2.7 KiB
Data packet
A data packet contains user specified data. This can be any data, as long as the sender and receiver
both understand what it is, without further help. Intermediate hops, which route the data have sufficient
information with the header to know where to forward the packet. In practice, the data will be encrypted
to avoid eavesdropping by intermediate hops.
Packet header
The packet header has a fixed size of 36 bytes, with the following layout:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Source IP +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Destination IP +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The first 2 bytes are used to specify the length of the body. In practice, packets should be limited to at most the MTU size of the NIC used. This means that the leading bits should be unused. In the future, the protocol might be extended to take advantage of these unused bits.
The next 2 bytes are reserved for future use and should be set to all 0.
The next 16 bytes contain the sender IP address.
The final 16 bytes contain the destination IP address.
Body
Following the header is a variable length body. The protocol does not have any requirements for the body, and the only requirement imposed is that the body is as long as specified in the header length field. It is technically legal according to the protocol to transmit a data packet without a body, i.e. a body length of 0. This is useless however, as there will not be any data to interpret.