Allied Telesis AT-S63 - Manual (Page 125)

AT-S63 Management Software Menus Interface User’s Guide
Section I: Basic Operations 125
Note
When you set negotiation to Manual, items 7 (Speed), 8 (Duplex),
and 9 (MDI Crossover) are displayed.
If you select Auto for Auto-Negotiation, which is the default setting, the
switch sets speed, duplex mode, and MDI crossover for the port
automatically. The switch determines the highest possible common
speed between the port and its end node and sets the port to that
speed. This helps to ensure that the port and the end node are
operating at the highest possible common speed.
Note the following items concerning the operation of Auto-Negotiation
on a switch port:
ˆ A 10/100/1000Base-T twisted pair port must be set to set to Auto-
Negotiation to operate at 1000 Mbps. You cannot manually
configure a 10/100/1000Base-T twisted pair port to 1000 Mbps.
ˆ In order for a switch port to successfully autonegotiate its duplex
mode with an end node, the end node should also be using Auto-
Negotiation. Otherwise, a duplex mode mismatch can occur. A
switch port using Auto-Negotiation defaults to half-duplex if it
detects that the end node is not using Auto-Negotiation. This can
result in a mismatch if the end node is operating at a fixed duplex
mode of full-duplex.
ˆ To avoid this problem when connecting an end node with a fixed
duplex mode of full-duplex to a switch port, disable Auto-
Negotiation on the port and set the port’s speed and duplex mode
manually.
ˆ When a twisted pair port is set to Auto-Negotiation, the MDI/MDI-X
setting for the port is locked at auto-MDI/MDI-X. The switch
automatically determines the correct MDI/MDI-X setting. You
cannot set MDI/MDI-X manually.
ˆ When Auto-Negotiation is disabled on a twisted pair port, the auto-
MDI/MDI-X feature on a port is also disabled, and the port defaults
to the MDI-X configuration. Consequently, if you disable Auto-
Negotiation and set a port’s speed and duplex mode manually, you
might also need to set the port’s MDI/MDI-X setting as well.
ˆ An SFP or GBIC module uses Auto-Negotiation to set its speed
and duplex mode. If the SFP or GBIC is paired with a twisted pair
port whose speed and duplex mode were set manually, the speed
reverts to Auto-Negotiation when an SFP or GBIC module
establishes a link with an end node. For further information, refer to
“Redundant Twisted Pair Ports” on page 55.