CCNA Test accomplishment relies upon mainly on noticing the main points, which is especially true of configurations involving specifically linked serial interfaces. And naturally, it’s not enough to notice these aspects – you’ve got to grasp how to proceed about them!
A Cisco router is often a DTE by default, but straight connecting two DTEs with a DCE/DTE cable is not ample. In the subsequent example, R1 and R3 are straight related at their Serial1 interfaces. The line goes up briefly following currently being opened, but the road protocol goes down soon after about 30 seconds.
R3(config-if)#int s1
R3(config-if)#ip deal with 172.12.thirteen.3 255.255.255.0
R3(config-if)#no shutdown
2d18h: %Connection-3-UPDOWN: Interface Serial1, improved state http://www.thefreedictionary.com/먹튀검증 to up
2d18h: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, transformed point out to up
R3(config-if)#
2d18h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, altered point out to down
The problem is that one of several routers must act as being the DCE in order for the line protocol to return up and stay up. If this were being your CCNA / CCNP house lab, you can just go above and look at the DTE/DCE cable to find out which router experienced the DCE close from the cable hooked up. In this example, while, we don’t have Bodily access to the routers. How can we notify which router has the DCE end with the cable hooked up?
R3#display controller serial 1
High definition device 1, idb = 0x1C44E8, driver 먹튀검증 composition at 0x1CBAC8
buffer measurement 1524 High definition unit one, V.35 DCE cable
The display controller command presents us this info. (There’s lots far more output this using this type of command, but it’s unimportant for our needs.) The router Along with the DCE conclusion on the cable requires to provide a clock amount for the DTE, and we’ll do just that While using the interface-amount clockrate command.
R3#conf t
Enter configuration commands, just one per line. Close with CNTL/Z.
R3(config)#int serial1
R3(config-if)#clockrate 56000
In just a couple seconds, the line protocol goes up and stays up.
When troubleshooting a connection, generally run exhibit interface very first. If you see The mixture shown down below, the relationship is physically wonderful but logically down. That’s generally the result of a essential keepalive not being current. With Frame Relay, it’s probably an LMI issue, but with specifically linked serial interfaces The difficulty is most certainly the DCE end with the link not giving clockrate.
R3#present interface serial 1
Serial1 is up, line protocol is down
Troubleshooting is a major Element of The work, and it’s a major A part of the Cisco CCNA and CCNP programs at the same time. Know your display and debug commands so you’re on your approach to passing the CCNA!