Cisco CCNA / CCNP Certification Test: Troubleshooting Direct Serial Connections
A primary subject matter 토토사이트 of the CCNA and CCNP CIT examinations is going to be connecting Cisco routers straight by using their Serial interfaces, and while the configuration is simple, there are numerous vital facts and show commands you have to know in order to move the exams and configure this effectively in manufacturing and residential lab networks. Enable’s Consider a sample configuration.
Connecting Cisco routers immediately via their Serial interfaces functions very well as you get it functioning – and getting such a link up and working is straightforward more than enough. You should use display controller serial x to learn which endpoint is acting given that the DCE, and it’s the DCE that should be configured Along with the clockrate command.
R3#exhibit controller serial 1
HD device one, idb = 0x11B4DC, driver framework at 0x121868
buffer size 1524 HD unit one, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip handle 172.twelve.thirteen.three 255.255.255.0
R3(config-if)#clockrate 56000
R3(config-if)#no shut
Failure to https://en.search.wordpress.com/?src=organic&q=토토사이트 configure the clockrate has some attention-grabbing consequences regarding the Bodily and reasonable point out of the interfaces. Permit’s take away 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, but it does drop. Let’s operate show interface serial1 to compare the Bodily and sensible interface states.
R3#clearly show int serial1
Serial1 is up, line protocol is down
Bodily, the interface is fine, Hence the Bodily interface is up. It’s just the sensible Portion of the interface – the line protocol – that's down. It’s exactly the same problem on R1.
R1#display inter serial1
Although a router misconfiguration would be the probably reason for a serial relationship situation, that’s not the only reason for clocking challenges. Cisco’s Web site documentation mentions CSU/DSU misconfiguration, out-of-spec cables, lousy patch panel connections, and connecting a lot of cables collectively as other causes for clocking difficulties. Nonetheless, the number one reason behind clocking problems in my practical experience is actually forgetting to configure the clockrate command!