Allied Telesis AT-S62 - Manual (Page 612)

Chapter 35: Port Parameters
Section VIII: Web Browser Management 612
You should note the following concerning the operation of Auto-
Negotiation on the switch port:
❑ In order for a switch port to successfully Auto-Negotiate 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 will default to half-duplex if it
detects that the end-node is not using Auto-Negotiation. This will
result in a mismatch if the end-node is operating at a fixed duplex
mode of full-duplex.
To avoid this problem, when connecting an end-node with a fixed
duplex mode of full-duplex to a switch port, you should disable
Auto-Negotiation on the port and set the port’s speed and duplex
mode manually.
❑ If you disable Auto-Negotiation on a 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.
Auto-Negotiate: The port will Auto-Negotiate both speed and
duplex mode. This is the default.
❑ 10Mbps - Half Duplex
❑ 10Mbps - Full Duplex
❑ 100Mbps - Half Duplex
❑ 100Mbps - Full Duplex
HOL Blocking
For a definition of Head of Line Blocking, refer to page 102.
This parameter can prevent Head of Line Blocking from occurring
on a port. The parameter sets a threshold on the utilization of a
port’s egress queue. When the threshold for a port is exceeded,
the switch signals other ports to discard packets to the
oversubscribed port. The number for this value represents cells. A
cell is 64 bytes. The range is 1 to 61,440 cells. The default is 7,168.
Status
You use this selection to enable or disable a port. When disabled,
a port will not accept or forward frames.
You might want to disable a port and prevent packets from being
forwarded if a problem occurs with the node or cable connected
to the port. Once the problem has been fixed, you can enable the
port again to resume normal operation.