RAD Data comm E1 Interface Converter RIC-E1 - Manual (Page 56)

Appendix C IR-ETH/V Interface Module RIC-E1 Installation and Operation Manual
C-6 Installation and Operation
Backpressure and Flow Control
DIP switch SW1/4 enables or disables both backpressure and flow control.
When the IR-ETH/V is set to half duplex, backpressure is active, and when the IR-
ETH/V is set to full duplex, flow control is active.
Full duplex flow control activation requires autonegotiation to be enabled.
Backpressure is the term given when the buffer is filled from the LAN faster than it
is able to transmit to the WAN. In order to prevent packet loss, collisions are
forced into the LAN, which causes the link partners to go into backoff before
attempting to retransmit. Reducing, in effect, the traffic coming through the
interface.
Flow control is active only in full duplex mode. When the buffer is filled from the
LAN faster than it is able to transmit to the WAN, pause frames are sent to the
LAN, ordering the LAN to stop for a time interval indicated by the pause frame
until transmission starts again.
To use the flow control option, the link partners (switches etc.) should support flow
control.
LED Indicators
Table C-4 lists the IR-ETH/V LED indicators and describes their functions.
Table C-4. IR-ETH/V LED Indicators
LED Color Function
LINK Green ON – LAN is connected
ACT Yellow Blinks – Transmit/receive activity is detected on the Ethernet link
100M Green ON – LAN is operating at 100 Mbps
Connecting the LAN
Use either a straight cable or a cross cable for the LAN connection.
Use a cross cable when connecting to a port that does not implement the
crossover function internally. Otherwise, use a straight cable.
Hubs usually implement the crossover function internally, while NICs and other
devices do not.
Note
Note
Note
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