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New Member

2500 weirdness

I have recently had a problem with some 2500 routers. I was connecting to a 7200 via a 2mbs link connected to serial0. When connected the router would show up, up at the 2500 end but up down at the 7200 end. I moved the config and the cable to serial1 and it worked. The same thing happened a few months ago causing me to replace the router. Is there some difference between S0 and S1 that I am not aware of??? Thanks.

New Member

Re: 2500 weirdness

Are you sure the Layer 2 encapsulation is the same at both ends of the WAN CKT (HDLC or PPP)? For troubleshooting, please refer to Table 15-1 ("Serial Lines: show interfaces serial Status Line Conditions") in "Troubleshooting Serial Line Problems" on:

New Member

Re: 2500 weirdness

thanks for your reply. I am positive that both ends are use the default encapsualation HDLC.


Re: 2500 weirdness

Have you tried connecting the serial 0 of the 2500 to another router?

If the serial 0 of the 2500 didn't worked at all, it is probably a

hardware problem.

Here's a list of possible problems:

1. Local or remote router is misconfigured

2. Keepalives are not being sent by remote router

3. Leased-line or other carrier service problem-Noisy line, or misconfigured or failed switch

4. Timing problem on cable (SCTE [5] not set on CSU/DSU)

5. Failed local or remote CSU/DSU

6. Router hardware failure (local or remote)

Here's a the link for troubleshooting:


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