flowcontrol
Use this command to enable flow control. Use the no form to disable flow con-
trol.
Syntax
flowcontrol
no flowcontrol
Default Setting
Flow control enabled
Command Mode
Interface Configuration (Ethernet, Port Channel)
Command Usage
> Flow control can eliminate frame loss by “blocking” traffic from end stations or
segments connected directly to the switch when its buffers fill. When enabled,
back pressure is used for half-duplex operation and IEEE 802.3x for full-duplex
operation.
> To enable flow control under autonegotiation, flowcontrol must be included in
the capabilities list for any port.
> To force operation to the mode specified in a flowcontrol command, use the no
negotiation command to disable auto-negotiation on the selected interface.
> Flow control should not be used if a port is connected to a hub. Otherwise flow
control signals will be propagated throughout the segment.
> Due to a hardware limitation, flow control only works on those ports located in the
same chip (ports 1-12 and ports 13-24). Cross-chip flow control does not work.
Example
The following example enables flow control on port 5.
Console(config)#interface ethernet 1/5
Console(config-if)#flowcontrol
Console(config-if)#no negotiation
Console(config-if)#
Related Commands
capabilities (flowcontrol, symmetric)
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