CCNA exam results depends largely on noticing the main points, https://www.washingtonpost.com/newssearch/?query=먹튀검증 and this is very true of configurations involving immediately related serial interfaces. And naturally, it’s not ample to notice these information – you’ve obtained to find out how to proceed about them!
A Cisco router can be a DTE by default, but straight connecting two DTEs with a DCE/DTE cable isn't enough. 먹튀검증 In the following case in point, R1 and R3 are right connected at their Serial1 interfaces. The road goes up briefly right after remaining opened, but the line protocol goes down immediately after about thirty seconds.
R3(config-if)#int s1
R3(config-if)#ip deal with 172.twelve.13.3 255.255.255.0
R3(config-if)#no shutdown
2d18h: %LINK-three-UPDOWN: Interface Serial1, adjusted point out to up
2d18h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, altered point out to up
R3(config-if)#
2d18h: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, adjusted point out to down
The challenge is that among the routers ought to act as being the DCE to ensure that the line protocol to come back up and stay awake. If this had been your CCNA / CCNP dwelling lab, you could potentially just go above and look at the DTE/DCE cable to determine which router experienced the DCE conclude of your cable attached. In this instance, though, we don’t have Actual physical entry to the routers. How can we explain to which router has the DCE conclude of your cable hooked up?
R3#demonstrate controller serial one
HD unit 1, idb = 0x1C44E8, driver construction at 0x1CBAC8
buffer sizing 1524 HD device 1, V.35 DCE cable
The show controller command offers us this facts. (There’s a good deal extra output this using this type of command, nevertheless it’s unimportant for our purposes.) The router With all the DCE conclude on the cable demands to provide a clock level to your DTE, and we’ll just do that Together with the interface-amount clockrate command.
R3#conf t
Enter configuration instructions, a person per line. Close with CNTL/Z.
R3(config)#int serial1
R3(config-if)#clockrate 56000
In just a few seconds, the road protocol goes up and stays up.
When troubleshooting a relationship, normally run present interface 1st. If the thing is The mix demonstrated underneath, the link is physically good but logically down. That’s usually the result of a desired keepalive not getting existing. With Frame Relay, it’s almost certainly an LMI problem, but with directly connected serial interfaces The problem is probably the DCE conclusion in the connection not providing clockrate.
R3#clearly show interface serial 1
Serial1 is up, line protocol is down
Troubleshooting is a giant Component of The task, and it’s a big part of the Cisco CCNA and CCNP courses in addition. Know your clearly show and debug instructions and you simply’re on your own solution to passing the CCNA!