User's Manual
AT-9000 Gigabit Ethernet Switch Installation Guide
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The default speed setting for the ports is Autonegotiation. This
setting is appropriate for ports connected to host devices that also
support Autonegotiation.
The default speed setting of Autonegotiation is not appropriate for
ports connected to 10/100Base-TX host devices that do not
support Autonegotiation and have fixed speeds. For those switch
ports, you should disable Autonegotiation and set the port’s speed
manually to match the speeds of the host devices.
The 10/100/1000Base-T ports must be set to Autonegotiation, the
default setting, to operate at 1000Mbps.
The default duplex mode setting for the ports is Autonegotiation.
This setting is appropriate for ports connected to host devices that
also support Autonegotiation for duplex modes.
The default duplex mode setting of Autonegotiation is not
appropriate for ports connected to host devices that do not support
Autonegotiation and have a fixed duplex mode. You should disable
Autonegotiation on those ports and set their duplex modes
manually to avoid the possibility of duplex mode mismatches. A
switch port using Autonegotiation defaults to half-duplex if it
detects that the end node is not using Autonegotiation, which can
result in a mismatch if the end node is operating at a fixed duplex
mode of full-duplex.
If the switch will have a static or an LACP port trunk, create the
trunk first using the switch’s management software before
connecting the cables of the trunk. Otherwise, a network loop will
result, which can adversely affect network performance.
If your network topology contains a loop in which two or more host
devices can communicate with each other over more than one
network path, do not connect the network cables forming the loop
until after you have activated a spanning tree protocol on the
switch. Data loops can adversely affect network performance. For
background information on the different types of spanning tree
protocols supported by the switch, refer to the AT-9000 Series Web
User Guide.