Output Drops on GRE tunnel

[mahesh18]

                   Hi Everyone,

4500 device has config for GRE only.

I cleared the counters but drops are incrementing rapidly

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

  Encapsulation TUNNEL, loopback not set

  Keepalive not set

  Tunnel source 192.168.130.254 (Loopback3), destination 192.168.128.254

  Tunnel protocol/transport GRE/IP

    Key disabled, sequencing disabled

    Checksumming of packets disabled

  Tunnel TTL 255, Fast tunneling enabled

  Tunnel transport MTU 1476 bytes

  Last input never, output never, output hang never

  Last clearing of "show interface" counters 02:44:05

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 2125

  Queueing strategy: fifo

  Output queue: 0/0 (size/max)

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

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

     0 packets input, 0 bytes, 0 no buffer

     Received 0 broadcasts (0 IP multicasts)

     0 runts, 0 giants, 0 throttles

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

     2125 packets output, 127500 bytes, 0 underruns

     0 output errors, 0 collisions, 0 interface resets

     0 output buffer failures, 0 output buffers swapped out

Here it does not show much data going via tunnel

Tunnel config is

interface Tunnel1

ip address 192.168.124.2 255.255.255.252

delay 7

tunnel source Loopback3

tunnel destination 192.168.128.254

Need to know why total drops are incrementing and how can i check if data is passing via tunnel as currenlty transmit and receive load is empty.

thanks

mahesh

[Rudy Sanjoko · Accepted solution]

Have you verified the connection to the other end through the tunnel  interface? does it works? I see that the value of packets on output and  that is being dropped have  the same value, can you try to set the mtu  value on the tunnel to 1400 and see if this solve your issue with the  drops.

My assumption to your question regarding the input  ouput rates  are 0 is because there is no traffic able to pass through  that interface  yet. The most common reasons of output drop on tunnel  are MTU, CPU and  encapsulation failure.

[mahesh18]

Hi Rudy,

Thanks for reply back.

I did more digging and found that the tunnel is not in use.

Its has no config on remote end.

Mahesh