Weird Clock Rate Issue...

Situation… I have a 2610 with a NM-4A/S, I have each serial interface with the DCE plugged into each slot. I have the DTE going to the other serial interfaces of the other routers. I configured the clock rate on the DCE and setup each router’s serial interface with an ip address and etc…

I was not able to get the line protocol to come up! Of course I ran a no shut on all interfaces and the interface would come up, but the line protocol would be down. After pondering, I decided to switch the cables and run each router as the clock rate provider back to the 2610 with the NM-4A/S. Without changing a single configuration other than setting the clock rates on the other routers’ serial interface (once cables were switched), I was able to immediately ping each interface on the other end of the DTE/DCE cable.

I’m curious as to why this would happen? If I setup the 2610 w/ the NM-4A/S as a frame switch, I have to provide the clock rate from each interface of the 2610, but if it is setup as a “hub” in a hub and spoke config, it cannot provide the clock rate to the other routers? Is this true? Any insight would be greatly appreciated.

~Peanut Head

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Comments

Mishra

Are these all serial connections? You are saying switching cables and it's throwing me off.

This will bump your thread at least.

mikej412

Did you do a show controller serial $/$ command?

Is the show controller command showing the ends matching the cable marking? Maybe your cables are labeled incorrectly and wired "backwards."

peanutnoggin

Mishra wrote:

Are these all serial connections? You are saying switching cables and it's throwing me off.

Hi Mishra,

Yes... all of the cables are serial cables. When I was referring to switching cables... I really meant switching cables from one router's serial connection to the other router's serial connection. Hope this helps for clarity!

~Peanut Head

peanutnoggin

mikej412 wrote:

Did you do a show controller serial $/$ command?

Is the show controller command showing the ends matching the cable marking? Maybe your cables are labeled incorrectly and wired "backwards."

Hey Mike,

When I do a sh controllers... the results correspond to what each cable has written on it.

~Peanut Head

APA

DB60 on both sides of the serial connection?? What clock-rate were you using?

peanutnoggin

I used 64000 on each interface. I didn't try to use a different clock rate.

~Peanut Head