ff ff ff ff   ff ff ff ff   ff ff ff ff   ff ff ff ff   # Marker
00 31                                                   # Length
01                                                      # Message Type (Open)
04                                                      # BGP Version
10 20                                                   # Autonomous System
00 03                                                   # Hold Time
01 02 03 04                                             # BGP Identifier
14                                                      # Opt Parameter Len
02                                                      # Capability Option
02                                                      # Capability Length
02 00                                                   # Route Refresh Capability, 0 Length
02                                                      # Capability Option
06                                                      # Capability Length
41                                                      # ASN32 Capability
04                                                      # ASN32 Capability Length
12 34 56 78                                             # ASN32 0x12345678
02                                                      # Capability Option
06                                                      # Capability Length
01                                                      # MPBGP Capability
04                                                      # MPBGP Capability Length
00 01 00 01                                             # IPv4, Reserved, Unicast

