[ovs-dev] [bfd] bfd: Implement Bidirectional Forwarding Detection.

[Ethan Jackson]

Yep this all seems reasonable to me, however I don't think it should
be done specifically for BFD.  Instead we should do it for all
protocols (CFM LACP BFD) which have something to say about the
liveness of a link.  That said,  I don't intend to put time into this
at the moment.  Feel free to submit a patch if you think it's
important.

Thanks,
Ethan

On Wed, May 8, 2013 at 9:46 AM, Ben Pfaff <blp at nicira.com> wrote:
> On Wed, May 08, 2013 at 05:48:52AM +0000, Rajahalme, Jarno (NSN - FI/Espoo) wrote:
>> Ethan,
>>
>> Looking at the code, it seems to me that there is no link from BFD
>> to OpenFlow PORT_STATUS message. I might be wrong, but it seems
>> possible that BFD indicated port state changes could be communicated
>> to the controller with the OFPPS_LIVE (= OFPUTIL_PS_LIVE) status
>> bit, using the ofproto_port_set_state() function.
>>
>> This from the OpenFlow 1.3.1 spec:
>>
>> "- A port is considered live if it has the OFPPS_LIVE flag set in
>> its port state. Port liveness may be managed by code outside of the
>> OpenFlow portion of a switch, defined outside of the OpenFlow spec
>> (such as Spanning Tree or a KeepAlive mechanism). At a minimum, the
>> port should not be considered live if the port config bit
>> OFPPC_PORT_DOWN indicates the port is down, or if the port state bit
>> OFPPS_LINK_DOWN indicates the link is down."
>>
>> OFPPS_LIVE is specified for OF1.1+ with a comment "Live for Fast
>> Failover Group", but I don't see why the bit could not be used also
>> without any failover groups. Thoughts?
>
> Seems reasonable to me at first glance.  But I guess we'd also want to
> link it to CFM?