Re: Protocoll problems, may be. Need Help!!! - Page 2

c-henrich · ‎03-24-2003

I have 2 Cisco 2600 which are connected via serial (Hardware: PowerQuicc) Interfaces. They have a DSU-Modem with a t1 Connection. I testet Hardware-Loops on both sites going over the hole line and all of them worked fine. Both interfaces are sending HDLC packetes, but thy doesn't get any Input. So I doesn't know where the Problems are! the Line is testet without errors, and a protokoll is not running.

May be some of you can help me......

deilert · ‎03-26-2003

What about when the provider gave you a loop from the same place in the other direction ? What happened to that interface ? Can you past in a sh interface from both ends ?

tjin · ‎03-26-2003

Try using HDLC as encapsulation. I had the same problem once, the moment I changed them to HDLC, the link came up.

c-henrich · ‎03-26-2003

Actual i'm using HDLC but i also tried PPP both aren't working!

c-henrich · ‎03-26-2003

My Provider gave me Loops in ervery direction and at both ends, all of them were fine!

Actual i'm switched over to an old cicuit so i have no "sh int" at the moment.

But may be this helps:

the log shows two lines wich confused me

*Mar 2 02:45:58.788: Serial0/0: attempting to restart

*Mar 2 02:45:58.788: PowerQUICC(0/0): DCD is up.

deilert · ‎03-27-2003

Have the person who has access to the CSU give you a DTE loop . This loops the DSU back towards the router . When your interface goes up up looped, ping yourself.

c-henrich · ‎03-27-2003

i had done this and the statisiks showed no errors or crc's

deilert · ‎03-27-2003

Can you past in a sh interface and the config of the serial interfaces from both sides .

michael-faust · ‎03-31-2003

OK You are using HDLC. Are you using keepalives at both ends? Are the keepalive timers set to the same value? Are the interfaces 'up' and 'up'? Are all of the control leads 'up'? When the answer to all of these questions is "yes", you are ready to test. Also, check to see if the T1 line is reversed at some point (transmit and receive reversal). When a T1 line is reversed, it won't work end to end but will work great to a loop at certain points in the circuit.

Go to one end. Loop the local DSU back toward the router. Is the interface 'up up (looped)'? Good. Release the loopback.

Loop the local CSU back toward the router. Is the interface 'up up (looped)'? Good. Release the loopback.

Remove the T1 line frome the CSU and put in a looping plug. Is the interface 'up up (looped)'? Good. Remove the plug and reinsert the T1 line.

Remove the remote T1 line from the remote CSU and loop the T1 back toward the local end. This step may or may not work depending on the loss on the T1 to that point. Is the local interface 'up up (looped)'? Good. Remove the loopback and reinsert the T1 in the CSU.

Loop the remote CSU back toward the local end. Is the local interface 'up up (looped)'? Good. Release the loopback.

Loop the remote DSU back toward the local end. Is the local interface 'up up (looped)'? Good. Release the loopback.

Repeat all of the tests from the other end. If all of these tests work, you have proven that the line, CSU/DSUs, cabling and routers are good. If they still won't talk to eachother, let me know and I will try to help some more.

Another thing. As with all trouble shooting, keep a log of the tests and the results. If you are still having problems, post the log. Good hunting!!!

alfonsoresendiz · ‎04-25-2003

Hi!

When your SP loops toward you, how are yo assuming the link is OK??

with just #sh int ser, you are not able to see much info.

When loops toward you, put HDLC encaps. and make an extended ping with the packet size of 1500 (kind of ethernet), and use these data patterns:

0X0000

0X4040

OXFFFF

On every loop, clear the counters, and after every ping test, check the serial, it may be present on this case CRCs, interfase resets or something...these data patterns helps you to identyfing clocking issues, electrical problems, jitter, etc..

Please let me know if this tests helped you to find out more info.

Regards

deilert · ‎03-28-2003

You may want to have the config of the CSU's checked to ensure that one of the units is set to provide clock and the other is set to receive clock.

ejaj · ‎03-30-2003

It seems connectivity is present which you have verified by using local and remote loopback test. Moeover serial line and protocol both are up. Now the left possibilty is, not getting Tx and Rx signals at correct pins. Try after Interchage Tx and Rx on serial line. Ensure encapsulation at both side is same- no matter whether PPP or HDLC.

---ejaj

michael-faust · ‎04-01-2003

Sorry - I clicked the wrong spot to reply to you and my reply may have been missed. If you are still seeking help, look at my response above (from 3/31/03). If I can help more, let me know.

c-henrich · ‎04-07-2003

Thank you all for your help, the problem was a wrong confuduration on one DSU.

It's very confusing to me why there is a strange configuration like CRC of and timeslots 1-24.

How ever i'm glad that the line is working now!!