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what does mean System FCS error frames?

I have a C2960G that is some issue.

This problem is ping success DA(GOOGLE),also it doesnt  open same web site for port 0/1 ~ 0/4.

other port successed ping and web site that just changed port.

what does reason this problem?

I think 0/1 ~0/4 port is same ASIC that is fault.

Let me know what is problem?


     Transmit GigabitEthernet0/1              Receive
   1316853346 Bytes                       4196492763 Bytes                   
    319528358 Unicast frames               337351001 Unicast frames          
    208877933 Multicast frames                 12929 Multicast frames        
     34631197 Broadcast frames                765178 Broadcast frames        
            0 Too old frames              4094646794 Unicast bytes           
            2 Deferred frames                1817312 Multicast bytes         
            0 MTU exceeded frames          100026768 Broadcast bytes         
            3 1 collision frames                   0 Alignment errors        
            0 2 collision frames                  10 FCS errors              
            0 3 collision frames                   0 Oversize frames         
            0 4 collision frames                   0 Undersize frames        
            0 5 collision frames                   2 Collision fragments     
            0 6 collision frames      
            0 7 collision frames            95891476 Minimum size frames     
            0 8 collision frames           116359585 65 to 127 byte frames   
            0 9 collision frames            59470400 128 to 255 byte frames  
            0 10 collision frames           28961467 256 to 511 byte frames  
            0 11 collision frames           14288550 512 to 1023 byte frames 
            0 12 collision frames           23157642 1024 to 1518 byte frames
            0 13 collision frames                  0 Overrun frames          
            0 14 collision frames                  0 Pause frames            
            0 15 collision frames     
            0 Excessive collisions                 2 Symbol error frames     
           11 Late collisions                      0 Invalid frames, too large
            0 VLAN discard frames                  0 Valid frames, too large 
            0 Excess defer frames                  2 Invalid frames, too small
     98381126 64 byte frames                       0 Valid frames, too small 
    200223276 127 byte frames         
     39551381 255 byte frames                      0 Too old frames          
    176560369 511 byte frames                      0 Valid oversize frames   
     29278568 1023 byte frames               3390830 System FCS error frames 
     22433608 1518 byte frames                     0 RxPortFifoFull drop frame
            0 Too large frames        
            2 Good (1 coll) frames    
            0 Good (>1 coll) frames   

Reza Sharifi
Hall of Fame Expert


Excessive errors for certain counters usually indicate a problem. When       you operate at half-duplex setting, some data link errors incrementing in Frame       Check Sequence (FCS), alignment, runts, and collision counters are normal.       Generally, a one percent ratio of errors to total traffic is acceptable for       half-duplex connections. If the ratio of errors to input packets is greater       than two or three percent, performance degradation can be noticed.

In half-duplex environments, it is possible for both the switch and the       connected device to sense the wire and transmit at exactly the same time and       result in a collision. Collisions can cause runts, FCS, and alignment errors       due to the frame not being completely copied to the wire, which results in       fragmented frames.

When you operate at full-duplex, errors in FCS, Cyclic Redundancy       Checks (CRC), alignment, and runt counters must be minimal. If the link       operates at full-duplex, the collision counter is not active. If the FCS, CRC,       alignment, or runt counters increment, check for a duplex mismatch. Duplex       mismatch is a situation where the switch operates at full-duplex and the       connected device operates at half-duplex, or vice versa. The results of a       duplex mismatch are extremely slow performance, intermittent connectivity, and       loss of connection. Other possible causes of data link errors at full-duplex       are bad cables, faulty switch ports, or NIC software/hardware issues. See the       Common Port and Interface Problems section of       this document for more information.

more info:


Leo Laohoo
VIP Community Legend

Look at the Transmit column.  You have "11" Late collisions.  You have "3" 1 collision frames.

Look at the Receive column. 

Yes, your Systems FCS is very high.

Run a TDR test from your 2960G.


now it just dont use port before i used to be usage with port 0/1 -0/4

and we already physical test.

GigabitEthernet0/1 is down, line protocol is down (notconnect)

Hardware is Gigabit Ethernet, address is aca0.162c.7c01 (bia aca0.162c.7c01)

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

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

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Auto-duplex, Auto-speed, media type is 10/100/1000BaseTX

input flow-control is off, output flow-control is unsupported

ARP type: ARPA, ARP Timeout 04:00:00

Last input 1w5d, output 00:35:25, output hang never

Last clearing of "show interface" counters 1w0d

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

1653 packets input, 156708 bytes, 0 no buffer

Received 582 broadcasts (310 multicasts)

0 runts, 0 giants, 0 throttles

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

0 watchdog, 310 multicast, 0 pause input

0 input packets with dribble condition detected

11302 packets output, 2690664 bytes, 0 underruns

0 output errors, 3 collisions, 0 interface resets

0 babbles, 11 late collision, 0 deferred

0 lost carrier, 0 no carrier, 0 PAUSE output

0 output buffer failures, 0 output buffers swapped out

0 output buffer failures, 0 output buffers swapped out

I replace the HW and than it will be ok.

at the time its problems, if you have it, you can be replacememt it.

thank you for answering.