Flow Control - Bay Networks BayStack 281 Series Manual

Flow Control

893-00965-A
The BayStack 281xx switch uses a proprietary flow-control feature on
100 Mb/s full-duplex links to control traffic and avoid congestion on the link.
If the receive port buffer becomes full, the BayStack 281xx switch issues a
flow-control signal to the device at the other end of the link to suspend
transmission. When the receive buffer is no longer full, the BayStack 281xx
switch issues a signal to the end station to resume the transmission.
These flow-control signals may not be supported by other vendors' full-duplex
product implementations, so be aware of possible problems when congestion
occurs on the ports operating in this mode. Typically, these flow-control signals
are interpreted as CRC errors (causing loss of the packet that was on the wire
when the flow control signal was sent), but they should have no great impact on
the receiving device.
If you experience interoperability problems with other vendors' equipment
while using the full-duplex implementation, disable flow control on the
100 Mb/s full-duplex port connected to the interoperable device. If the problem
persists, reconfigure the associated BayStack 281xx switch (and the adapter
card installed in the attached station) for half-duplex operation. For instructions
on how to disable and enable flow control, see "Modifying Switch Port Flow
Control" on page 4-20 in Chapter 4, "Configuring the BayStack 281xx
Switch."
NOTE: BayStack 28115/ADV switches with revision G hardware allow flow
control to be disabled.
BayStack 281xx Switch Operation
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