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Packet losses between NEs due broken contacts on backplane bus

Publication Date:  2013-04-04 Views:  28 Downloads:  0
Issue Description


In such scheme customer tried to ping EKT-P-2 from OMS-PE-1 and had a losses.
At the same time ping between all directly connected interfaces was ok.
Handling Process

I checked all interfaces between sender and receiver, traffic policies, discards on interfaces. Everything was ok.

Then I created traffic policy witch will catch packets from sender:

acl name TEST
permit ip source 10.222.55.65 0

traffic classifier TEST
if-math TEST

traffic behavior TEST

traffic policy TEST
classifier TEST behavior TEST


Such policy I applied on all interfaces between sender and reciever and found out that OMS-P2 received all packets from OMS-PE1, but sent only part of them.

<OMS-P-NE80E-2>dis traffic policy statistics interface GigabitEthernet 1/1/0 in
Item                             Packets                      Bytes
-------------------------------------------------------------------
Matched                                50                          0
  +--Passed                            0                          0
  +--Dropped                           0                          0
    +--Filter                          0                          0
    +--URPF                            0                          0
    +--CAR                             0                          0
Missed                                97                      9,876

<OMS-P-NE80E-2>dis traffic policy statistics interface GigabitEthernet 9/1/0 out
Item                             Packets                      Bytes
-------------------------------------------------------------------
Matched                                43                          0
  +--Passed                            0                          0
  +--Dropped                           0                          0
    +--Filter                          0                          0
    +--URPF                            0                          0
    +--CAR                             0                          0
Missed                                110                      10,762


So packets were dropped on this device. There are now any another traffic policies, QoS configuration or another such suspecious things.

I ran display switch-port lpu 9 and found this:

<OMS-P-NE80E-2>dis switch-port lpu 9
SlotID:9  SERDES interface port status:
OPI port: status[SERDES interface NO.,portNO.]OUT/IN
 ON[0, 0]O  ON[0, 1]O  ON[0, 2]O  ON[0, 3]O
 ON[0, 4]O  ON[0, 5]O  ON[0, 6]O  ON[0, 7]O
 ON[0, 8]O  ON[0, 9]O  ON[0,10]O  ON[0,11]O
 ON[0,12]O  ON[0,13]O  ON[0,14]O  ON[0,15]O
 OFF[0,16]O  OFF[0,17]O  OFF[0,18]O  OFF[0,19]O

IPE port: status[SERDES interface NO.,portNO.]OUT/IN
 ON[0, 0]I  ON[0, 1]I  ON[0, 2]I  ON[0, 3]I
 LinkLost[0, 4]I  ON[0, 5]I  ON[0, 6]I  ON[0, 7]I
 ON[0, 8]I  ON[0, 9]I  ON[0,10]I  ON[0,11]I
 LinkLost[0,12]I  ON[0,13]I  ON[0,14]I  ON[0,15]I
 OFF[0,16]I  OFF[0,17]I  OFF[0,18]I  OFF[0,19]I


It means there is problem with interconnection between LPU and SFU.

Root Cause
I suggested to customer to do the folowing:
1) reset the board LPU9, check display switch-port lpu 9
2) replace the board LPU9, check display switch-port lpu 9, and check contacs on the board and backplane bus.

When customer plug out the board, he saw the reason as attachement.


Several contacts on the backplane bus were broken.
Solution

Replacing the chassis will completely solve this problem.

Suggestions
Be more accurate during plugging in the board.

END