Command Line Interface
4-140
4
back pressure is used for half-duplex operation and IEEE 802.3-2005
(formally IEEE 802.3x) for full-duplex operation.
• To force flow control on or off (with the flowcontrol or no flowcontrol
command), use the no negotiation command to disable auto-negotiation on
the selected interface.
• When using the negotiation command to enable auto-negotiation, the
optimal settings will be determined by the capabilities command. To enable
flow control under auto-negotiation, “flowcontrol” must be included in the
capabilities list for any port
• Avoid using flow control on a port connected to a hub unless it is actually
required to solve a problem. Otherwise back pressure jamming signals may
degrade overall performance for the segment attached to the hub.
Example
The following example enables flow control on port 5.
Related Commands
negotiation (4-137)
capabilities (flowcontrol, symmetric) (4-138)
media-type
This command forces the port type selected for combination ports 17-18. Use the no
form to restore the default mode.
Syntax
media-type mode
no media-type
mode
• copper-forced - Always uses the built-in RJ-45 port.
• sfp-forced - Always uses the SFP port (even if module not installed).
• sfp-preferred-auto - Uses SFP port if both combination types are
functioning and the SFP port has a valid link.
Default Setting
sfp-preferred-auto
Command Mode
Interface Configuration (Ethernet)
Console(config)#interface ethernet 1/5
Console(config-if)#flowcontrol
Console(config-if)#no negotiation
Console(config-if)#