CCNA exam results is dependent mostly on noticing the small print, which is especially true of configurations involving directly related serial interfaces. And of course, it’s not enough to note these particulars – you’ve received to understand what to do about them!
A Cisco router is often a DTE by default, but specifically connecting two DTEs that has a DCE/DTE cable is not really plenty of. In the next illustration, R1 and R3 are specifically connected at their Serial1 interfaces. The road goes up briefly following currently being opened, but the line protocol goes down after about thirty seconds.
R3(config-if)#int s1
R3(config-if)#ip handle 172.12.thirteen.3 255.255.255.0
R3(config-if)#no shutdown
2d18h: %LINK-three-UPDOWN: Interface Serial1, altered state to up
2d18h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, altered state to up
R3(config-if)#
2d18h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, improved point out to down
The situation is that among the list of routers really should act given that the DCE in order for the line protocol to come up and stay up. If this have been your CCNA / CCNP property lab, you could just go in excess of and consider the DTE/DCE 토토먹튀 cable to discover which router experienced the DCE conclude with the cable hooked up. In this instance, although, we don’t have Bodily entry to the routers. How can we tell which router has the DCE end with the cable connected?
R3#demonstrate controller serial one
High definition device 1, idb = 0x1C44E8, driver framework at 0x1CBAC8
buffer sizing 1524 High definition device one, V.35 DCE cable
The demonstrate controller command offers us this facts. (There’s a great deal far more output that this with this particular command, but it surely’s unimportant for our purposes.) The router with the DCE close from the cable wants to provide a clock charge to the DTE, and we’ll do exactly that Together with the interface-level clockrate command.
R3#conf t
Enter configuration instructions, one particular 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, often operate show interface initial. If the thing is The mix proven below, the connection is physically fine but logically down. That’s typically the results of a essential keepalive not remaining present. With Frame Relay, it’s in all probability an LMI challenge, but with immediately connected serial interfaces the issue is almost certainly the DCE finish in the link not providing clockrate.
R3#exhibit interface serial one
Serial1 is up, line protocol is down
Troubleshooting is a giant Portion of the job, and it’s an enormous Element of the Cisco CCNA and CCNP packages likewise. Know your exhibit and debug instructions and also you’re http://www.bbc.co.uk/search?q=먹튀검증 on the way to passing the CCNA!