[ovs-dev] [PATCH 2/2] FAQ: Add additional entries.

[Justin Pettit]

This is great, Ben.  I pushed it with your suggestions.  Thanks.

--Justin


On Jun 20, 2012, at 10:02 AM, Ben Pfaff wrote:

> On Tue, Jun 19, 2012 at 05:08:42PM -0700, Justin Pettit wrote:
>> +Q: What features are not available in the Open vSwitch kernel datapath
>> +   that ships as part of the upstream Linux kernel?
>> +
>> +A: To avoid duplicating functionality in the kernel, certain features of
>> +   Open vSwitch were left out of the upstream version.  This includes
>> +   bridge compatibility, which makes Open vSwitch work with the bridge
>> +   utilities and exports many of its external interfaces.
>> +
>> +   Additionally, dynamic tunneling support is not included.  It is
>> +   possible to create tunnels in Linux and attach them to Open vSwitch
>> +   as system devices.  However, they cannot be dynamically created
>> +   through the OVSDB protocol or set the tunnel ids as a flow action.
> 
> Hmm.  I think we could be more specific:
> 
> A: The kernel module in upstream Linux 3.3 and later does not include
>   the following features:
> 
>       - Bridge compatibility, that is, support for the ovs-brcompatd
>         daemon that (if you enable it) lets "brctl" and other Linux
>         bridge tools transparently work with Open vSwitch instead.
> 
>         We do not expect bridge compatibility to ever be available in
>         upstream Linux.  If you need bridge compatibility, use the
>         kernel module from the Open vSwitch distribution instead of the
>         upstream Linux kernel module.
> 
>       - Tunnel and patch virtual ports, that is, interfaces with type
>         "gre", "ipsec_gre", "capwap", or "patch".  It is possible to
>         create tunnels in Linux and attach them to Open vSwitch as
>         system devices.  However, they cannot be dynamically created
>         through the OVSDB protocol or set the tunnel ids as a flow
>         action.
> 
>         Work is in progress in adding these features to the upstream
>         Linux version of the Open vSwitch kernel module.  For now, if
>         you need these features, use the kernel module from the Open
>         vSwitch distribution instead of the upstream Linux kernel
>         module.
> 
>> +Q: What features are not available when using the userspace datapath?
>> +
>> +A: Similar to the upstream kernel datapath, dynamic tunneling is not
>> +   supported.  It is also not possible to use queue-related actions.
>> +   On older Linux kernels, maximum-sized VLAN packets may not be
>> +   transmitted.
> 
> How about:
> 
> A: Tunnel and patch virtual ports are not supported, as described in the
>   previous answer.  It is also not possible to use queue-related
>   actions.  On Linux kernels before 2.6.39, maximum-sized VLAN packets
>   may not be transmitted.
> 
> Thanks,
> 
> Ben.