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New Member

Bit Error Rate BER B3 logs filling up



I have a router connected to a provider via POS and once we commissioned the link we are receiving the following logs



010091: .May  7 06:58:34.353 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface POSx/x/x, changed state to down

010092: .May  7 06:59:04.320 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface POSx/x/x, changed state to up

010093: .May  7 06:59:12.317 UTC: %ASR1000_RP_SONET_ALARM-6-SONET: ASSERT CRITICAL POSx/x/x Threshold Cross Alarm - B3

010094: .May  7 06:59:12.317 UTC: %SONET-4-ALARM: SIP0/1:  POS0/1/0: B3 BER exceeds threshold, TC alert declared


The actual interface is configured as below.



interface POSXXX


no ip address

no ip redirects

no ip unreachables


encapsulation frame-relay IETF

load-interval 30

crc 32

pos framing sdh

pos scramble-atm

frame-relay lmi-type ansi


Question :   what can be the following causes ? Is it the router POS interface which is creating in payload corruption ?

Hall of Fame Super Gold

You've got a layer 1 issue.

You've got a layer 1 issue.  Please post the output to the command "sh interface POS <BLAH>".

New Member

sh int pos 0/1/0POS0/1/0 is

sh int pos 0/1/0

POS0/1/0 is up, line protocol is up

  Hardware is SPA-1XOC12-POS


  MTU 4470 bytes, BW 622000 Kbit/sec, DLY 100 usec,

     reliability 255/255, txload 1/255, rxload 4/255

  Encapsulation FRAME-RELAY IETF, crc 32, loopback not set

  Keepalive set (10 sec)

  Scramble enabled

  LMI enq sent  91286, LMI stat recvd 91273, 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  segmentation inactive

  FR SVC disabled, LAPF state down

  Broadcast queue 0/256, broadcasts sent/dropped 0/0, interface broadcasts 0

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

  Last clearing of "show interface" counters 1w3d

  Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 371

  Queueing strategy: Class-based queueing

  Output queue: 0/40 (size/max)

  30 second input rate 9930000 bits/sec, 2470 packets/sec

  30 second output rate 1752000 bits/sec, 2236 packets/sec

     2041953470 packets input, 819671035376 bytes, 0 no buffer

     Received 0 broadcasts (0 IP multicasts)

     968195 runts, 23 giants, 0 throttles

              0 parity

     1008516 input errors, 38377 CRC, 0 frame, 0 overrun, 0 ignored, 1921 abort

     1893429862 packets output, 205010313695 bytes, 0 underruns

     0 output errors, 0 applique, 0 interface resets

     0 unknown protocol drops

     0 output buffer failures, 0 output buffers swapped out

     0 carrier transitions

Hall of Fame Super Gold

1008516 input errors, 38377

     1008516 input errors, 38377 CRC, 0 frame, 0 overrun, 0 ignored, 1921 abort

It's confirmed that your line is dirty.  Get the telco to run an end-to-end Bit Error Rate (BER) test.