Radiance Chassis Stacking Line Card 7
Duplex Switch (FD)
Switch FD determines the duplex mode on all ports that have auto-
negotiation disabled.
• The ports will operate at full duplex if FD is OPEN. (default)
• They will operate at half duplex if FD is CLOSED.
If auto-negotiation is enabled on a port, that port will ignore the FD
switch setting.
For example, if FD is enabled and auto-negotiation is disabled on Ports
1 and 2 and enabled on Ports 3 and 4, then Ports 1 and 2 will operate at
full duplex, while Ports 3 and 4 will ignore the FD switch setting. The
duplex mode for Ports 3 and 4 will be determined through the auto-
negotiation process.
Half-Duplex Flow Control Switch (HDFL)
For ports operating at half duplex, the Radiance chassis stacking line
card provides an option to enable half-duplex flow control
(backpressure). When half-duplex flow control is activated, the
Radiance card generates a jamming pattern to force a collision on a port
if a buffer cannot be allocated for the port’s incoming packets. Half-
duplex flow control is enabled by default (OPEN).
The HDFL switch must be CLOSED to disable half-duplex flow
control on all four ports. The switch must be OPEN to enable HDFL on
all ports.
