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Networking

The MSC device is directly connected to an NE router. After the cutover, the MSC device is directly connected to an S series switch, and packet loss occurs on the MSC device.

Fault Symptom

A large number of packets are discarded before and after the cutover.

Cause Analysis

After logs are checked, it is found that the auto-negotiated rate of the 1000M interface connecting the MSC device to the S series switch is only 10 Mbit/s, and the number of discarded packets exceeds the threshold. It is recommended that interfaces at both ends of a link work in non-auto-negotiation mode.

Troubleshooting Procedure

1.         Log in to the S series switch, and run the display interface GigabitEthernet 0/0/5 command in any view to check the status of GE0/0/5 connected to the MSC device.

<HUAWEI> display interface GigabitEthernet 0/0/5
GigabitEthernet0/0/5 current state : DOWN
Line protocol current state : DOWN
Description:
Switch Port, PVID : 3957, TPID : 8100(Hex), The Maximum Frame Length is 9216
IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is 0425-c597-4dc0
Current system time: 2017-11-01 18:29+01:00
Port Mode: COMMON COPPER, Transceiver: 1000_BASE_T_SFP
Speed : 1000,   Loopback: NONE
Duplex: FULL,   Negotiation: ENABLE //The interface works in auto-negotiation mode.
Mdi   : AUTO,   Flow-control: DISABLE
Last 300 seconds input rate 0 bits/sec, 0 packets/sec
Last 300 seconds output rate 0 bits/sec, 0 packets/sec
Input peak rate 35877408 bits/sec, Record time: 2017-11-01 18:29
Output peak rate 33694256 bits/sec, Record time: 2017-11-01 18:29
 
Input:  102615936 packets, 31409886697 bytes
  Unicast:                  102595943,  Multicast:                         502
  Broadcast:                    19470,  Jumbo:                               0
  Discard:                          0,  Pause:                               0
  Frames:                           0
 
  Total Error:                     21
  CRC:                             12,  Giants:                              0
  Jabbers:                          0,  Fragments:                           8
  Runts:                            0,  DropEvents:                          0
  Alignments:                       0,  Symbols:                             1
  Ignoreds:                         0
 
Output:  127584698 packets, 34122796642 bytes
  Unicast:                  127511799,  Multicast:                        1632
  Broadcast:                    71267,  Jumbo:                               0
  Discard:                  127147932,  Pause:                               0  //A large number of packets are discarded.
 
  Total Error:                      0
  Collisions:                       0,  ExcessiveCollisions:                 0
  Late Collisions:                  0,  Deferreds:                           0
  Buffers Purged:                   0
 
    Input bandwidth utilization threshold : 80.00%
    Output bandwidth utilization threshold: 80.00%
    Input bandwidth utilization  :    0%
    Output bandwidth utilization :    0%

2.         Run the display logbuffer command in any view. The command output shows that GE0/0/5 frequently alternates between Up and Down.

<HUAWEI> display logbuffer
Logging buffer configuration and contents : enabled                             
Allowed max buffer size : 1024                                                  
Actual buffer size : 512                                                         
Channel number : 4 , Channel name : logbuffer                                   
Dropped messages : 0                                                            
Overwritten messages : 0                                                        
Current messages : 109  
Nov  1 2017 11:17:45+01:00 Utex-CS-S5300-1 %IFNET/4/LINK_STATE(l)[14]:The line protocol IP on the interface GigabitEthernet0/0/5 has entered the DOWN state.
Nov  1 2017 11:17:45+01:00 Utex-CS-S5300-1 %IFPDT/4/IF_STATE(l)[15]:Interface GigabitEthernet0/0/5 has turned into DOWN state.
Nov  1 2017 11:15:38+01:00 Utex-CS-S5300-1 %IFNET/4/LINK_STATE(l)[16]:The line protocol IP on the interface GigabitEthernet0/0/5 has entered the UP state.
Nov  1 2017 11:15:38+01:00 Utex-CS-S5300-1 %IFPDT/4/IF_STATE(l)[17]:Interface GigabitEthernet0/0/5 has turned into UP state.
Nov  1 2017 11:15:32+01:00 Utex-CS-S5300-1 %IFNET/4/LINK_STATE(l)[18]:The line protocol IP on the interface GigabitEthernet0/0/5 has entered the DOWN state.
Nov  1 2017 11:15:32+01:00 Utex-CS-S5300-1 %IFPDT/4/IF_STATE(l)[19]:Interface GigabitEthernet0/0/5 has turned into DOWN state.
Nov  1 2017 11:15:24+01:00 Utex-CS-S5300-1 %IFNET/4/LINK_STATE(l)[20]:The line protocol IP on the interface GigabitEthernet0/0/5 has entered the UP state.
Nov  1 2017 11:15:06+01:00 Utex-CS-S5300-1 %IFPDT/4/IF_STATE(l)[21]:Interface GigabitEthernet0/0/5 has turned into UP state.
Nov  1 2017 11:15:00+01:00 Utex-CS-S5300-1 %IFPDT/4/IF_STATE(l)[22]:Interface GigabitEthernet0/0/5 has turned into DOWN state.
Nov  1 2017 11:12:07+01:00 Utex-CS-S5300-1 %IFPDT/4/IF_STATE(l)[23]:Interface GigabitEthernet0/0/5 has turned into UP state.

