On Wed, Sep 21, 2016 at 05:20:28PM -0700, Ray Li wrote:
> Is there anyway to specify other action types for a learn rule? For example
> learn(<criterion>,normal) or
> learn(<criterion>,resubmit(,10))

The FAQ says:

### Q: The "learn" action can't learn the action I want, can you improve it?

A: By itself, the "learn" action can only put two kinds of actions
   into the flows that it creates: "load" and "output" actions.  If
   "learn" is used in isolation, these are severe limits.

   However, "learn" is not meant to be used in isolation.  It is a
   primitive meant to be used together with other Open vSwitch
   features to accomplish a task.  Its existing features are enough to
   accomplish most tasks.

   Here is an outline of a typical pipeline structure that allows for
   versatile behavior using "learn":

     - Flows in table A contain a "learn" action, that populates flows
       in table L, that use a "load" action to populate register R
       with information about what was learned.

     - Flows in table B contain two sequential resubmit actions: one
       to table L and another one to table B+1.

     - Flows in table B+1 match on register R and act differently
       depending on what the flows in table L loaded into it.

   This approach can be used to implement many "learn"-based features.
   For example:

     - Resubmit to a table selected based on learned information, e.g. see:

     - MAC learning in the middle of a pipeline, as described in

     - TCP state based firewalling, by learning outgoing connections
       based on SYN packets and matching them up with incoming

     - At least some of the features described in T. A. Hoff,
       "Extending Open vSwitch to Facilitate Creation of Stateful SDN
discuss mailing list

Reply via email to