Cisco CCNA / CCNP Certification Exam: Troubleshooting Immediate Serial Connections
A primary subject of the CCNA and CCNP CIT tests is going to be connecting Cisco routers directly by using their Serial interfaces, and whilst the configuration is 메이저사이트 easy, there are numerous essential specifics and show commands it's essential to know as a way to pass the tests and configure this efficiently in production and residential lab networks. Enable’s Check out a sample configuration.
Connecting Cisco routers straight by using their Serial interfaces is effective really well when you get it managing – and finding this type of relationship up and jogging is a snap ample. You may use exhibit controller serial x to discover which endpoint is acting as the DCE, and it’s the DCE that have to be configured With all the clockrate command.
R3#exhibit controller serial 1
High definition unit 1, idb = 0x11B4DC, driver construction at 0x121868
buffer sizing 1524 HD unit https://en.search.wordpress.com/?src=organic&q=토토사이트 one, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip tackle 172.twelve.thirteen.three 255.255.255.0
R3(config-if)#clockrate 56000
R3(config-if)#no shut
Failure to configure the clockrate has some interesting effects regarding the Actual physical and reasonable condition with the interfaces. Let’s get rid of the clockrate from R3 and find out what transpires.
R3(config)#int s1
R3(config-if)#no clockrate 56000
R3(config-if)#
18:02:19: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, changed point out to down
The line protocol doesn’t fall instantly, nonetheless it does drop. Enable’s run exhibit interface serial1 to match the Actual physical and sensible interface states.
R3#present int serial1
Serial1 is up, line protocol is down
Physically, the interface is ok, Hence the physical interface is up. It’s just the sensible Element of the interface – the road protocol – that is certainly down. It’s the same condition on R1.
R1#present inter serial1
While a router misconfiguration could be the more than likely reason behind a serial relationship concern, that’s not the one cause for clocking difficulties. Cisco’s Site documentation mentions CSU/DSU misconfiguration, out-of-spec cables, bad patch panel connections, and connecting too many cables collectively as other factors for clocking difficulties. However, the number 1 cause of clocking issues in my practical experience is solely forgetting to configure the clockrate command!