Cisco Systems A9014CFD manual Setting the Speed and Duplex Mode, Gigabitethernet 0/1, Cdp enable

Chapter 7 Configuring Gigabit Ethernet Interfaces

Setting the Speed and Duplex Mode

	Command	Purpose
Step 3
	interface gigabitethernet slot/port	Specifies the port adapter type and the location of the interface to be
		configured. The slot is always 0 and the port is the number of the port.
	Example:
	Router(config)# interface
	gigabitethernet 0/1
Step 4
	cdp enable	Enables Cisco Discovery Protocol on the router, use the cdp enable
		command.
	Example:
	Router(config-if)# cdp enable
Step 5
	end	Exits configuration mode.
	Example:
	Router(config-if)# end
	Router#

Setting the Speed and Duplex Mode

The Gigabit Ethernet ports of the Cisco ASR 901 router can run in full or half- duplex mode—100 Mbps or 1000 Mbps (1 Gbps). The Cisco ASR 901 router has an autonegotiation feature that allows the router to negotiate the speed and duplex mode with the corresponding interface at the other end of the connection.

Autonegotiation is the default setting for the speed and transmission mode.

When you configure an interface speed and duplex mode, follow these guidelines:

•If both ends of the line support autonegotiation, use the default autonegotiation settings.

•When autonegotiation is turned on, it autonegotiates both speed and the duplex mode.

•If one interface supports autonegotiation, and the interface at the other end does not, configure the duplex mode and speed on both interfaces. If you use the autonegotiation setting on the supported side, the duplex mode setting is set at half-duplex.

•For Giga Ethernet ports with copper cable, autonegotiation should always be enabled for operating at 1000Mbps speed.

•Auto-negotiation must be enabled for 1000M full duplex Gigabit Ethernet devices; otherwise behavior is unpredictable.

Note Speed and duplex can be configured only on the following interfaces:

•Copper gigabitethernet interfaces (0/0-3)

•Combo gigabitethernet interface (0/4-7), when the media type is configured as RJ-45

Note In the following procedure, press the Return key after each step unless otherwise noted. At any time, you can exit the privileged level and return to the user level by entering disable at the Router# prompt.

Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide

7-2 OL-23826-09