Re: OpenFlow version hell

[Anil Madhavapeddy <anil@xxxxxxxxxx>]

Thanks for this summary, Prashanth.  I looked around for 1.3 implementations,
and came up with just this switch:
https://github.com/CPqD/ofsoftswitch13

This does convince me that having continuing to develop the controller and
switch library would very useful, since we could use it to mix-and-match
different deployment scenarios, but also understand the performance impact
of different data structures for use within the switch itself...

-anil

On 30 Apr 2013, at 18:21, Prashanth Mundkur <pmundkur.ocaml@xxxxxxxxx> wrote:

> 
> As mentioned on today's Mirage call, here are some pointers to
> OpenFlow versioning issues.
> 
> https://github.com/horms/openvswitch/blob/master/OPENFLOW-1.1%2B#L38
> 
> This document underplays the issues, especially for OpenFlow 1.1.
> There are major changes in the semantics for flow matching.
> 
> - Wildcards vs. exact matching
> 
> https://www.opennetworking.org/images/stories/downloads/sdn-resources/onf-specifications/openflow/openflow-spec-v1.0.0.pdf
> OF 1.0, Section 3.4:
> 
>  Packets are matched against flow entries based on prioritization. An
>  entry that specifies an exact match (i.e., it has no wildcards) is
>  always the highest priority.  All wildcard entries have a priority
>  associated with them. Higher priority entries must match before
>  lower priority ones.
> 
> https://www.opennetworking.org/images/stories/downloads/sdn-resources/onf-specifications/openflow/openflow-spec-v1.3.1.pdf
> OF 1.3.1, Section 5.3:
> 
> The packet is matched against the table and only the highest priority
> flow entry that matches the packet must be selected.
> 
> (The language is a little more ambiguous in OF 1.1, but the intent is
> clarified in 1.3.1 above.
> 
> https://www.opennetworking.org/images/stories/downloads/sdn-resources/onf-specifications/openflow/openflow-spec-v1.1.0.pdf
> Section OF 1.1, Section 4.4:
> 
>   The switch should apply the instruction set and update the
>   associated counters of only the highest-priority flow entry
>   matching the packet.
> )
> 
> - VLAN tag matching
> 
> Summarized here:
> 
> https://github.com/horms/openvswitch/blob/master/DESIGN#L155
> 
> --prashanth
>