 50)

3-14 C HAPTER 3: A CCESSING T HE S WITCH
Configuring
Autonegotiation
By default, the Switch 3800 is configured to use autonegotiation for all
ports. Autonegotiation on 10/100 Mbps ports is used to automatically
determine speed and duplex settings. You can select to manually
configure the duplex and speed settings of 10/100 Mbps ports. Manual
configuration would be used when the remote device does not support
autonegotiation or when an interoperability issue exists.
The Switch 3800 Gigabit Ethernet port only supports a speed of 1,000
Mbps and full duplex. Even though these parameters are fixed,
autonegotiation on Gigabit links still allows proper link initialization and
should be used whenever possible. Manual configuration would be
used when the remote device does not support autonegotiation or
when an interoperability issue exists.
10/100 port settings Fast Ethernet ports can connect to either 10BASE-T or 100BASE-TX
networks. By default, the ports autonegotiate port speed and duplex
settings. You can manually determine these settings by turning
autonegotiation off and providing speed and duplex settings. To
configure port speed and duplex settings on 10/100 Mbps ports, use
the following command:
config port <portlist> auto off (speed [10 | 100]} duplex
[half | full]
To restore autonegotiation, use the following command:
config port <portlist> auto on
Gigabit port settings By default the Gigabit port on the Switch 3800 uses autonegotiation to
establish proper link initialization. Speed and duplex settings cannot be
modified. To turn off autonegotiation, use the following command:
config port <portlist> auto off duplex full
The duplex setting must be provided even though the duplex setting
may not be modified. To restore autonegotiation, use the following
command:
config port <portlist> auto on
SW3800.BK Page 14 Tuesday, May 5, 1998 5:20 PM