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Excessive Carrier Transitions

Hi All

When I do a show interface s0/1 on my 2620 router, I get the following:

Serial0/1 is down, line protocol is down

Hardware is PowerQUICC Serial

Internet address is

MTU 1500 bytes, BW 192 Kbit, DLY 20000 usec,

reliability 255/255, txload 2/255, rxload 17/255

Encapsulation HDLC, loopback not set

Keepalive set (10 sec)

Last input 00:00:05, output 00:00:19, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 1913

Queueing strategy: priority-list 1

Output queue (queue priority: size/max/drops):

high: 0/20/0, medium: 0/40/0, normal: 0/60/0, low: 0/80/0

5 minute input rate 13000 bits/sec, 5 packets/sec

5 minute output rate 2000 bits/sec, 2 packets/sec

416705 packets input, 303038720 bytes, 0 no buffer

Received 6014 broadcasts, 0 runts, 0 giants, 0 throttles

2854 input errors, 7 CRC, 64 frame, 0 overrun, 0 ignored, 0 abort

355821 packets output, 56929325 bytes, 0 underruns

0 output errors, 0 collisions, 606 interface resets

0 output buffer failures, 0 output buffers swapped out

293839 carrier transitions

DCD=down DSR=up DTR=up RTS=up CTS=up

As you can see, in the past 19 hours, I have had 293839 carrier transitions on this interface. I have had my service provider test the line, and they maintain that the line test fine - although the first time it was reported, there was a misconfiguration on their NTU...

Anything else that I should have a look at?



Re: Excessive Carrier Transitions

cabling perhaps, you also have some crc, input and frame errors.

is this a poin to point (like a t-1)?

have the carrier run a loopback test to the dsu/csu.

from the demarc, how long (complicated) is the cabling to the dsu/csu ?