Cisco CCNA / CCNP Certification Examination: Troubleshooting Direct Serial Connections
A chief topic within your CCNA and http://www.thefreedictionary.com/토토사이트 CCNP CIT exams is going to be connecting Cisco routers specifically by means of their Serial interfaces, and when the configuration is straightforward, there are some critical details and demonstrate instructions you must know in an effort to go the exams and configure this successfully in creation and home lab networks. Enable’s Check out a sample configuration.
Connecting Cisco routers immediately by way of their Serial interfaces works very well as soon as you get it running – and finding such a relationship up and working is a snap plenty of. You can utilize demonstrate controller serial x to determine which endpoint is acting since 안전놀이터 the DCE, and it’s the DCE that should be configured with the clockrate command.
R3#show controller serial 1
HD device one, idb = 0x11B4DC, driver construction at 0x121868
buffer size 1524 High definition device one, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip deal with 172.12.13.three 255.255.255.0
R3(config-if)#clockrate 56000
R3(config-if)#no shut
Failure to configure the clockrate has some attention-grabbing results concerning the Bodily and logical point out with the interfaces. Allow’s remove the clockrate from R3 and find out what transpires.
R3(config)#int s1
R3(config-if)#no clockrate 56000
R3(config-if)#
eighteen:02:19: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, transformed point out to down
The line protocol doesn’t drop promptly, however it does drop. Enable’s operate display interface serial1 to check the Bodily and logical interface states.
R3#demonstrate int serial1
Serial1 is up, line protocol is down
Physically, the interface is ok, Therefore the Actual physical interface is up. It’s only the reasonable part of the interface – the line protocol – that's down. It’s the exact same circumstance on R1.
R1#display inter serial1
Whilst a router misconfiguration may be the more than likely reason for a serial connection difficulty, that’s not the only real cause of clocking concerns. Cisco’s Web-site documentation mentions CSU/DSU misconfiguration, out-of-spec cables, undesirable patch panel connections, and connecting a lot of cables collectively as other good reasons for clocking challenges. However, the number one reason for clocking issues in my encounter is simply forgetting to configure the clockrate command!