Allied Telesis x610 Series Layer 3 - Manual (Page 105)

x610 Series Layer 3 Gigabit Ethernet Switches Installation Guide
105
Twisted Pair Port Link LED is Off
When a twisted pair port on the switch is connected to a properly operating
end node, the Link LED for the port should be on. If a Link LED is off, do
the following:
Note
A 1000Base-T connection can take from five to ten seconds to
establish a link.
ˆ
Verify that the end node connected to the port is powered ON and is
operating properly.
ˆ
Check that the twisted pair cable is securely connected to the port on
the switch and to the port on the end node.
ˆ
Make sure that the twisted pair cable does not exceed 100m (328 ft).
ˆ
Verify that you are using the appropriate category of twisted pair cable.
For information, refer to Table 17 on page 90.
ˆ
Determine if a crossover cable is required. Since the twisted pair ports
feature auto MDI/MDI-X, you should be able to use a straight-through
cable regardless of the type of device you connect to a port. However,
if you disable Auto-Negotiation on a port and set a port’s speed and
duplex mode manually, the port defaults to MDI-X. Disabling Auto-
Negotiation may require manually configuring a port’s MDI/MDI-X
setting or using a crossover cable.
ˆ
Make sure that the operating parameters of a port on the switch are
compatible with the end node to which the port is connected. This may
require using the switch’s operating system software.
ˆ
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 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.
To avoid this problem, disable Auto-Negotiation on a switch port and
set the port’s speed and duplex mode manually if the end node has a
fixed duplex mode of full-duplex.
ˆ
The switch has a bad cable detection feature that enables it to
determine if a twisted pair cable has a electrical short that might cause
a network loop. If the switch detects a bad cable on a port, it does not
establish a link on that port. In this situation, replace the cable.