[pve-devel] Process to submit patches

Andrew Thrift andrew at networklabs.co.nz
Wed Apr 17 23:55:27 CEST 2013

Hi Dietmar,

We have been running this successfully for a few weeks now on the 
default PVE kernel with no issues.

I searched the list archives, and the issues I could see looked like 
they were related to the MTU on the parent physical interface being too 

Linux does not clearly differentiate between L2 (interface) and L3 (IP) 
MTU, and also has a hidden 4 byte allowance on the interface MTU, making 
it confusing.  When running QinQ the parent physical interface needs a 
MTU of at least 1504 bytes (allows a 1508 byte frame), any sub vlan's 
and bridges will then inherit this MTU allowing for the "inner" tag to 
pass externally correctly.

Obviously if the users are not doing QinQ the parent physical interface 
can be the default 1500byte MTU and will work perfectly.

We have only tested with KVM, so maybe there are other issues with 
OpenVZ...   If there are not, it would be good to see this patch merged.



On 4/2/2013 5:32 PM, Dietmar Maurer wrote:
>> Our patches creates the vlan sub-if on the parent VM bridge, rather than
>> on the parent interface.   This works with both QinQ and non QinQ
>> configurations.
> AFAIR this create serious problem. We already tried that several times and always run
> into problems. Search the list for details.

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