I have a cisco 1751 serial i/f conn

[akonwar]

I have a cisco 1751 serial i/f connected to rad asm-20 modem at 64kbps pcm. The other end is channelised e1. There is dataloss on my leased line. The router shows reliablity less than 255. However the "dig" loop
reaches successfully the other end. The total connection setup is:

router---radasm20----64kbps-----radasm20---mylocalexchange(telphoneprovider)
---pcm----(telephoneprovider)remoteexhange---channelised-e1.

The router in/f shows the following.

Hardware is PowerQUICC Serial
Internet address is 10.76.1.118/30
MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec,
reliability 171/255, txload 1/255, rxload 1/255
Encapsulation HDLC, loopback not set
Keepalive set (10 sec)
Last input 02:45:36, output 02:45:35, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 39
Queueing strategy: weighted fair
Output queue: 0/1000/64/38 (size/max total/threshold/drops)
Conversations 0/9/32 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 96 kilobits/sec
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
35775 packets input, 6225988 bytes, 0 no buffer
Received 5235 broadcasts, 0 runts, 3 giants, 0 throttles
8724374 input errors, 5315962 CRC, 3319903 frame, 0 overrun, 0 ignored, 439
1 abort
64486 packets output, 5984797 bytes, 0 underruns
0 output errors, 0 collisions, 398 interface resets
0 output buffer failures, 0 output buffers swapped out
235698 carrier transitions
DCD=up DSR=up DTR=down RTS=down CTS=down

Sometimes the error comes on router "excessive modem control changes". Whats that? I am running ospf on my router leased line which become down every 10-15 mins. What can be the problem and how to troubleshoot.

 

[cull]

8724374 input errors, 5315962 CRC, 3319903 frame, 0 overrun, 0 ignored, 439 1 abort

there's your problem. you have a borked cable, transceiver or some other physical problem, apparently. i'm not overly familiar with the smaller cisco devices, but if you've checked all the obvious stuff (loose connectors, frayed wire, etc etc) try swapping out the interface, if it's modular. your poor router is cratering doing retransmits and such, it seems...