Cisco CCNA / CCNP Certification Exam: Troubleshooting Immediate Serial Connections
A first-rate subject of your respective CCNA and CCNP CIT tests might be connecting Cisco routers right via their Serial interfaces, and while the configuration is simple, there are a few essential information and display instructions you should know so as to go the tests and configure this effectively in production and home lab networks. Allow’s Examine a sample configuration.
Connecting Cisco routers right by way of their Serial interfaces performs really well 인스타 팔로워 as soon as you get it running – and acquiring this type of connection up and working is not hard enough. You should use present controller serial x to understand which endpoint is performing as the DCE, and it’s the DCE that has to be configured Along with the clockrate command.
R3#present controller serial 1
High definition device one, idb = 0x11B4DC, driver construction at 0x121868
buffer size 1524 High definition device one, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip handle 172.12.thirteen.three 255.255.255.0
R3(config-if)#clockrate 56000
R3(config-if)#no shut
Failure to configure the clockrate has some exciting effects regarding the physical and rational condition of your interfaces. Let’s take away the clockrate from R3 and see what occurs.
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 condition to down
The road protocol doesn’t drop instantly, https://en.wikipedia.org/wiki/?search=인스타 팔로워 구매 but it surely does drop. Let’s operate clearly show interface serial1 to check the Bodily and sensible interface states.
R3#present int serial1
Serial1 is up, line protocol is down
Physically, the interface is okay, And so the physical interface is up. It’s only the rational A part of the interface – the road protocol – that's down. It’s the identical predicament on R1.
R1#exhibit inter serial1
When a router misconfiguration could be the probably reason for a serial connection concern, that’s not the one cause for clocking difficulties. Cisco’s Web site documentation mentions CSU/DSU misconfiguration, out-of-spec cables, bad patch panel connections, and connecting too many cables jointly as other causes for clocking issues. However, the number 1 cause of clocking complications in my expertise is actually forgetting to configure the clockrate command!