39
Configuring Interfaces
Configuring Ethernet Interfaces
Beginning in privileged EXEC mode, follow these steps to configure amount of power budgeted to a powered device
connected to a specific PoE port:
To return to the default setting, use the no power inline consumption interface configuration command.
Configuring IEEE 802.3x Flow Control
802.3x flow control enables connected Ethernet ports to control traffic rates during congestion by allowing congested
nodes to pause link operation at the other end. If one port experiences congestion and cannot receive any more traffic,
it notifies the other port by sending a pause frame to stop sending until the condition clears. Upon receipt of a pause
frame, the sending device stops sending any data packets, which prevents any loss of data packets during the
congestion period.
Note: Ports can receive, but not send, pause frames.
You use the flowcontrol interface configuration command to set the interface’s ability to receive pause frames to on,
off, or desired. The default state is off.
When set to desired, an interface can operate with an attached device that is required to send flow-control packets or
with an attached device that is not required to but can send flow-control packets.
These rules apply to 802.3x flow control settings on the device:
receive on (or desired): The port cannot send pause frames but can operate with an attached device that is required
to or can send pause frames; the port can receive pause frames.
receive off: 802.3x flow control does not operate in either direction. In case of congestion, no indication is given to
the link partner, and no pause frames are sent or received by either device.
Beginning in privileged EXEC mode, follow these steps to configure 802.3x flow control on an interface:
Command Purpose
1. configure terminal Enter global configuration mode.
2. no cdp run (Optional) Disable CDP.
3. interface interface-id Specify the physical port to be configured, and enter interface
configuration mode.
4. power inline consumption wattage Configure the power consumption of a powered device connected to a
PoE port on the switch. The range for each device is 4000 to 15400 mW.
The default is 15400 mW.
5. end Return to privileged EXEC mode.
6. show power inline consumption Display the power consumption status.
7. copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
1. configure terminal Enter global configuration mode
2. interface interface-id Specify the physical interface to be configured, and enter
interface configuration mode.
3. no shutdown Enable the port, if necessary. By default, UNIs and ENIs are
disabled, and NNIs are enabled.
4. flowcontrol {receive} {on | off | desired} Configure the 802.3x flow control mode for the port.