[ovs-discuss] packets getting dropped at egress

[Dave Waters]

Its not. But how do i ensure that my packet does not get dropped somewhere
downstream, since i have now increased it beyond the original value?

On Thu, Jul 23, 2015 at 7:49 PM, gowrishankar <
gowrishankar.m at linux.vnet.ibm.com> wrote:

> On Thursday 23 July 2015 04:16 AM, Dave Waters wrote:
>
>> Hi,
>>
>> I have two ports in my OVS bridge. I receive packets from one port
>> (portA) and i send them out of the other (portB). When i send out the
>> packets, they are VXLAN tunneled to the other end.
>>
>> Now, the default MTU of all ports (including the bridge port) is 1500 in
>> my setup.
>>
>> The issue is that when i get a 1500 byte packet on portA, i try to push
>> it out on portB after slapping on the VXLAN headers. This results in a
>> packet size thats greater than what portB can handle, and hence the packets
>> are dropped.
>>
>>
> Is increasing MTU of portB to 1550 (to accommodate additional 50 bytes
> when no vlan taged) a constraint in your setup ?
>
>
>  I know that OVS does not handle IP fragmentation/reassembly, so how do we
>> deal with this situation? I dont think we can rely on path MTU discovery
>> since not all applications do PMTU before spewing out packets. Any ideas,
>> anybody?
>>
>> Warm regards,
>> Dave
>>
>>
> --
> Regards,
> Gowrishankar M
>
>
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