Cisco CCNA / CCNP Certification Exam: Troubleshooting Immediate Serial Connections
A primary topic of your respective CCNA and CCNP CIT exams will probably be connecting Cisco routers straight by way of their Serial interfaces, and even though the configuration is easy, there are many essential particulars and display 인스타 좋아요 commands you will need to know in order to pass the examinations and configure this successfully in output and home lab networks. Permit’s Look into a sample configuration.
Connecting Cisco routers directly by way of their Serial interfaces performs very well as soon as you get it running – and getting such a connection up and running is not hard plenty of. You should utilize demonstrate controller serial x to learn which endpoint is performing given that the DCE, and it’s the DCE that need to be configured While using the clockrate command.
R3#clearly show controller serial one
High definition unit 1, idb = 0x11B4DC, driver framework at 0x121868
buffer dimensions 1524 High definition device one, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip tackle 172.12.13.three 255.255.255.0
R3(config-if)#clockrate 56000
R3(config-if)#no shut
Failure to configure the clockrate has some exciting outcomes concerning the Actual physical and sensible condition on the interfaces. Enable’s get rid of the clockrate from R3 and see what happens.
R3(config)#int s1
R3(config-if)#no clockrate 56000
R3(config-if)#
18:02:19: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, changed condition to down
The road protocol doesn’t fall instantly, but it does fall. Enable’s operate show interface serial1 to compare the physical and reasonable interface states.
R3#clearly show int serial1
Serial1 is up, line protocol is http://www.bbc.co.uk/search?q=인스타 팔로워 구매 down
Physically, the interface is fine, Hence the Bodily interface is up. It’s only the reasonable Element of the interface – the line protocol – that may be down. It’s precisely the same situation on R1.
R1#show inter serial1
Whilst a router misconfiguration will be the most likely reason for a serial link issue, that’s not the only real cause of clocking troubles. Cisco’s Web site documentation mentions CSU/DSU misconfiguration, out-of-spec cables, bad patch panel connections, and connecting a lot of cables with each other as other explanations for clocking complications. Still, the number 1 basis for clocking complications in my knowledge is simply forgetting to configure the clockrate command!