09-09-2013 05:26 PM - edited 03-04-2019 08:59 PM
I would like to know how to test a loopback when the telco has given me the loop? Is there any configuration needed on the router to see the loopback coming from the telco? thanks
This is the serial interface
ROUTER#sh int s0/1/0
Serial0/1/0 is up, line protocol is down
Hardware is WIC MBRD Serial
Description: *** LINK TO INNOVE: IC-AEZ-7992 ***
Internet address is 10.63.205.54/30
MTU 1500 bytes, BW 256 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation FRAME-RELAY IETF, loopback not set
Keepalive set (10 sec)
LMI enq sent 64845, LMI stat recvd 62572, LMI upd recvd 0, DTE LMI down
LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0
LMI DLCI 0 LMI type is ANSI Annex D frame relay DTE segmentation inactive
FR SVC disabled, LAPF state down
Broadcast queue 0/64, broadcasts sent/dropped 12135/0, interface broadcasts 11
271
Last input 06:19:18, output 00:00:08, output hang never
Last clearing of "show interface" counters 1w0d
Input queue: 0/75/0/98 (size/max/drops/flushes); Total output drops: 4039111
Queueing strategy: weighted fair
Output queue: 0/1000/64/4039111 (size/max total/threshold/drops)
Conversations 0/21/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 192 kilobits/sec
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
2067246 packets input, 1100838086 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
1417 runts, 0 giants, 0 throttles
4531 input errors, 323 CRC, 0 frame, 0 overrun, 0 ignored, 2791 abort
1878089 packets output, 236373863 bytes, 0 underruns
0 output errors, 0 collisions, 751 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
8 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
09-09-2013 05:43 PM
Serial0/1/0 is up, line protocol is down
Your telco didn't have the loop set.
If there was a loop, it would be Layer 1 is DOWN but protocol would be UP.
09-09-2013 05:50 PM
hi leo, so which means i don't see the loop. what will i do to see the loop? also is there configuration needed?
09-09-2013 06:00 PM
Loopback Tests for T1/56K Lines
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09-09-2013 06:28 PM
the serial interface is FRAME-RELAY IETF encapsulation. the link is about hdlc.
09-09-2013 06:32 PM
It doesn't matter. As long as you can run the "diagnostics loopback" command on the interface level.
Make sure you do not do this command on the remote end. Always do this on the local-end router.
09-09-2013 06:40 PM
is this the command that could see loopback coming from telco?
Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#controller t1 0 Router(config-controller)#no pri-group timeslots 1-24 Router(config-controller)#channel-group 0 timeslots 1-24 speed 64 !--- This automatically creates a single Serial0:0 interface. Router(config-controller)#loopback local !--- The loopback local command above is only necessary for software loopbacks. Router(config-controller)#exit Router(config)#interface serial 0:0 Router(config-if)#encapsulation hdlc
09-09-2013 06:48 PM
Should be. Never tried the loopback commands on a router.
Have done loopback tests on Nortel Passports/DPN 100. Even did them with PLDT.
09-09-2013 06:51 PM
i've never tried seeing loopback from the router also. i think it shows only in the serial interface status
09-09-2013 10:24 PM
hi,
better ask telco for a loop instead of the reverse. you should see up/up (looped) on the show interface serial command output.
ask telco from which node they're giving the loop from, then ping the same IP on the router, and check for errors or drops.
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