Cisco CCNA / CCNP Certification Exam: Troubleshooting Immediate Serial Connections
A first-rate topic of one's CCNA and CCNP CIT tests will likely be connecting Cisco routers directly via their Serial interfaces, and even though the configuration is simple, there are several essential information and exhibit instructions you must know in an effort to move the exams and configure this properly in output and residential lab networks. Let’s Consider a sample configuration.
Connecting Cisco routers specifically via their Serial interfaces functions really well after you get it running – and receiving this kind of relationship up and jogging is simple adequate. You should utilize exhibit controller serial x to see which endpoint is acting given that the DCE, and it’s the DCE that needs to be configured with the clockrate command.
R3#clearly show controller serial 1
High definition unit one, idb = 0x11B4DC, driver framework at 0x121868
buffer sizing 1524 HD unit one, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip handle 172.12.thirteen.3 255.255.255.0
R3(config-if)#clockrate 56000
R3(config-if)#no shut
Failure to configure the clockrate has some interesting outcomes concerning the physical and sensible point out in the interfaces. Permit’s http://www.thefreedictionary.com/인스타 팔로워 구매 take away the clockrate from R3 and see what comes about.
R3(config)#int s1
R3(config-if)#no clockrate 56000
R3(config-if)#
18:02:19: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, modified point out to down
The road protocol doesn’t fall straight away, but it does fall. Let’s operate show interface serial1 to match the Bodily and reasonable interface states.
R3#present int serial1
Serial1 is up, line protocol is down
Bodily, the interface is fine, so the physical interface is up. It’s just the rational A part of the interface – the road protocol – that's down. It’s the same scenario on R1.
R1#show inter serial1
While a router misconfiguration would be the most likely 인스타 팔로워 explanation for a serial link concern, that’s not the sole reason for clocking troubles. Cisco’s Site documentation mentions CSU/DSU misconfiguration, out-of-spec cables, negative patch panel connections, and connecting a lot of cables alongside one another as other reasons for clocking complications. Still, the primary basis for clocking complications in my knowledge is simply forgetting to configure the clockrate command!