CCNA Examination good results depends mainly on noticing the main points, which is especially true of configurations involving immediately related serial interfaces. And of course, it’s not enough to https://en.search.wordpress.com/?src=organic&q=먹튀검증 note these aspects – you’ve got to be aware of how to proceed about them!
A Cisco router is usually a DTE by default, but specifically connecting two DTEs which has a DCE/DTE cable just isn't adequate. In the next illustration, R1 and R3 are specifically related at their Serial1 interfaces. The road goes up briefly 먹튀검증 following staying opened, but the road protocol goes down just after about thirty seconds.
R3(config-if)#int s1
R3(config-if)#ip tackle 172.twelve.13.three 255.255.255.0
R3(config-if)#no shutdown
2d18h: %Backlink-3-UPDOWN: Interface Serial1, adjusted point out to up
2d18h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, transformed state to up
R3(config-if)#
2d18h: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, improved condition to down
The challenge is usually that one of the routers must act given that the DCE in order for the line protocol to come up and stay awake. If this have been your CCNA / CCNP dwelling lab, you could possibly just go above and look at the DTE/DCE cable to see which router experienced the DCE conclude with the cable hooked up. In this example, even though, we don’t have Actual physical use of the routers. How can we explain to which router has the DCE end on the cable attached?
R3#clearly show controller serial one
High definition unit one, idb = 0x1C44E8, driver framework at 0x1CBAC8
buffer size 1524 HD unit 1, V.35 DCE cable
The demonstrate controller command presents us this data. (There’s a whole lot a lot more output this using this type of command, but it surely’s unimportant for our purposes.) The router Along with the DCE conclude of your cable demands to supply a clock fee into the DTE, and we’ll do exactly that with the interface-amount clockrate command.
R3#conf t
Enter configuration commands, one particular per line. Finish with CNTL/Z.
R3(config)#int serial1
R3(config-if)#clockrate 56000
In just a few seconds, the line protocol goes up and stays up.
When troubleshooting a link, always run present interface first. If you see The mix revealed under, the connection is bodily fantastic but logically down. That’s frequently the result of a needed keepalive not staying existing. With Frame Relay, it’s in all probability an LMI situation, but with instantly related serial interfaces The difficulty is more than likely the DCE conclude of the connection not providing clockrate.
R3#demonstrate interface serial 1
Serial1 is up, line protocol is down
Troubleshooting is an enormous Section of The task, and it’s a major Component of the Cisco CCNA and CCNP systems too. Know your display and debug commands so you’re on your own solution to passing the CCNA!