CCNA Test results depends mostly on noticing the details, which is especially true of configurations involving immediately connected serial interfaces. Not to mention, it’s not more than enough to note these specifics – you’ve bought to grasp what to do about them!
A Cisco router is actually a DTE by default, but straight connecting two DTEs with a DCE/DTE cable is just not adequate. In the subsequent example, R1 and R3 are straight connected at their Serial1 interfaces. The road goes up briefly right after staying opened, but the road protocol goes down after about thirty seconds.
R3(config-if)#int s1
R3(config-if)#ip handle 172.12.13.three 255.255.255.0
R3(config-if)#no shutdown
2d18h: %Hyperlink-three-UPDOWN: Interface Serial1, changed state to up
2d18h: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, changed point out to up
R3(config-if)#
2d18h: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, changed condition to down
The issue is always that on the list of routers must act because the DCE to ensure that the line protocol to return up and not sleep. If this have been your CCNA / CCNP dwelling lab, you might just go over and consider the DTE/DCE cable to find out which router had the DCE conclude with the cable attached. In this example, though, we don’t have Bodily entry to the routers. How can we tell which router has the DCE conclusion from the cable attached?
R3#display controller serial 1
High definition unit 1, idb = 0x1C44E8, driver structure at 0x1CBAC8
buffer sizing 1524 High definition unit one, 토토검증 V.35 DCE cable
The demonstrate controller command provides us this information. (There’s a whole lot more output this using https://www.washingtonpost.com/newssearch/?query=먹튀검증 this command, but it really’s unimportant for our needs.) The router While using the DCE conclusion on the cable demands to provide a clock price on the DTE, and we’ll just do that Using the interface-stage clockrate command.
R3#conf t
Enter configuration commands, a person for each line. End with CNTL/Z.
R3(config)#int serial1
R3(config-if)#clockrate 56000
In just a couple seconds, the road protocol goes up and stays up.
When troubleshooting a link, generally operate exhibit interface 1st. If you see The mixture shown underneath, the relationship is physically great but logically down. That’s commonly the results of a essential keepalive not staying present. With Frame Relay, it’s most likely an LMI concern, but with specifically related serial interfaces the issue is probably the DCE conclude from the link not supplying clockrate.
R3#display interface serial one
Serial1 is up, line protocol is down
Troubleshooting is a big A part of The task, and it’s a huge Component of the Cisco CCNA and CCNP programs at the same time. Know your display and debug instructions therefore you’re on your approach to passing the CCNA!
