Packet Formats
The DCCP header can be from 12 to 1020 bytes long. The initial part
of the header has the same semantics for all currently defined packet
types. Following this comes any additional fixed-length fields
required by the packet type, and then a variable-length list of
options. The application data area follows the header. In some
packet types, this area contains data for the application; in other
packet types, its contents are ignored.