Re: Input errors on p2p T1

jheckart · ‎11-14-2006

I've recently moved a channelized T3 from 1 facility to another. I have 6 T1's channeled off of the T3. Prior to the move, all channels were working fine, and taking no known errors. After the move, I have a T1 that is taking input errors on the side of the T3.

I have been working with the telco, which has been an absolute pain, but they claim that they are clean to the extended demarc, and that the problem is within my equipment.

My equipment is as follows:

7204VXR w/PA-MC-2T3 (DS3)

3725 w/WIC-2T and Adtran CSU/DSU

For the T1 that is having the problem, I have swapped the WIC-2T, and tried three different CSU/DSU's, and DTE cables to no avail. I then started looking at the clocking, and tried setting the clocking to internal on the CSU/DSU. After clocking the CSU/DSU to internal, I am able to do 10,000 test pings at 2,000 bytes per packet over this circuit with no loss. However, I am seeing a minimal amount of input errors on the side of the T3. As of now, I am seeing a ratio of input errors to input packets of 0.0003.

The question is, what else should I look at, and should I just be happy with this amount of error when no degredation in performance exists?

Thanks.

spremkumar · ‎11-14-2006

Hi

Did you try normal standard 64 byte ping with 1000 or 10000 ping counts ?

Are you seeing any errors while doing so ?

Also can you paste the show interface output here ?

Other way will be clear the counters and watch out for errors on the interface with normal traffic without any pinging excercise.

That will also give you some idea about the reliability of the T1 pipe connected on the router.

regds

jheckart · ‎11-15-2006

In my previous post, I stated that I was able to do a test of 10,000 100 and 1,000 byte pings without any loss.

I cleared counters on both ends and tried 1,000 64-byte pings, and had no loss.

Prior to clearing counters today, my 3725 showed no errors, and the 7204VXR showed 3,200 input errors, and 5,000,000 total packets input. The ratio for that is 0.00064.

T1 Side (3725):

Internet address is 192.168.239.14/30

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 15/255, rxload 9/255

Encapsulation PPP, LCP Open

Open: IPCP, CDPCP, loopback not set

Keepalive set (10 sec)

Last input 00:00:01, output 00:00:00, output hang never

Last clearing of "show interface" counters 00:03:07

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: Class-based queueing

Output queue: 0/1000/64/0 (size/max total/threshold/drops)

Conversations 0/40/256 (active/max active/max total)

Reserved Conversations 2/2 (allocated/max allocated)

Available Bandwidth 50 kilobits/sec

5 minute input rate 60000 bits/sec, 11 packets/sec

5 minute output rate 94000 bits/sec, 31 packets/sec

5709 packets input, 419042 bytes, 0 no buffer

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

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

8734 packets output, 1156898 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

DCD=up DSR=up DTR=up RTS=up CTS=up

Channelized T3 (7204VXR):

Internet address is 192.168.239.13/30

MTU 1500 bytes, BW 1536 Kbit, DLY 20000 usec,

reliability 255/255, txload 16/255, rxload 19/255

Encapsulation PPP, LCP Open

Open: IPCP, CDPCP, crc 16, 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 00:00:31

Input queue: 1/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: Class-based queueing

Output queue: 0/1000/64/0 (size/max total/threshold/drops)

Conversations 0/4/256 (active/max active/max total)

Reserved Conversations 2/2 (allocated/max allocated)

Available Bandwidth 44 kilobits/sec

5 minute input rate 118000 bits/sec, 24 packets/sec

5 minute output rate 99000 bits/sec, 12 packets/sec

1317 packets input, 102272 bytes, 0 no buffer

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

1 input errors, 0 CRC, 1 frame, 0 overrun, 0 ignored, 0 abort

1019 packets output, 78775 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions no alarm present

Timeslot(s) Used: 1-24, subrate: 1536Kb/s, transmit delay is 0 flags

non-inverted data

spremkumar · ‎11-15-2006

Hi

Is there any specific criteria for running PPP as encapsulation in your routers ?

I see you are also running Class based queuing on both the ends.

Under the available bandwidth theres a slight mismatch on both the ends..

Available Bandwidth 50 kilobits/sec

Available Bandwidth 44 kilobits/sec

AFAIK ICMP packets will be given least priority and it may be dropped in due course on its way if the traffic defined in other classes effectively uses the bandwidth configured/allocated to them.

So i dont think so its an alarming factor if you see mere amount of errors on your interface.

regds

jheckart · ‎11-15-2006

spremkumar,

Thanks.

I guess that the root of the question here is, should I have had to set one side of this p2p T1's CSU/DSU to use it's internal clock to minimize errors?