You get up/up when looping HDLC back to itself. Up/down when looping PPP back to itself. Your experience is correct.
Is there someone at the remote end to look at that router? If not can you establish out-of-band connection via a modem? Verify that configs match. Look for loopbacks. Make up a hard-wired loopback plug and jack for each end. You want to test from the demark point and from the wire that connects into the CSU/DSU. Most likely the telco tests to the demark point - a device called a "smartjack" that can be remotely looped. Several things can go wrong. (1) There is a problem in the smartjack beyond where the loopback is applied. (2) They forgot to remove the remote loopback. (3) They re-groomed the circuit and are testing to the wrong smartjack. It really helps to have someone physically at each end. Just as you tested locally with a loopback button - see if you can test locally with a loopback plug. (I'm assuming you have an RJ-48 / RJ-45 style telephone network connection.) Remove the telco facing wire and plug in your loopback plug. With your router interface set to HDLC (temporarily for testing) you should see up/up (looped). Put the wire back in. Go to the end of the wire at the demark. Remove the wire and put a loopback jack on it. Again you should see up/up (looped). If not, the wire is suspect. Replace the wire. See if the person at the far end can (a) replicate what you did for their end. (b) Then give you a hard loopback with their loopback plug in the demark. If you can't see that loop be applied and removed then the telco circuit is suspect. At this point you can ping your own address. Try pings with different bit patterns - use many large packets - extended ping allows this. There is a good paper on CCO with the patterns and what they detect. All zeros, all ones (0xFFFF), alternating ones and zeros (0xAAAA). Verify the settings on the CSU/DSUs. Good luck. > -----Original Message----- > From: James Gosnold [mailto:[EMAIL PROTECTED] > Sent: Tuesday, May 27, 2003 11:42 AM > To: [EMAIL PROTECTED] > Subject: Re: Leased line/1721 problem [7:69573] > > > Dave, > > If I press the 'loopback' button on the DSU itself then the router > recognises this and shows Interface up, line protocol down (looped). > > Strange thing I noticed is that if I chance encapsulation to > HDLC and press > the local loopback button on the DSU I get Interface up, line > protocol up > (looped). > > > MADMAN wrote: > > > > I have seen moe than once a faulty WIC-1DSU-T1 cause similiar > > problems. Have you tried doing your own hardwire loop? > > > > Dave Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=69601&t=69573 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
