Cisco CCNA / CCNP Certification Examination: Troubleshooting Direct Serial Connections
A first-rate subject of the CCNA and CCNP CIT tests might be connecting Cisco routers specifically via their Serial interfaces, and although the configuration is simple, there are numerous very important details and display instructions you need to know https://www.washingtonpost.com/newssearch/?query=인스타 팔로워 구매 in order to move the exams and configure this productively in generation and residential lab networks. Permit’s Have a look at a sample configuration.
Connecting Cisco routers straight by way of their Serial interfaces is effective very well as you get it functioning – and receiving such a relationship up and running is easy sufficient. You may use clearly 인스타 좋아요 show controller serial x to understand which endpoint is performing given that the DCE, and it’s the DCE that must be configured Together with the clockrate command.
R3#display controller serial one
HD device 1, idb = 0x11B4DC, driver structure at 0x121868
buffer size 1524 High definition device 1, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip handle 172.twelve.13.three 255.255.255.0
R3(config-if)#clockrate 56000
R3(config-if)#no shut
Failure to configure the clockrate has some attention-grabbing effects regarding the Actual physical and logical state in the interfaces. Let’s clear away the clockrate from R3 and find out what happens.
R3(config)#int s1
R3(config-if)#no clockrate 56000
R3(config-if)#
18:02:19: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, modified state to down
The road protocol doesn’t drop quickly, but it surely does drop. Allow’s operate exhibit interface serial1 to match the Bodily and rational interface states.
R3#exhibit int serial1
Serial1 is up, line protocol is down
Physically, the interface is ok, Hence the physical interface is up. It’s only the reasonable Section of the interface – the line protocol – that is definitely down. It’s precisely the same situation on R1.
R1#exhibit inter serial1
Though a router misconfiguration will be the probably explanation for a serial link concern, that’s not the only cause of clocking difficulties. Cisco’s Site documentation mentions CSU/DSU misconfiguration, out-of-spec cables, bad patch panel connections, and connecting too many cables together as other explanations for clocking problems. Still, the number one basis for clocking troubles in my encounter is actually forgetting to configure the clockrate command!