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Flapping Serial Connections

Today I decided to run though some labs, since the weather was crappy. The two router labs went well, but the three router labs started to give me some trouble.

I started getting the following message:

*Mar  1 00:16:35.203: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to down

Which a few seconds later would be followed by this message:

*Mar  1 00:16:35.203: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to up

I went through everything I could think of, and even cleared each routers config file multiple times. Baffled, and a bit frustrated, I walked away for a bit. When I came back, it dawned on me that I never checked the cables I was using (I had swamped them, but I did not check them).

Sure enough, a few pins pins on the serial cables that connected to my third 2513 router were bent. I examined the serial ports on that router and discovered that there were pins jammed in the connector. I can honestly say this was not caused by me, since I only have one set of Serial cables, and all of the pins on those were intact (but bent at this point).

So my problems are solved, for now. I will attempt to remove the pins form the router, but if that fails it may get replaced with another 2500 or more likely a 2600XM router.

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