ff ff ff ff   ff ff ff ff   ff ff ff ff   ff ff ff ff   # Marker
00 1f                                                   # Length
01                                                      # Message Type (Open)
04                                                      # BGP Version
10 20                                                   # Autonomous System
00 03                                                   # Hold Time
01 02 03 04                                             # BGP Identifier
01                                                      # Opt Parameter Len (invalid)
F0 00                                                   # Option with no data

