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New Member

Rapidly increasing "Total output drops" counter on a 6513

One of two 6513's increases the counter on ALL RJ45 ports of a 48-Port RJ45 FE Module, no matter if a cable is connected or not. About 20'000 - 30'000 drops per second ! VLAN membership independent. Other modules like GBIC-Blades are well, but not this FastEthernet module. CPU and interface load are little.

May we have a hardware problem on this module? Defect buffer memory ?

Here's a port config ex:


interface FastEthernet9/12

no ip address


switchport access vlan 2

switchport mode access


c6513-rz1-1#show interfaces fastEthernet 9/12

FastEthernet9/12 is up, line protocol is up

Hardware is C6k 100Mb 802.3, address is 0001.63d6.3e4d (bia


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

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

Encapsulation ARPA, loopback not set

Full-duplex, 100Mb/s

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

Last input never, output 00:00:06, output hang never

Last clearing of "show interface" counters never

Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops:41585838

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

37627906 packets input, 4622192613 bytes, 0 no buffer

Received 76970 broadcasts, 0 runts, 0 giants, 0 throttles

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

0 input packets with dribble condition detected

2706267307 packets output, 1116158169191 bytes, 0 underruns

0 output errors, 0 collisions, 3 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

Any suggestions or ideas will be great

Thanks and regards Peter

New Member

Re: Rapidly increasing "Total output drops" counter on a 6513

Hi Peter,

The FE module is faulty. As a test try swapping this FE module into the 2nd 6513 and see if the behaviour continues to confirm the problem lies with the module.

Find URL on output queue drops : suggesting this.

The section called Note under Output Queue Drops in the article describes a situation that fits the problem you 've described.

Here is what the note says below:

Note: There is one exception - if the output queue is constantly full and if no packets are being sent out of the interface at all, then it may be an indication of a hardware failure on the interface


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