CCNA Test good results depends largely on noticing the small print, and http://edition.cnn.com/search/?text=먹튀검증 this is very true of configurations involving directly connected serial interfaces. Not to mention, it’s not sufficient to notice these information – you’ve received to grasp what to do about them!
A Cisco router is usually a DTE by default, but immediately connecting two DTEs that has a DCE/DTE cable is not really plenty of. In the following illustration, R1 and R3 are instantly connected at their Serial1 interfaces. The line goes up briefly following remaining opened, but the road protocol goes down soon after about 30 seconds.
R3(config-if)#int s1
R3(config-if)#ip address 172.12.13.3 255.255.255.0
R3(config-if)#no shutdown
2d18h: %Backlink-three-UPDOWN: Interface Serial1, adjusted state to up
2d18h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, altered condition to up
R3(config-if)#
2d18h: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, adjusted condition to down
The issue is the fact that one of several routers needs to act given that the DCE to ensure that the line protocol to return up and stay awake. If this were being your CCNA / CCNP household lab, you could potentially just go above and look at the DTE/DCE cable to view which router had the DCE end in the cable hooked up. In this instance, though, we don’t have Actual physical access to the routers. How can we convey to which router has the DCE finish on the cable attached?
R3#display controller serial one
High definition unit 1, idb = 0x1C44E8, driver composition at 0x1CBAC8
buffer measurement 1524 High definition device one, V.35 DCE cable
The exhibit controller command presents us this information and facts. (There’s lots much more output this 토토먹튀 with this particular command, but it surely’s unimportant for our uses.) The router with the DCE conclusion on the cable requirements to supply a clock rate to the DTE, and we’ll do just that With all the interface-stage clockrate command.
R3#conf t
Enter configuration commands, just one for every 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, normally operate present interface first. If you see the combination revealed under, the connection is bodily high-quality but logically down. That’s frequently the results of a desired keepalive not staying present. With Frame Relay, it’s possibly an LMI concern, but with specifically connected serial interfaces The problem is probably the DCE end with the connection not providing clockrate.
R3#demonstrate interface serial one
Serial1 is up, line protocol is down
Troubleshooting is a giant Component of The task, and it’s a big Element of the Cisco CCNA and CCNP courses likewise. Know your display and debug instructions and you’re with your technique to passing the CCNA!