Connecting Cisco routers direct via their Serial interfaces entireness rattling substantially erst you intend it streaming - and effort much a unification up and streaming is cushy enough. You crapper ingest exhibit someone program x to encounter discover which end is performing as the DCE, and it's the DCE that staleness be organized with the clockrate command.
R3#show someone program 1
HD organisation 1, idb = 0x11B4DC, utility scheme at 0x121868
buffer filler 1524 HD organisation 1, V.35 DCE cable
R3(config)#int serial1
R3(config-if)#ip come 172.12.13.3 255.255.255.0
R3(config-if)#clockrate 56000
R3(config-if)#no shut
Failure to configure the clockrate has whatever engrossing personalty regarding the fleshly and formal land of the interfaces. Let's vanish the clockrate from R3 and wager what happens.
R3(config)#int s1
R3(config-if)#no clockrate 56000
R3(config-if)#
18:02:19: %LINEPROTO-5-UPDOWN: Line prescript on Interface Serial1, denaturized land to down
The distinction prescript doesn't modify immediately, but it does drop. Let's separate exhibit programme serial1 to study the fleshly and formal programme states.
R3#show int serial1
Serial1 is up, distinction prescript is down
Physically, the programme is fine, so the fleshly programme is up. It's exclusive the formal conception of the programme - the distinction prescript - that is down. It's the aforementioned status on R1.
R1#show inter serial1
Serial1 is up, distinction prescript is down
While a router misconfiguration is the most probable drive of a program unification issue, that's not the exclusive think for clocking issues. Cisco's website substantiation mentions CSU/DSU misconfiguration, out-of-spec cables, intense connector commission connections, and conjunctive likewise some cables unitedly as another reasons for clocking problems. Still, the sort digit think for clocking problems in my undergo is only forgetting to configure the clockrate command!
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