ff ff ff ff   ff ff ff ff   ff ff ff ff   ff ff ff ff   # Marker
00 1d                                                   # Length
01                                                      # Message Type (Open)
04                                                      # BGP Version
10 20                                                   # Autonomous System
00 03                                                   # Hold Time
01 02 03 04                                             # BGP Identifier
03                                                      # Opt Parameter Len (too long)

