CCNA Examination good results depends mainly on noticing the main points, which is especially true of configurations involving specifically linked serial interfaces. And of course, it’s not enough to notice these information – you’ve received to know how to proceed about them!
A Cisco router is actually a DTE by default, but right connecting two DTEs which has a DCE/DTE cable will 먹튀검증 not be ample. In the following case in point, R1 and R3 are directly linked at their Serial1 interfaces. The line goes up briefly soon http://edition.cnn.com/search/?text=먹튀검증 after currently being opened, but the line protocol goes down following about thirty seconds.
R3(config-if)#int s1
R3(config-if)#ip handle 172.twelve.thirteen.three 255.255.255.0
R3(config-if)#no shutdown
2d18h: %Backlink-3-UPDOWN: Interface Serial1, changed point out to up
2d18h: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, changed state to up
R3(config-if)#
2d18h: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, transformed state to down
The situation is one of several routers has to act because the DCE to ensure that the road protocol to return up and stay awake. If this had been your CCNA / CCNP residence lab, you may just go over and consider the DTE/DCE cable to discover which router had the DCE conclusion with the cable attached. In this example, even though, we don’t have Actual physical usage of the routers. How can we explain to which router has the DCE stop with the cable connected?
R3#clearly show controller serial 1
High definition unit 1, idb = 0x1C44E8, driver construction at 0x1CBAC8
buffer dimensions 1524 High definition device 1, V.35 DCE cable
The show controller command presents us this data. (There’s lots extra output this with this particular command, however it’s unimportant for our functions.) The router with the DCE stop of your cable wants to supply a clock charge into the DTE, and we’ll do just that While using the interface-amount clockrate command.
R3#conf t
Enter configuration instructions, a person per line. Stop 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 link, always operate show interface initial. If you see The mix shown below, the relationship is bodily wonderful but logically down. That’s normally the result of a needed keepalive not getting present. With Frame Relay, it’s possibly an LMI difficulty, but with instantly related serial interfaces The problem is most likely the DCE stop of the relationship not giving clockrate.
R3#show interface serial 1
Serial1 is up, line protocol is down
Troubleshooting is a big Portion of the job, and it’s a major A part of the Cisco CCNA and CCNP systems likewise. Know your display and debug commands and you simply’re with your solution to passing the CCNA!