Cisco CCNA / CCNP Certification Exam: Troubleshooting Direct Serial Connections
A first-rate subject of one's CCNA and CCNP CIT tests might be connecting Cisco routers instantly by means of their Serial interfaces, and though the configuration is easy, there are several essential information and clearly show commands you will need to know so as to go the tests and configure this correctly in creation and home lab networks. Permit’s Check out a sample configuration.
Connecting Cisco routers directly by using their Serial interfaces works rather well http://edition.cnn.com/search/?text=토토사이트 when you finally get it managing – and obtaining this type of link up and functioning is simple adequate. You should use display controller serial x to understand which endpoint is acting given that the DCE, and it’s the DCE that should be configured Together with the clockrate 사설사이트 command.
R3#exhibit controller serial one
High definition device 1, idb = 0x11B4DC, driver composition at 0x121868
buffer sizing 1524 High definition device one, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip handle 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 fascinating effects concerning the Actual physical and logical point out from the interfaces. Allow’s clear away 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-five-UPDOWN: Line protocol on Interface Serial1, modified condition to down
The road protocol doesn’t fall immediately, however it does drop. Enable’s operate demonstrate interface serial1 to check the Actual physical and sensible interface states.
R3#clearly show int serial1
Serial1 is up, line protocol is down
Bodily, the interface is okay, And so the Actual physical interface is up. It’s only the logical Component of the interface – the line protocol – that's down. It’s the same scenario on R1.
R1#demonstrate inter serial1
Whilst a router misconfiguration will be the probably explanation for a serial relationship difficulty, that’s not the one reason for clocking concerns. Cisco’s Site documentation mentions CSU/DSU misconfiguration, out-of-spec cables, lousy patch panel connections, and connecting a lot of cables jointly as other factors for clocking troubles. Continue to, the primary basis for clocking troubles in my experience is just forgetting to configure the clockrate command!