Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations Chriss Miller on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!

Serial is up, line protocol is down

Status
Not open for further replies.

sohtnax

IS-IT--Management
Apr 24, 2003
130
US
In the middle of the day I lost internet access, turned out there is a problem on the Serial Interface on my 2620 router, which connects to our ISP using Frame Relay. It showed that Serial is up, line protocol is down.

I tried to shutdown the port and then do a no sh but it stay up for only a few seconds before it drops again. I tried rebooting the router and called my ISP who said my circuit was fine, and I could see that they were in it because the test lights were changing back and forth. I also conferenced in Cisco with my ISP, and they too were stumped. The Cisco tech and ISP tech compared all their stats, encapsulation methods, etc. and everything matched up as it should. I have changed all my cables, and even replaced the CSU/DSU card with a new one. I am pretty sure that it is not an issue with my ISP, simply because I took all the existing cables and plugged them into a 2620 backup router, which is configured identical to the router which went bad, and it is working. I also tried restoring a backup from December to the router, but it still won't work.

You can see in the PVC stats, which are diaplayed below that under Local it shows 1 Deleted, which I believe is part of my problem.

Here is the frame-relay and interface stats from my bad router:


PVC Statistics for interface Serial0/0 (Frame Relay DTE)

Active Inactive Deleted Static
Local 0 0 1 0
Switched 0 0 0 0
Unused 0 0 0 0

DLCI = 210, DLCI USAGE = LOCAL, PVC STATUS = DELETED, INTERFACE = Serial0/0

input pkts 0 output pkts 108 in bytes 0
out bytes 9066 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 3 out bcast bytes 1824
pvc create time 00:07:23, last time pvc status changed 00:01:18



sh int s0/0
Serial0/0 is up, line protocol is down
Hardware is PQUICC with Fractional T1 CSU/DSU
Description: Router1
Internet address is 21X.9X.2XX.2XX/30
MTU 1500 bytes, BW 1536 Kbit, DLY 20000 usec,
reliability 250/255, txload 1/255, rxload 1/255
Encapsulation FRAME-RELAY IETF, loopback not set
Keepalive set (10 sec)
LMI enq sent 97, LMI stat recvd 0, 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
Broadcast queue 0/64, broadcasts sent/dropped 3/0, interface broadcasts 3
Last input never, output 00:00:03, output hang never
Last clearing of "show interface" counters 00:21:25
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 43 giants, 0 throttles
1613 input errors, 12 CRC, 247 frame, 0 overrun, 0 ignored, 1354 abort
203 packets output, 10396 bytes, 0 underruns
0 output errors, 0 collisions, 39 interface resets
0 output buffer failures, 0 output buffers swapped out
6 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up



Here is the same info from the router I am currently using, which is working right now:

sh frame-relay

PVC Statistics for interface Serial0/0 (Frame Relay DTE)

Active Inactive Deleted Static
Local 1 0 0 0
Switched 0 0 0 0
Unused 0 0 0 0

DLCI = 210, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0

input pkts 1057 output pkts 1085 in bytes 87797
out bytes 80944 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 0 out bcast bytes 0
pvc create time 00:16:12, last time pvc status changed 00:00:3


sh int s0/0
Serial0/0 is up, line protocol is up
Hardware is PQUICC with Fractional T1 CSU/DSU
Description: Router2
Internet address is 21X.9X.2XX.2XX/30
MTU 1500 bytes, BW 1536 Kbit, 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 20, LMI stat recvd 19, LMI upd recvd 0, DTE LMI up
LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0
LMI DLCI 0 LMI type is ANSI Annex D frame relay DTE
Broadcast queue 0/64, broadcasts sent/dropped 0/0, interface broadcasts 0
Last input 00:00:05, output 00:00:05, output hang never
Last clearing of "show interface" counters 00:17:31
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 2000 bits/sec, 3 packets/sec
5 minute output rate 1000 bits/sec, 3 packets/sec
1569 packets input, 122780 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
1688 input errors, 445 CRC, 1179 frame, 0 overrun, 0 ignored, 63 abort
1566 packets output, 107033 bytes, 0 underruns
0 output errors, 0 collisions, 26 interface resets
0 output buffer failures, 0 output buffers swapped out
2 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up


Any help or suggestions is much appreciated!!!
 
Whenever the output of "show frame pvc" displays DELETED, it means your PVC to provider's Frame Relay switch is not working. However from looking into outputs of your serial interfaces, I can see the encapsulation and LMI is set correctly. Do your routers both run the same IOS? Maybe this is just a rare bug.

Also maybe sending the output of "debug frame lmi" from affected router to Cisco TAC will help you. Or post it here maybe me or somebody else on this forum can help you further.

Hope this helps:)

Peter Mesjar
CCNP, A+ certified
pmesjar@centrum.sk

"The only true wisdom is in knowing you know nothing.
 
One more point - what did you do last time the affected router functioned correctly?

Peter Mesjar
CCNP, A+ certified
pmesjar@centrum.sk

"The only true wisdom is in knowing you know nothing.
 
First router shows "LMI enq sent 97, LMI stat recvd 0" whereas the second router output shows "LMI enq sent 20, LMI stat recvd 19".

In other words, your non-working router is not seeing LMI updates from your ISP. On the face of it this seems to be the problem, yet the two routers seem to be set the same - confusing!

Could you post the running-config?
 
Thanks to everyone for your help, however the problem was the slot in which the CSU/DSU card was in had gone bad. I moevd the card to another open slot and everything has been working fine!

Thanks again for all your help!
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top