Cisco CCNA/ CCNP Accreditation Test: Fixing Straight Serial Links
A prime subject of your CCNA and also CCNP CIT examinations will certainly be attaching Cisco routers straight by means of their Serial user interfaces, as well as while the arrangement is simple, there are some essential information as well as reveal commands you should recognize in order to pass the examinations as well as configure this effectively in manufacturing as well as house laboratory networks. Allow’s have a look at an example setup.
Linking Cisco routers straight by means of their Serial user interfaces functions truly well once you obtain it running – as well as obtaining such a link up as well as running is simple sufficient. You can utilize program controller serial x to learn which endpoint is functioning as the DCE, as well as it’s the DCE that should be set up with the clockrate command.
R3 #show controller serial 1
HD device 1, idb = 0x11B4DC, chauffeur framework at 0x121868
barrier dimension 1524 HD device 1, V. 35 DCE wire
R3( config) #int serial1
R3( config-if) #ip address 172.12.13.3 255.255.255.0
R3( config-if) #clockrate 56000
R3( config-if) #no closed
Failing to set up the clockrate has some intriguing impacts concerning the rational and also physical state of the user interfaces. Allow’s get rid of the clockrate from R3 as well as see what occurs.
R3( config) #int s1
R3( config-if) #no clockrate 56000
R3( config-if) #.
18:02:19: %LINEPROTO-5-UPDOWN: Line method on Interface Serial1, altered state to down.
While a router misconfiguration is one of the most likely source of a serial link concern, that’s not the only factor for clocking problems. Cisco’s site paperwork discusses CSU/DSU misconfiguration, out-of-spec wires, poor spot panel links, and also attaching a lot of wires with each other as various other factors for clocking troubles. Still, the primary factor for clocking troubles in my experience is just neglecting to set up the clockrate command!
Serial1 is up, line method is down.
Literally, the user interface is great, so the physical user interface is up. It’s just the sensible component of the user interface – the line method – that is down. While a router misconfiguration is the most likely reason of a serial link problem, that’s not the only factor for clocking concerns. Cisco’s site documents states CSU/DSU misconfiguration, out-of-spec cable televisions, poor spot panel links, as well as linking as well numerous cords with each other as various other factors for clocking troubles. Still, the number one factor for clocking troubles in my experience is just neglecting to set up the clockrate command!
R1 #show inter serial1.
Serial1 is up, line procedure is down.
Literally, the user interface is great, so the physical user interface is up. It’s just the rational component of the user interface – the line method – that is down. It’s the exact same circumstance on R1.
R3 #show int serial1.
The line procedure does not go down right away, however it does go down. Allow’s run program user interface serial1 to contrast the sensible and also physical user interface states.
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