Input Drops Increasing in Switch Port

[Ajay Raj]

Hi,

I'm seeing input queue drops increasing in cisco WS-C6509. What could be the reason,Is it bcoz of any qos issue?

#sh int g1/5 | in drop

  Input queue: 0/2000/1285737/0 (size/max/drops/flushes); Total output drops: 0

interface GigabitEthernet1/5

no ip address

wrr-queue bandwidth 1 5 50

wrr-queue queue-limit 50 30 20

wrr-queue random-detect min-threshold 1 80 100 100 100 100 100 100 100

wrr-queue random-detect min-threshold 2 50 70 90 100 100 100 100 100

wrr-queue random-detect min-threshold 3 50 70 100 100 100 100 100 100

wrr-queue random-detect max-threshold 1 100 100 100 100 100 100 100 100

wrr-queue random-detect max-threshold 2 60 80 100 100 100 100 100 100

wrr-queue random-detect max-threshold 3 60 80 100 100 100 100 100 100

wrr-queue cos-map 2 1 1

wrr-queue cos-map 2 2 2

wrr-queue cos-map 2 3 4

wrr-queue cos-map 3 1 3

wrr-queue cos-map 3 2 6

wrr-queue cos-map 3 3 7

rcv-queue threshold 1 50 60 65 75 80 85 90 100

rcv-queue cos-map 1 2 1

rcv-queue cos-map 1 3 2

rcv-queue cos-map 1 4 4

rcv-queue cos-map 1 5 3

rcv-queue cos-map 1 6 6

rcv-queue cos-map 1 7 7

rcv-queue cos-map 1 8 5

mls qos trust dscp

switchport

switchport access vlan 100

switchport mode access

end

[Leo Laohoo]

Post the following outputs:

1.  sh counter interface G1/5;

2.  sh interface G1/5;

3.  sh version; and

4.  sh module

[Ajay Raj]

Hi,

I've attached all the details...

[Leo Laohoo]

Here's my take ...

If you have QoS issues, you'd see a lot of output drops.  But in your particular case, you have none.  Now I'm not sure that this is caused by an IOS bug or not. 

The output to the "sh interface", however, has shown that the interface has some "Input Errors".  The "sh counters" is suppose to verify which line errors you are getting.  But this is where everything starts going "wierd". 

If you look into your "sh counters" output, look at the second segment, the 32-bit counters.  Those values are suppose to be 0.  But in your output the 32-bit counters have values.  THE SAME VALUES. 

Look further down under "All Port Counters".  Again, same values where line errors are occuring.

Line errors such as FCS, Alignment, etc. are all zero.  No collissions.

I'm beginning to believe whatever is downstream is causing some issues.  What is the downstream client to this port?

[Ajay Raj]

Device connected to this port is WS-C6506. But when I give "sh inter switching" its showing drops in RP. Is this causing the issue?

#sh cdp neighbors g1/5

Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge

                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID

xxxxxx                    Gig 1/5            166         T S I     WS-C6506  2/4

Switch2#    sh int g1/5 switching

GigabitEthernet1/5 Energis-t244-r94-002-Port2/4

          Throttle count          0

        Drops         RP    1285842         SP          0

  SPD Flushes       Fast          0        SSE          0

  SPD Aggress       Fast          0

SPD Priority     Inputs          0      Drops          0

     Protocol       Path    Pkts In   Chars In   Pkts Out  Chars Out

        Other    Process    4171444  233600864          0          0

            Cache misses          0

                    Fast          0          0          0          0

               Auton/SSE          0          0          0          0

Spanning Tree    Process      27393    1178110   62227220 2674481344

            Cache misses          0

                    Fast          0          0          0          0

               Auton/SSE          0          0          0          0

          CDP    Process    2087856  538666848    2088683 1008833871

            Cache misses          0

                    Fast          0          0          0          0

               Auton/SSE          0          0          0          0

[Ahmad Mohaidat]

Hello ,
Yes this is most likely what is causing your issue , first of all you need to know why these packets are coming to the input queue , the traffic that is punted to the cpu will be queued in the input queue and we understand why.

Kindly try to capture the output of "show buffer input-interface gig 5/1 packet" multiple times , this should give uz an idea about the nature of the traffic comint to this interface and punted to the cpu.

HTH.
Ahmad.


Sent from Cisco Technical Support Android App

[Ajay Raj]

Hi,

I'm not getting anything in buffer.

Switch2#show buffer input-interface gig 5/1 packe

Switch2#

[Ahmad Mohaidat]

Hello Ajay,
You need to issue the command multiple times , the command will give you an output only when there is a packet in the input queue.

HTH.
Ahmad.

Sent from Cisco Technical Support Android App

[Ajay Raj]

Hi,

I tried lot of times, I cant see anything in buffer.

I can see drop count same as input errors and nothing in queue size.

Input queue: 0/2000/2537/0 (size/max/drops/flushes); Total output drops: 0

2537 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored