CCNA Test results relies upon largely on noticing the small print, and this is very true of configurations involving instantly linked serial interfaces. And of course, it’s not enough to note these information – you’ve got to learn how to proceed about them!
A Cisco router can be a DTE by default, but directly connecting two DTEs using a DCE/DTE cable isn't ample. In the subsequent instance, R1 and R3 are immediately linked at their Serial1 interfaces. The road goes up briefly soon after being opened, but the line protocol goes down following about 30 seconds.
R3(config-if)#int s1
R3(config-if)#ip address 172.twelve.13.three 255.255.255.0
R3(config-if)#no shutdown
2d18h: %Website link-3-UPDOWN: Interface Serial1, transformed condition to up
2d18h: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, transformed condition to up
R3(config-if)#
2d18h: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, modified state to down
The issue is one of the routers really should act given that the DCE to ensure that the https://en.search.wordpress.com/?src=organic&q=먹튀검증 road protocol to return up and not sleep. If this have been your CCNA / CCNP home lab, you may just go above and think about the DTE/DCE cable to view which router experienced the DCE conclusion with the cable connected. In this example, nevertheless, we don’t have Actual physical access to the routers. How can we explain to which router has the DCE end in the cable attached?
R3#present controller serial 먹튀검증 one
High definition unit 1, idb = 0x1C44E8, driver composition at 0x1CBAC8
buffer dimension 1524 HD unit one, V.35 DCE cable
The show controller command provides us this details. (There’s a lot a lot more output that this using this type of command, but it surely’s unimportant for our applications.) The router Along with the DCE conclusion of your cable wants to produce a clock amount towards the DTE, and we’ll do just that With all the interface-degree clockrate command.
R3#conf t
Enter configuration commands, just one for every line. Finish with CNTL/Z.
R3(config)#int serial1
R3(config-if)#clockrate 56000
In just some seconds, the road protocol goes up and stays up.
When troubleshooting a connection, generally run exhibit interface very first. If you see The mix proven below, the link is physically great but logically down. That’s frequently the result of a essential keepalive not becoming existing. With Frame Relay, it’s in all probability an LMI concern, but with immediately connected serial interfaces The difficulty is more than likely the DCE finish with the relationship not providing clockrate.
R3#show interface serial one
Serial1 is up, line protocol is down
Troubleshooting is a large part of The task, and it’s a huge A part of the Cisco CCNA and CCNP packages at the same time. Know your clearly show and debug commands so you’re on the technique to passing the CCNA!