07-11-2007 05:39 AM - edited 03-03-2019 05:49 PM
I'm having some trouble w/ a T1 line that I've been troubleshooting. The link is steady (doesn't lose connectivity), but as soon as we start to pass traffic through it the data rate drops exponentially. Its like we're on an old 56k line when transferring files.
We have a cisco router w/ a serial WIC card which connects to an adtran. Then we connect through copper lines (w/ a pair gain on each end) to another building that houses the service provider equipment.
Not sure how to continue troubleshooting this, could the slow datarates be due to the pairgains / copper lines? Or could it be a configuration on the routers?
Any help is always appreciated.
Thanks!
07-11-2007 05:42 AM
Show interface please ?
07-11-2007 06:25 AM
Serial0/0 is up, line protocol is up
Hardware is PowerQUICC Serial
Interface is unnumbered. Using address of FastEthernet0/0
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, reliability 255/255, txload 2/255, rxload 1/255 Encapsulation PPP, LCP Open
Open: IPCP, loopback not set
Keepalive set (10 sec)
Last input 00:00:01, output 00:00:01, output hang never
Last clearing of "show interface" counters
Input queue: 0/75/741/0 (size/max/drops/flushes); Total output drops: 8178
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 4000 bits/sec, 4 packets/sec
5 minute output rate 15000 bits/sec, 3 packets/sec
100172440 packets input, 379597156 bytes, 3 no buffer
Received 0 broadcasts, 1 runts, 7 giants, 0 throttles
542073 input errors, 17165 CRC, 295988 frame, 0 overrun, 0 ignored, 228913 abort
97376318 packets output, 2994254947 bytes, 0 underruns
0 output errors, 0 collisions, 3788 interface resets
0 output buffer failures, 0 output buffers swapped out
252 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
Serial0/0 is up, line protocol is up
Hardware is PowerQUICC Serial
Interface is unnumbered. Using address of FastEthernet0/0
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 6/255
Encapsulation PPP, LCP Open
Open: IPCP, loopback not set
Keepalive set (10 sec)
Last input 00:00:00, output 00:00:00, output hang never Last clearing of "show interface" counters 20:38:14
Input queue: 0/75/212/0 (size/max/drops/flushes); Total output drops: 2581
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 42000 bits/sec, 11 packets/sec
5 minute output rate 12000 bits/sec, 11 packets/sec
4140450 packets input, 919647042 bytes, 0 no buffer
Received 0 broadcasts, 1 runts, 1 giants, 0 throttles
165683 input errors, 7814 CRC, 76389 frame, 0 overrun, 0 ignored, 81477 abort
4307778 packets output, 2715868322 bytes, 0 underruns
0 output errors, 0 collisions, 61 interface resets
0 output buffer failures, 0 output buffers swapped out
31 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
07-11-2007 06:57 AM
You are getting excessive input errors and output drops. Try clearing the counters on both sides and see what the results show then. If the errors continue then you may have a T-1 issue. Do you know what has been provisioned to you by your carrier? Is it a full T-1. Also how are the end point CSU's setup for? Can you do a SHOW CONTROLLER T-1 from both sides to see the layer 1 stats of the line.....
07-11-2007 09:47 AM
Yes, its a full T1, not a fractional.. There are no T1 controllers on the router, it shows none. The router just handles the physical connection, the adtran actually has the line coding, and framing on it..
Its an old setup, but I'm confident that it shouldn't be as slow as it is now.
07-15-2007 03:44 PM
hi
u have huge no of errors , that means ur line is faulty
165683 input errors, 7814 CRC, 76389 frame, 0 overrun, 0 ignored, 81477 abort <<<<<< contact ur servive provider if the same status after clearing the conter
" u can read my note on this form in Lease line problem"
252 carrier transitions << ur interface in go down and again coming up check the modem, clabele b/w router and the modem
regards
07-11-2007 06:43 AM
Check your LAN (not WAN) setting to verify that the DUPLEX (FUll / Half) are properly set and match at both ends.
Also check your cabling; if any of it is hand-made (versus "store-bought"), try replacing it with known good.
The problem is much more likely to be a LAN problem at one end or the other than a T1 problem, given the problem you've described.
Please post a "SH INT" for (at least) the serial interface(s) you're using to the WAN and the Ethernet LAN interfaces.
Good Luck
Scott
07-11-2007 06:53 AM
I did think that this may be a problem. On the LAN side there's a hub which the f0/0 plugs into which is a half duplex hub (not my design, just what was in place lol :P).
The S0/0 interfaces use ip unnumbered and take the ip address of the FA0/0 interface (again not my design)... The fa0/0 interface is running at 100/half because its connected to the hub.. Could this be a factor in the datarates? I can probably replace with a 10/100 switch to get at least full duplex connectivity..
07-11-2007 06:54 AM
I did think that this may be a problem. On the LAN side there's a hub which the f0/0 plugs into which is a half duplex hub (not my design, just what was in place lol :P).
The S0/0 interfaces use ip unnumbered and take the ip address of the FA0/0 interface (again not my design)... The fa0/0 interface is running at 100/half because its connected to the hub.. Could this be a factor in the datarates? I can probably replace with a 10/100 switch to get at least full duplex connectivity..
07-11-2007 07:46 AM
Hi,
Your T1 circuit using pairgain is working poorly. Likely a clock problem. Please check with the ISP that one of the pairgain units is generating clock.
Do not close the ticket until the error counter stays zero or very small over a 48h time period.
07-11-2007 09:48 AM
Ok, so the pairgains actually generate clocking, or they are in theory supposed to? I wasn't aware, I know the provider is generating the clocking, just I don't know where.
07-11-2007 10:47 AM
It is a "dry pair" circuit, so one pairgain unit has to generate clock on the loop, and the other will receive clock.
Both units are always giving clock toward the DTE (router), problem is that currently either something is very wrong with the physical loop, or as I said the units are not configured correctly.
You can pretty much exclude any router responsibility in a case like yours.
Good luck!
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