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Problem with serial interfaces

All,

We have 6 T1s that are bundled in MLP. I noticed that we have CRCs on ALL of the serial interfaces, and I'm not sure why. Below is the result of "sh int | inc CRC".

14 input errors, 14 CRC, 10 frame, 6 overrun, 0 ignored, 7 abort

10 input errors, 10 CRC, 8 frame, 6 overrun, 0 ignored, 5 abort

30 input errors, 30 CRC, 22 frame, 17 overrun, 0 ignored, 8 abort

31 input errors, 31 CRC, 25 frame, 19 overrun, 0 ignored, 12 abort

28 input errors, 28 CRC, 25 frame, 20 overrun, 0 ignored, 14 abort

26 input errors, 26 CRC, 21 frame, 18 overrun, 0 ignored, 8 abort

What could cause this? CRCs are normally a physical problem (duplexing, bad cable, etc.), but I can't see all 6 circuits having an issue.

Thanks,

John

HTH, John *** Please rate all useful posts ***
5 REPLIES
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Re: Problem with serial interfaces

You have to compare against the packets received counter. If it 1000 is one thing, if it is 1,000,000 it's another.

Beside that, look at "show controllers T1" also.

Re: Problem with serial interfaces

The provider has run tests and they said that it's running clean to the csu. The only thing that I recently changed was the IOS, so I downgraded back to the original IOS last night and the problem remains. I still have a ton of CRC errors on all my interfaces.

Serial0/0/0:0 is up, line protocol is up

90 input errors, 90 CRC, 69 frame, 58 overrun, 0 ignored, 47 abort

Serial0/0/1:0 is up, line protocol is up

52 input errors, 52 CRC, 36 frame, 34 overrun, 0 ignored, 19 abort

Serial0/1/0:0 is up, line protocol is up

187 input errors, 187 CRC, 134 frame, 104 overrun, 0 ignored, 80 abort

Serial0/1/1:0 is up, line protocol is up

24 input errors, 24 CRC, 18 frame, 15 overrun, 0 ignored, 12 abort

Serial0/2/0:0 is up, line protocol is up

174 input errors, 174 CRC, 126 frame, 106 overrun, 0 ignored, 75 abort

Serial0/2/1:0 is up, line protocol is up

114 input errors, 114 CRC, 85 frame, 67 overrun, 0 ignored, 57 abort

They're all on my T1 WICs. "sh controlller t1" shows this:

Total Data (last 42 15 minute intervals):

0 Line Code Violations, 0 Path Code Violations,

1044 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,

1044 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 12 Unavail Secs

All of the interfaces have the errored secs in the same general range.

Is there anything I should be looking for at my end?

Thanks,

John

HTH, John *** Please rate all useful posts ***

Re: Problem with serial interfaces

Oh, and this is MLFR. All of my interfaces are configured like:

interface Serial0/0/0:0

no ip address

encapsulation frame-relay MFR0

no arp frame-relay

frame-relay multilink lid link1

with the frame-relay line multilink lid linkx changing for each interface: link2, link3, link4, link5, and link6.

John

HTH, John *** Please rate all useful posts ***
Blue

Re: Problem with serial interfaces

John:

Those Slip seconds caught my eye.

Have you checked how the timing is configured for each circuit and the bundle as well?

Typically, the router interfaces should be set for line timing.

HTH

Victor

Re: Problem with serial interfaces

Victor,

We had to clear counters on this since we changed a couple of things, but it didn't help. My clock source is line:

Applique type is Channelized T1

Cablelength is long gain36 0db

No alarms detected.

alarm-trigger is not set

Soaking time: 3, Clearance time: 10

AIS State:Clear LOS State:Clear LOF State:Clear

Version info Firmware: 20040802, FPGA: 13, spm_count = 0

Framing is ESF, Line Code is B8ZS, Clock Source is Line.

CRC Threshold is 320. Reported from firmware is 320.

Data in current interval (511 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

14 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

14 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Here are the configuration for the controllers, multilink, and serial:

controller T1 0/0/0

framing esf

linecode b8zs

channel-group 0 timeslots 1-24

interface MFR0

no ip address

load-interval 30

frame-relay multilink bid DataCenter

frame-relay lmi-type ansi

!

interface MFR0.790 point-to-point

ip address

no cdp enable

frame-relay interface-dlci 790 IETF

interface Serial0/0/0:0

no ip address

encapsulation frame-relay MFR0

no arp frame-relay

frame-relay multilink lid link1

Thanks,

John

HTH, John *** Please rate all useful posts ***
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