anchor.diff:  [source,yaml]
   ----
     type: FLOW_MOD
  -  version: 1  // <1>
  +  version: 1    # OpenFlow 1.0
     msg:
       cookie: 0
  -    cookie_mask: 0xFFFFFFFFFFFFFFFF   // <2>
  -    table_id: 0  // <2>
  +    cookie_mask: 0xFFFFFFFFFFFFFFFF   # Ignored; not present in OpenFlow 1.0
  +    table_id: 0    # Ignored; not present in OpenFlow 1.0
       command: ADD
       idle_timeout: 10
       hard_timeout: 30
  
positive.code: [source,yaml]
  ----
  type: PACKET_OUT
  version: 4  // <1>
  msg:
    buffer_id: NO_BUFFER
    in_port: CONTROLLER  // <2>
    actions: 
      - action: OUTPUT
        port: 0x11  // <3>
        max_len: MAX
    data: 'ffffffffffff0000000000010800'
  ----
  <1> For version, we use the `wire version`; 4 refers to the 1.3 spec.
  <2> Use strings for special values and flags.
  <3> YAML supports hexadecimal numbers.
  
  The YAML syntax is based on OpenFlow 1.4, but the same input
  can generate earlier protocol version messages. Libofp is intelligent about
  
negative.code:     buffer_id: NO_BUFFER
      out_port: ANY
      out_group: ANY
      flags: [ SEND_FLOW_REM, CHECK_OVERLAP ]   # Flags as array of strings
      match:
        - field: IN_PORT
          value: 1
        - field: IPV4_SRC     # Match field dependencies added automatically
          value: '192.168.1.1'
      instructions:
        - instruction: APPLY_ACTIONS
  