03-12-2014 07:24 AM - edited 03-07-2019 06:40 PM
Hello,
on my Cisco WS-C2960-48TC-S i have 82933027 output drops on the access interface.
this interface is connected to only one computer, does someone have an idea how this is posible ??
L2_HHP-21#sh int fa0/12
FastEthernet0/12 is up, line protocol is up (connected)
Hardware is Fast Ethernet, address is d4a0.2a6c.6236 (bia d4a0.2a6c.6236)
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 2/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, media type is 10/100BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 82933027
Queueing strategy: fifo
Output queue: 0/0 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 997000 bits/sec, 202 packets/sec
161016 packets input, 20059528 bytes, 0 no buffer
Received 12237 broadcasts (8646 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 8646 multicast, 0 pause input
0 input packets with dribble condition detected
90278417 packets output, 25066682913 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 PAUSE output
0 output buffer failures, 0 output buffers swapped out
Switch#sh run int fa0/12
Building configuration...
Current configuration : 168 bytes
!
interface FastEthernet0/12
switchport access vlan 30
switchport mode access
switchport voice vlan 244
spanning-tree portfast
spanning-tree bpduguard enable
end
L2_HHP-21#sh mac add int fa0/12
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
30 0010.f32e.6236 DYNAMIC Fa0/12
Total Mac Addresses for this criterion: 1
03-12-2014 10:42 AM
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Generally it's caused by sending packets to the interface faster than they can egress the interface.
On some switches, I think the 2960 being one of them, QoS being enabled on the switch, in a default configuration, often results in premature packet dropping due to default buffer reservations for QoS egress queues.
03-12-2014 12:37 PM
Hello joseph thank you for your answer.
I have checked the global configuration but no QOS settings are enabled.
The output drops are not really high but i still have them.
This morning i reset the counters and now i have again "output drops: 2956"
it is just an interface connected to a computer so it is strange that it has the output drops.
FastEthernet0/2 is up, line protocol is up (connected)
Hardware is Fast Ethernet, address is a456.308c.3102 (bia a456.308c.3102)
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 12/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, media type is 10/100BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:00, output hang never
Last clearing of "show interface" counters 05:19:54
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 2956
Queueing strategy: fifo
Output queue: 0/0 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 4829000 bits/sec, 861 packets/sec
10314 packets input, 1015389 bytes, 0 no buffer
Received 1674 broadcasts (1373 multicasts)
Fa0/2 connected 30 a-full a-100 10/100BaseTX
sh mac add int fa0/2
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
30 0010.f325.e554 DYNAMIC Fa0/2
Total Mac Addresses for this criterion: 1
03-12-2014 01:03 PM
What's the output packet count (that corresponds to your drop count)?
03-12-2014 01:08 PM
could you explain a little bit more, where can i find the output count ?
03-12-2014 03:27 PM
03-13-2014 01:39 PM
Hello Leo thank you for your answer.
The iios version is: c2960-lanlitek9-mz.122-50.SE5.bin
03-13-2014 03:05 PM
Michael,
Upgrade your IOS to 12.2(55)SE8.
03-12-2014 01:11 PM
the thing is, the output drops just occur sometimes.
like now it did not have any additional output drops for 1 hour, the count stays at 2956 so it is sometimes.
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