Cisco CCNA / CCNP Certification Examination: Troubleshooting Direct Serial Connections
A first-rate subject matter of your CCNA and CCNP CIT examinations might be connecting Cisco routers right by way of their Serial interfaces, and whilst the configuration is easy, there are numerous critical specifics and clearly show instructions you will need to know in an effort to go the examinations and configure this properly in generation and residential lab networks. Let’s Have a look at a sample configuration.
Connecting Cisco routers straight by way of their Serial interfaces operates very well as you 인스타 좋아요 늘리기 get it managing – and obtaining this kind of link up and working is simple sufficient. You can use clearly show controller serial x to see which endpoint is acting since the DCE, and it’s the DCE that has to be configured Using the clockrate command.
R3#demonstrate controller serial one
High definition unit one, idb = 0x11B4DC, driver composition at 0x121868
buffer dimensions 1524 High definition device one, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip tackle 172.twelve.13.3 255.255.255.0
R3(config-if)#clockrate 56000
R3(config-if)#no shut
Failure to configure the clockrate has some exciting consequences regarding the physical and logical condition with the interfaces. Permit’s take out the clockrate from R3 and see what comes about.
R3(config)#int s1
R3(config-if)#no clockrate 56000
R3(config-if)#
eighteen:02:19: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, adjusted condition to down
The line protocol doesn’t drop instantly, however it does fall. Allow’s operate demonstrate interface serial1 to match the Bodily and reasonable interface states.
R3#show int serial1
Serial1 is up, line protocol is down
Bodily, the interface is ok, And so the Actual physical interface is up. It’s just the sensible part of the interface – the line protocol – that may be down. It’s the identical situation on R1.
R1#present inter serial1
Though a router misconfiguration may be the most certainly explanation for a serial connection concern, that’s not the sole basis for clocking issues. Cisco’s Web site documentation mentions CSU/DSU misconfiguration, out-of-spec http://www.thefreedictionary.com/인스타 팔로워 구매 cables, negative patch panel connections, and connecting a lot of cables collectively as other causes for clocking complications. However, the number 1 cause of clocking difficulties in my working experience is just forgetting to configure the clockrate command!