[ovs-discuss] Strange value of openflow dpid

[Michael Steiger]

Hello!

I am currently using a hardware switch which is running openvswitch 1.2.2

If I set a new openflow controller using ovs-vsctl set-controller the
connection is instantly available.

What I am wondering though is the value of dpid.

The MAC address of the management interface of the switch is
eth0      Link encap:Ethernet  HWaddr 04:7D:7B:68:7B:C7

But the dpid the controller (floodlight) receives is
DPID[00:00:04:7d:7b:68:7b:c6]

The dpid is always exactly minus one of the MAC address.

The OpenFlow 1.0 specification says
"The datapath_id field uniquely identies a datapath. The lower 48 bits
are intended for the switch MAC address, while the top 16 bits are up to
the implementer."


Can anyone please explain this difference?

Thanks
Michael