Cisco CCNA / CCNP Certification Examination: Troubleshooting Direct Serial Connections
A primary subject matter of your CCNA and CCNP CIT exams might be connecting Cisco routers immediately through their Serial interfaces, and though the configuration is easy, there are some important information and clearly show instructions you will need to know in an effort to 인스타 팔로워 구매 move the exams and configure this efficiently in output and home lab networks. Permit’s Examine a sample configuration.
Connecting Cisco routers directly by using their Serial interfaces is effective really well as soon as you get it running – and having such a connection up and operating is easy plenty of. You need to use clearly show controller serial x to learn which endpoint is acting as the DCE, and it’s the DCE that has to be configured Together with the clockrate command.
R3#show controller serial 1
High definition unit 1, idb = 0x11B4DC, driver structure at 0x121868
buffer dimensions 1524 HD device 1, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip tackle 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 interesting consequences regarding the Actual physical and logical point out of your interfaces. Enable’s take out the clockrate from R3 and find out what occurs.
R3(config)#int s1
R3(config-if)#no clockrate 56000
R3(config-if)#
eighteen:02:19: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, changed point out to down
The line protocol doesn’t fall right away, nevertheless it does drop. Allow’s run show interface serial1 to check the Actual physical and logical interface states.
R3#clearly show int https://www.washingtonpost.com/newssearch/?query=인스타 팔로워 구매 serial1
Serial1 is up, line protocol is down
Physically, the interface is fine, And so the Bodily interface is up. It’s only the sensible Element of the interface – the line protocol – that may be down. It’s exactly the same circumstance on R1.
R1#clearly show inter serial1
Even though a router misconfiguration would be the probably reason for a serial relationship difficulty, that’s not the only reason for clocking troubles. Cisco’s Site documentation mentions CSU/DSU misconfiguration, out-of-spec cables, undesirable patch panel connections, and connecting too many cables with each other as other factors for clocking challenges. Nevertheless, the number 1 reason behind clocking troubles in my experience is simply forgetting to configure the clockrate command!