CCNA exam success depends largely on noticing the main points, and this is very true of configurations involving specifically related serial interfaces. And naturally, it’s not https://mthunter87.com/ adequate to note these details – you’ve got to understand how to proceed about them!
A Cisco router is usually a DTE by default, but specifically connecting two DTEs with a DCE/DTE cable is not sufficient. In the subsequent example, R1 and R3 are directly linked at their Serial1 interfaces. The road goes up briefly right after remaining opened, but the line protocol goes down after about thirty seconds.
R3(config-if)#int s1
R3(config-if)#ip handle 172.twelve.thirteen.3 255.255.255.0
R3(config-if)#no shutdown
2d18h: %Hyperlink-three-UPDOWN: Interface Serial1, improved point out to up
2d18h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, modified condition to up
R3(config-if)#
2d18h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, adjusted condition to down
The challenge is one of the routers must act given that the DCE in order for the line protocol to come up and stay up. If this were your CCNA / CCNP residence lab, you could just go over and consider the DTE/DCE cable to see which router experienced the DCE conclusion with the cable hooked up. In this example, however, we don’t have physical access to the routers. How can we tell which router has the DCE end on the cable hooked up?
R3#show controller https://www.washingtonpost.com/newssearch/?query=먹튀검증 serial 1
High definition device one, idb = 0x1C44E8, driver construction at 0x1CBAC8
buffer measurement 1524 High definition unit 1, V.35 DCE cable
The exhibit controller command gives us this facts. (There’s a lot additional output that this using this command, nonetheless it’s unimportant for our purposes.) The router While using the DCE finish on the cable requirements to produce a clock fee towards the DTE, and we’ll just do that with the interface-degree clockrate command.
R3#conf t
Enter configuration commands, a person per line. Finish with CNTL/Z.
R3(config)#int serial1
R3(config-if)#clockrate 56000
In only a few seconds, the line protocol goes up and stays up.
When troubleshooting a connection, constantly run clearly show interface initially. If the thing is The mix revealed under, the connection is bodily good but logically down. That’s frequently the results of a needed keepalive not getting current. With Frame Relay, it’s in all probability an LMI situation, but with immediately related serial interfaces The difficulty is probably the DCE finish on the link not providing clockrate.
R3#clearly show interface serial 1
Serial1 is up, line protocol is down
Troubleshooting is a huge part of the job, and it’s a giant Section of the Cisco CCNA and CCNP packages too. Know your exhibit and debug commands and also you’re with your strategy to passing the CCNA!