3.         Run the display diag-logfile buffer command in the diagnostic view to check diagnostic logs. The command output shows that the interface rate is negotiated to 10 Mbit/s when the status of GE0/0/5 is Up, and the number of discarded packets exceeds the threshold.

<HUAWEI> system-view 
[HUAWEI] diagnose
[HUAWEI-diagnose] display  diag-logfile  buffer 
... ...
Line 37198: Nov 1 2017 01:43:04.70.3+01:00 Utex-CS-S5300-1 %IFPDT/4/DUPLEX_HALF(D)[4174]:Interface GigabitEthernet0/0/5 duplex mode log. (PhyStatus=DOWN, PreDuplex=FULL, CurrDuplex=HALF, Speed=0M, Function=IFPDT_ChangePortStatus, Line=909)
Line 37199: Nov 1 2017 01:43:41.750.1+01:00 Utex-CS-S5300-1 %IFPDT/6/SYNC_NPTABLE(D)[4175]:Start syncing NP table.(IfName=GigabitEthernet0/0/5, PortStatus=1, Function=IFAGT_PortStatusToAllBoard, Line=1884)
Line 37200: Nov 1 2017 01:43:41.750.2+01:00 Utex-CS-S5300-1 %IFPDT/4/DUPLEX_HALF(D)[4176]:Interface GigabitEthernet0/0/5 duplex mode log. (PhyStatus=UP, PreDuplex=FULL, CurrDuplex=FULL, Speed=10M, Function=IFPDT_ChangePortStatus, Line=909)
Line 37209: Nov 1 2017 01:51:35.140.1+01:00 Utex-CS-S5300-1 %IFPDT/6/SYNC_NPTABLE(D)[4185]:Start syncing NP table.(IfName=GigabitEthernet0/0/5, PortStatus=0, Function=IFAGT_PortStatusToAllBoard, Line=1884)
Line 37210: Nov 1 2017 01:51:35.140.2+01:00 Utex-CS-S5300-1 %IFPDT/4/DUPLEX_HALF(D)[4186]:Interface GigabitEthernet0/0/5 duplex mode log. (PhyStatus=DOWN, PreDuplex=FULL, CurrDuplex=HALF, Speed=0M, Function=IFPDT_ChangePortStatus, Line=909)
Line 37211: Nov 1 2017 01:52:20.410.2+01:00 Utex-CS-S5300-1 %IFPDT/6/SYNC_NPTABLE(D)[4187]:Start syncing NP table.(IfName=GigabitEthernet0/0/5, PortStatus=1, Function=IFAGT_PortStatusToAllBoard, Line=1884)
 

4.         Attempt to configure GE0/0/5 on the S series switch to work in non-auto-negotiation mode and forcibly work at 1000 Mbit/s. In addition, the interface on the peer device also works in non-auto-negotiation mode, and the problem is resolved.

<HUAWEI> system-view
[HUAWEI] intface GigabitEthernet  0/0/5  
[HUAWEI-GigabitEthernet0/0/5] undo negotiation auto
[HUAWEI-GigabitEthernet0/0/5] speed 1000

Conclusions and Suggestions

Interfaces at both ends of a link must use the same negotiation mode. If they use different negotiation modes, for example, the local device works in non-auto-negotiation mode and the peer device works in auto-negotiation mode, the local interface may be Up or Down, but the peer interface is always Down. If two connected interfaces work in non-auto-negotiation mode, you need to configure the same interface rate for them.