Cisco CCNA / CCNP Certification Test: Troubleshooting Direct Serial Connections
A chief topic of the CCNA and CCNP CIT 인스타그램 팔로워 늘리기 exams will likely be connecting Cisco routers right through their Serial interfaces, and while the configuration is straightforward, there are many essential aspects http://www.bbc.co.uk/search?q=인스타 팔로워 구매 and exhibit commands you must know so as to pass the examinations and configure this successfully in manufacturing and home lab networks. Allow’s Have a look at a sample configuration.
Connecting Cisco routers right by means of their Serial interfaces will work really well as soon as you get it running – and acquiring such a relationship up and running is not hard plenty of. You should use demonstrate controller serial x to discover which endpoint is acting as being the DCE, and it’s the DCE that needs to be configured With all the clockrate command.
R3#exhibit controller serial one
HD unit 1, idb = 0x11B4DC, driver composition at 0x121868
buffer sizing 1524 High definition unit 1, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip address 172.12.thirteen.3 255.255.255.0
R3(config-if)#clockrate 56000
R3(config-if)#no shut
Failure to configure the clockrate has some exciting consequences regarding the Actual physical and reasonable point out of your interfaces. Permit’s eliminate the clockrate from R3 and find out what comes about.
R3(config)#int s1
R3(config-if)#no clockrate 56000
R3(config-if)#
eighteen:02:19: %LINEPROTO-five-UPDOWN: Line protocol on Interface Serial1, improved state to down
The road protocol doesn’t drop right away, nevertheless it does drop. Permit’s operate present interface serial1 to check the physical and logical interface states.
R3#demonstrate int serial1
Serial1 is up, line protocol is down
Bodily, the interface is okay, so the Actual physical interface is up. It’s just the rational Section of the interface – the road protocol – that is certainly down. It’s the exact same circumstance on R1.
R1#show inter serial1
While a router misconfiguration may be the most likely reason for a serial link issue, that’s not the one cause of clocking challenges. Cisco’s Site documentation mentions CSU/DSU misconfiguration, out-of-spec cables, poor patch panel connections, and connecting a lot of cables jointly as other explanations for clocking troubles. Even now, the number 1 basis for clocking complications in my expertise is just forgetting to configure the clockrate command!