Cisco CCNA / CCNP Certification Examination: Troubleshooting Immediate Serial Connections
A primary matter of your CCNA and CCNP CIT exams might be connecting Cisco routers directly by using their Serial interfaces, and whilst the configuration is easy, there are several crucial information and display instructions you need to know as a way to go the tests and configure this efficiently in creation and residential lab networks. Permit’s take a look at a sample configuration.
Connecting Cisco routers immediately by using their Serial interfaces performs really well once you get it managing – and getting this type of link up and running is a snap adequate. You can utilize show controller serial x to determine which endpoint is acting since the DCE, and it’s the DCE that has to be configured Along with the clockrate command.
R3#clearly show controller serial one
HD device one, idb = 0x11B4DC, driver composition at 0x121868
buffer dimension 1524 HD unit 1, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip address 172.12.13.three 255.255.255.0
R3(config-if)#clockrate 56000
R3(config-if)#no shut
Failure to configure the https://en.wikipedia.org/wiki/?search=인스타 팔로워 구매 clockrate has some exciting consequences regarding the physical and logical point out on the interfaces. Enable’s take out the clockrate from R3 and see what takes place.
R3(config)#int s1
R3(config-if)#no clockrate 56000
R3(config-if)#
18:02:19: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, improved state to down
The line protocol doesn’t drop straight away, but it does fall. Enable’s run clearly show interface serial1 to compare the Actual physical and logical interface states.
R3#exhibit int serial1
Serial1 is up, line protocol is down
Physically, the interface is okay, Therefore the physical interface is up. It’s just the sensible Component of the interface – the road protocol – which is 인스타 좋아요 down. It’s the identical scenario on R1.
R1#demonstrate inter serial1
Even though a router misconfiguration is the most certainly explanation for a serial connection problem, that’s not the only cause for clocking problems. Cisco’s website documentation mentions CSU/DSU misconfiguration, out-of-spec cables, poor patch panel connections, and connecting too many cables with each other as other factors for clocking problems. Still, the primary reason behind clocking problems in my encounter is solely forgetting to configure the clockrate command!