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interface output errors

Level 3
Level 3


on one end i have WS-C3850-48P and on the other end i have WS-C2960X-48FPD-L. Daily for sometime i receive alert for output error on particular interfaces which are part of portchannel of WS-C3850-48P. Daily i face this issue during business hours particularly on those ports. while on the other end (WS-C2960X-48FPD-L) there are no errors. what steps should i follow to troubleshoot this issue.

GigabitEthernet1/0/47 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is 00a2.89d4.77af (bia 00a2.89d4.77af)
Description:  G1/0/47
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, 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 00:00:01, output never, output hang never
Last clearing of "show interface" counters 24w4d
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 2114058
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 5000 bits/sec, 7 packets/sec
5 minute output rate 24000 bits/sec, 25 packets/sec
1026930025 packets input, 112466646250 bytes, 0 no buffer
Received 24954970 broadcasts (12794372 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 12794372 multicast, 0 pause input
0 input packets with dribble condition detected
618833910 packets output, 93620061474 bytes, 0 underruns
2114058 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
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

On both end show int status show a-1000 and full duplex

#sh int status

Gi1/0/47  Switch  connected    trunk      a-full a-1000 10/100/1000BaseTX

#sh int gigabitEthernet 1/0/47 counters errors

Port      Align-Err FCS-Err   Xmit-Err     Rcv-Err  UnderSize OutDiscards
Gi1/0/47 0                 0        2114058         0          0               2114058

Port             Single-Col Multi-Col Late-Col Excess-Col Carri-Sen Runts
Gi1/0/47           0                  0             0              0             0          0

20 Replies 20

hi Joseph, i think it's not necessary, the issue is the reported in the first message, and no specific solution was provided
i should be goog to close this topic if we can find any other tip to solve this issue

Whether you want to open a new posting or not, one major reason I suggested opening new is this thread was originally posted 5/17 and edited 3/19, both rather old/stale.

Although it makes sense to find possible solutions from years ago, most, I suspect, don't look to solve open issues, from years ago.

Plus, if you're not the original poster, you cannot mark an answer as a solution!

Hi Leo,


In my case, the values are not the same.


Switch#sh int GigabitEthernet0/2 controller 

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 89

89 output errors, 0 collisions, 0 interface resets

 0 Excess defer frames 

Swicth#sh run int GigabitEthernet0/2
Building configuration...

Current configuration : 137 bytes
interface GigabitEthernet0/2
description **Conneceted to Firewall-Port 19**
switchport access vlan 140
switchport mode access


What needs to be done. Please advise

Hi Leo,

I'm encountering this same issue I checked the interface controller and the output errors and Excess Defer Frames are the same value. May I know how to resolve this kind of issue relating to QoS? Thanks a lot!

Also have same problem on WS-C3650-48TD switch getting output error on interface

Port Align-Err FCS-Err Xmit-Err Rcv-Err UnderSize OutDiscards
Gi1/0/26 0 0 434465 0 0 434465
Port Single-Col Multi-Col Late-Col Excess-Col Carri-Sen Runts
Gi1/0/26 0 0 0 0 0 0

what step to start troubleshoot this issue.

Often dropped packets on egress are due to egress buffer/queue overflow. First trouble shooting steps are to determine percentage of drops of egress packets, also whether drops happen in "clusters", and also whether applications are being adversely impacted. (I.e. first determine if there's a real problem before you try to "solve" it.)
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