[ovs-dev] [PATCH 2/9] Fix ovs-ofctl documentation.

[Jarno Rajahalme]

On Oct 17, 2013, at 10:10 AM, Ben Pfaff <blp at nicira.com> wrote:

> On Wed, Oct 16, 2013 at 04:16:04PM -0700, Jarno Rajahalme wrote:
>> Make it clear that match fields are rejected when their prerequisities
>> are not met, rather than just having their values ignored.
> 
> What do mean when you say they're rejected?  Certainly OVS will reject a
> NXM or OXM that matches on, say, IP TTL, if the dl_type doesn't specify
> IP, but ovs-ofctl will in fact just ignore it.  e.g.:
> 
>    blp at blp:~/nicira/ovs/_build(1)$ utilities/ovs-ofctl parse-flow nw_ttl=123,actions=drop
>    2013-10-17T17:08:26Z|00001|ofp_util|INFO|normalization changed ofp_match, details:
>    2013-10-17T17:08:26Z|00002|ofp_util|INFO| pre: nw_ttl=123
>    2013-10-17T17:08:26Z|00003|ofp_util|INFO|post: 
>    usable protocols: NXM,OXM
>    chosen protocol: NXM-table_id
> 

Oops, I was too quick to read output like above as an error condition. I'll update this.

> (Whether that's a good design or not is another question--it's probably
> a bad design, in fact--but it's historical behavior dating back to the
> OpenFlow reference implementation and beyond, and so it's hard to
> change.)
> 
>> Also state that if decrementing makes a TTL zero, the controller
>> notification may be sent.
> 
> I agree with that.