-- binary
04 12 # version, type
00 18 # length
11 11 11 11 # xid
ff ff # stats_type
00 00 # flags
00 00 00 00 # pad
FF 00 00 07 # experimenter
00 00 00 01 # subtype

-- python
ofp.message.exp_port_desc_request(
    xid=0x111111)