Drops on Tunnel interface

Unanswered Question
Sep 4th, 2009

Hi,

I am getting drops on tunnel interface on the router. Tunnel interface and configurations are attached with this email. This is a 5 Mbps link on fiber and the traffic is going not above 2.5 Mbps but still I am getting drops. There are no drops on the physical interface whereas drops are seen on the tunnel interface.

Regards,

Asim

Attachment: 
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u1kumar2002 Fri, 09/04/2009 - 23:01

Hi Saad,

If you are facing drops in tunnel interface Plz check the usage. If the usage is more than physical link bandwidth. This could be one reason.

I don't know how to open the attachment i this forum. Can u plz share that how i can see u attachment. So that i can get better understanding. I am new in this forum.I tried but i am not able to see the attachment

waridtel.com Sat, 09/05/2009 - 01:03

Hi,

The physical interface is FE i.e. 100 Mbps while the traffic is around 2.5 Mbps.

You can open the attachment by clicking the arrow key pointing downwards.

Regards,

waridtel.com Sat, 09/05/2009 - 03:24

Hi,

Please help me out with this. I am facing severe issues because of this problem.

Regards,

Mohamed Sobair Sat, 09/05/2009 - 04:32

Hi,

This could be due to IP Fragmentation issue.

I would set it as follows:

1- remove the (IP MTU 1400) command from the tunnel interface.

2- configure (Tunnel path MTU discovery) command on both tunnel interfaces.

3- On the Physical interface try to drop the IP MTU to 1476 as the GRE tunnel would add 20 Byte for the IP header and 4 Byte GRE header.

let us know the result,

Mohamed

waridtel.com Sat, 09/05/2009 - 04:54

Hi,

Thanks for your reply.

As per your suggestion I should:

1) remove ip mtu 1400 command from tunnel interface

2) configure "tunnel path mtu discovery" on the tunnel interfaces.

3)On the physical interface I should write the command "ip mtu 1476"

Please confirm me. Thanks.

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