CCNA Test results is dependent largely on noticing the details, which is very true of configurations involving specifically connected serial interfaces. And naturally, it’s not enough to notice these aspects – you’ve obtained to know what to do about them!
A Cisco router is often a DTE by default, but right connecting two DTEs using a DCE/DTE cable isn't plenty of. In the next instance, R1 and R3 are immediately linked at their Serial1 interfaces. The road goes up briefly following staying opened, but the line protocol goes down following 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: %Backlink-3-UPDOWN: Interface Serial1, altered point out to up
2d18h: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, modified point out to up
R3(config-if)#
2d18h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, modified point out to down
The problem is that on the list of routers ought to act as the DCE to ensure that the road protocol to come back up and stay awake. If this ended up your CCNA / CCNP residence lab, you may just go more than and consider the DTE/DCE cable to view which router had the DCE end with the cable hooked up. In this instance, though, we don’t have Actual physical use of the routers. How can we convey to which router has the DCE stop on the cable connected?
R3#clearly show controller http://edition.cnn.com/search/?text=먹튀검증 serial one
High definition unit 1, idb = 0x1C44E8, driver composition at 0x1CBAC8
buffer measurement 1524 HD device 1, V.35 DCE cable
The show controller command gives us this details. (There’s a great deal a lot more output this with this particular command, nonetheless it’s unimportant for our functions.) The router Using the DCE conclude of the cable requirements to supply a clock level for the DTE, and we’ll just do that While using the interface-level clockrate command.
R3#conf t
Enter configuration commands, one per line. Stop with CNTL/Z.
R3(config)#int serial1
R3(config-if)#clockrate 56000
In only a few seconds, the road protocol goes up and stays up.
When troubleshooting a relationship, normally operate show interface 1st. If the thing is the combination shown below, the connection is bodily fantastic but logically down. That’s typically the results of a required keepalive not becoming current. With Frame Relay, it’s almost certainly an LMI difficulty, but with instantly linked serial interfaces The problem is most likely 먹튀검증 the DCE conclusion from the link not supplying clockrate.
R3#display interface serial 1
Serial1 is up, line protocol is down
Troubleshooting is a giant Section of the job, and it’s a huge Section of the Cisco CCNA and CCNP courses likewise. Know your present and debug instructions and you also’re in your way to passing the CCNA!