whats the problem

[cisco]

Hi ,

I am getting several errors on serial interface.Please help

Serial1/0 is up, line protocol is down (looped)

Hardware is DSXPNM Serial

Internet address is 2.6.8.6/30

MTU 1500 bytes, BW 44210 Kbit, DLY 200 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation PPP, LCP Listen, crc 32, loopback not set

Keepalive set (5 sec)

Last input 00:00:12, output 00:00:12, output hang never

Last clearing of "show interface" counters 00:08:58

Input queue: 0/4096/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/4096 (size/max)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

220 packets input, 3080 bytes, 0 no buffer

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

9 input errors, 9 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

220 packets output, 3080 bytes, 0 underruns

0 output errors, 0 collisions, 11 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

DSU mode 0, bandwidth 44210, real bandwidth 44210, scramble 1

regards

Neo

[vijayasankar]

Hi,

Currently the link is in looped state.

Have you introduced any loop to check the Leased line?

-VJ

[cisco]

yes its in looped state, i am currently testing the link.what i am more concern is abt the CRC errors and Interface resets ??

regards

Neo

[vijayasankar]

Hi,

For CRC and interface errors, you need to check the layer 1 completely end to end.

Check the physical layer connectivity throughly.

-VJ

[cisco]

Interface resets and CRC errors are inter related ?

regards

Neo

[vijayasankar]

Not exactly, but Both errors indicates a bad physical layer connectivity.

Interface reset counter indicates the number of times the interface has gone down completely and came back.

-VJ

[minumathur]

Hi.

I think, when you use encapulsation PPP, it wil not give you "Loop" status on router's serial interface , as you past in post.

I think you need to check physical layer

1) check physical cable

2) check encapsulation both side

3) check controller status, any alram received ?

I think this will help you ..

-Minu

[vijayasankar]

Hi Minu,

Encapsulation has no relationship with detecting loop in the link.

I think what you meant is, when we have HDLC encap on the serial link and introduce a loop in the network, the serial link status will come as "serial up/line protocol up"

In this stage, you can ping the serial interface ip address, which will travel down the physical layer path gets looped and come back. This is generally used to test the stability of the link.

Whereas when you have the encap as ppp and loop the link, the line protocol will not come up.

Hope this clarifies.

-VJ

[rameshwarhiwale]

do one thing just reboot the modem then check the connectivity from mux, it will becouse of wic or lese line issue & but still this interface reset comes when the errors are too much