CRC and input errors on POS interface

[s-durando]

I have two Catalyst 6513 with a point-to-point 155Mbps connection between them. Even if I'm not trasmitting traffic between them, I see:

- input errors and CRCs increasing onlt on one side. The number of input errors and CRCs corresponds to the number of BIP(B3) errors in the output of 'show controller pos details'.

- FEBE counter increasing on the other side

These errors seem to be related only to control/signalling traffic. In fact if from one side I ping the other side of the point-to-point link I haven't packet loss, even if I use big sized packets.

I have changed encapsultaion from ppp to the default hdlc but the problem is still present.

Is it an hardware problem?

Thanks

Stefano

!

PDC-NGCSPDB-002#sh run int pos1/1/0

Building configuration...

Current configuration : 151 bytes

!

interface POS1/1/0

description MMC-NGCSMMB-002

bandwidth 155000

ip address 35.220.32.1 255.255.255.252

ip route-cache flow

pos framing sdh

end

!

!

MMC-NGCSMMB-002#sh run int pos1/1/0

Building configuration...

Current configuration : 166 bytes

!

interface POS1/1/0

description connessione con PDC-NGCSPD-002

bandwidth 155000

ip address 35.220.32.2 255.255.255.252

ip route-cache flow

pos framing sdh

end

!

PDC-NGCSPDB-002#sh int pos1/1/0

POS1/1/0 is up, line protocol is up

(...)

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

102 packets output, 13521 bytes, 0 underruns

0 output errors, 0 applique, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

PDC-NGCSPDB-002#

PDC-NGCSPDB-002#sh controllers pos det

POS1/1/0

SECTION

LOF = 0 LOS = 0 BIP(B1) = 0

LINE

AIS = 0 RDI = 0 FEBE = 0 BIP(B2) = 0

PATH

AIS = 0 RDI = 0 FEBE = 60 BIP(B3) = 0

PLM = 0 UNEQ = 0 TIM = 0 TIU = 0

LOP = 0 NEWPTR = 0 PSE = 0 NSE = 0

(...)

MMC-NGCSMMB-002#sh int pos1/1/0

POS1/1/0 is up, line protocol is up

(...)

404 input errors, 404 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

1407 packets output, 217990 bytes, 0 underruns

0 output errors, 0 applique, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

MMC-NGCSMMB-002#sh controllers pos det

POS1/1/0

SECTION

LOF = 0 LOS = 0 BIP(B1) = 0

LINE

AIS = 0 RDI = 0 FEBE = 0 BIP(B2) = 0

PATH

AIS = 0 RDI = 0 FEBE = 0 BIP(B3) = 402

PLM = 0 UNEQ = 0 TIM = 0 TIU = 0

LOP = 0 NEWPTR = 0 PSE = 0 NSE = 0

(...)

[beth-martin]

Ensure that both router ends of a POS link use the same CRC. Mismatched CRC settings are one configuration parameter to check when a POS interface stays up/down. Use the show interface command to confirm your settings. All Cisco POS interfaces support CRC-32. Higher-rate interfaces use CRC-32 as the default

[glbeach]

B3 errors when seen by themselves are almost always a provider issue.  When we troubleshoot POS Bit errors we narrow down the offending device by checking device to device in the path and finding the devices that show B2 and B1 errors.  If we see B1 errors the problem link is local.B3 errors when displayed by themselves represent a path error. From your controllers you appear to have a one way Path issue in the path toward MMC-NGCSMMB-002#.

Reference: http://www.cisco.com/en/US/tech/tk482/tk607/technologies_tech_note09186a0080094a79.shtml

See "when do partucilar BIP errors occur"