Cisco Systems 1604 manual Verifying the Ethernet Interface Configuration

Chapter 3 Configuring the Cisco 1604 Router

Verifying the Ethernet Interface Configuration

Step 2 Bring up the interface. This command changes the state of the interface from administratively down to up.

robo-austin(config-if)# no shutdown

Verifying the Ethernet Interface Configuration

To verify the Cisco 1604’s Ethernet interface configuration:

Step 1 Enter the show ip interface brief command, which enables you to quickly check the status of all router interfaces.

The field “administratively down” means that the interface is configured with the shutdown command.

Step 2 To bring the interface up, you must enter the no shutdown command. In the example below, the Status column refers to the ability to physically connect the network at Layer 1—needed for getting clocks (timing signals) and carrier signals. The Protocol column refers to the ability to see traffic flow, which typically occurs at the data link layer. For example, the Ethernet interface sends a loopback Ethernet packet out to itself through the Ethernet LAN:

robo-austin#show ip interface brief
Interface	IP-Address	OK? Method	Status	Protocol
BRI0	unassigned	YES unset	administratively down down
BRI0:1	unassigned	YES unset	administratively down down
BRI0:2	unassigned	YES unset	administratively down down
Ethernet0	10.1.4.1	YES manual	up	up
Serial0	unassigned	YES unset	administratively down down

In the next example, note that the status is up but the protocol is down. The following logging message appears at 00:40:20: “Unit 0, lost carrier. Transceiver problem?.” After the Ethernet cable is plugged into the Ethernet port, the interface comes up. See 00:40:25.

robo-austin#show ip interface brief
Interface	IP-Address	OK?	Method	Status	Protocol
BRI0	unassigned	YES	unset	administratively down down
BRI0:1	unassigned	YES	unset	administratively down down
BRI0:2	unassigned	YES	unset	administratively down down
Ethernet0	10.1.4.1	YES	manual	up	down
Serial0	unassigned	YES	unset	administratively down down
robo-austin#
00:40:20: %QUICC_ETHER-1-LOSTCARR: Unit 0,			lost carrier. Transceiver problem?

00:40:25: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0, changed sta te to up

robo-austin#

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