10-29-2006 10:12 PM - edited 03-03-2019 02:30 PM
Dear Friends,
I have a numbers of serial links. I am using 3700,2600 and 1941 series router.Recently I am experienced a trouble in my 3700 and 1941 series router. Problem is as belows:
The seral link goes off . It shows that the serial is up but the line protocol is down.The e1 controller is alwas up.For testing link, I set the local loopback and found that teh link is still down. After some time , the link gets up autometically. Please see the sh interface result before and after loop back. Please help as soon as possible and feel free to querey.
Yours,
bikash
=========================================
Serial0/2:0 is up, line protocol is down
Hardware is GT96K Serial
Description: XXXX LINK
Internet address is 172.16.254.50/30
MTU 1500 bytes, BW 1984 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Listen
Closed: CDPCP, PPPMUXCP, IPCP, loopback not set
Last input 00:00:08, output 00:00:06, output hang never
Last clearing of "show interface" counters 7w6d
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 51
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
1075084 packets input, 330059814 bytes, 0 no buffer
Received 0 broadcasts, 228 runts, 0 giants, 0 throttles
739213 input errors, 739207 CRC, 149247 frame, 33546 overrun, 0 ignored, 16
3867 abort
4738928 packets output, 219644729 bytes, 0 underruns
0 output errors, 0 collisions, 7454 interface resets
0 output buffer failures, 0 output buffers swapped out
4351 carrier transitions
Timeslot(s) Used:1-31, SCC: 2, Transmitter delay is 0 flags
AAAAAA#conf t
Enter configuration commands, one per line. End with CNTL/Z.
AAAAAA(config)#inter Serial0/2:0
AAAAAA(config-if)#loop
AAAAAA(config-if)#loopback ?
<cr>
AAAAAA(config-if)#loopback
AAAAAA(config-if)#do sh inter Serial0/2:0
Serial0/2:0 is up, line protocol is down
Hardware is GT96K Serial
Description: XXXX LINK
Internet address is 172.16.254.50/30
MTU 1500 bytes, BW 1984 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Listen
Closed: CDPCP, PPPMUXCP, IPCP, loopback set
Last input 00:00:19, output 00:00:11, output hang never
Last clearing of "show interface" counters 7w6d
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 51
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
1075095 packets input, 330059968 bytes, 0 no buffer
Received 0 broadcasts, 228 runts, 0 giants, 0 throttles
739221 input errors, 739215 CRC, 149248 frame, 33546 overrun, 0 ignored, 16
3868 abort
4738956 packets output, 219645113 bytes, 0 underruns
0 output errors, 0 collisions, 7458 interface resets
0 output buffer failures, 0 output buffers swapped out
4351 carrier transitions
Timeslot(s) Used:1-31, SCC: 2, Transmitter delay is 0 flags
10-29-2006 10:44 PM
Hello,
looking at your output, there seems to be a physical problem with either your cabling, the modem attached to your serial interface, or the interface(s) themselves. The high number of input errors, CRC, frame, and overrun errors point to such a phyiscal problem. If possible, try and replace the cable, switch to another interface, or have your ISP run a loopback test to the modem (which they should be able to do).
HTH,
GNT
10-30-2006 01:55 AM
Dear GNT,
I have no modem.Microwave transmission link exists between the two E1 card of two routers. Four diffrenet routers are showing these type of phenomena . Interesting thing is that the trouble is corrected by itself after some time.
10-31-2006 01:11 AM
Hi Bikash
From my personal experience with RF/Microwave links better check the reliability of the link with the help of the vendor whoever is maintaining the link.
Your provider may have the required tools to check the reliability and set the same on error free frequency too if he finds some drops or interference with the current frequency.
regds
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