The Physical Package Protocol is being designed to bring the benefits of Data Packet Switching to physical packages.  This will enable a system where all packages, not just the most urgent and most expensive, to be freed from large centralised sorting offices and daily delivery rounds. 

For over a hundred years all wired communication was carried over dedicated point to point lines (telegraph system) or over circuit switched lines (telephony).  In Circuit Switched systems switches within the telephone exchanges create a continuous wire circuit between two telephones which is maintained for as long as the call lasts.  This was never very efficient and the only way to provide more connections was to string more lines, one new line per extra call capacity.

Now almost all information in wired communication (including all voice calls) is carried over networks of routers in network packets.  A packet is a small unit of data with an Internet Protocol number attached, carried by a packet-switched network until it reaches the computer with that Internet Protocol address.  When data is formatted into packets, the bandwidth of the communication medium can be better shared among users than if the network were circuit switched. 

Our existing letter and package delivery networks relies on principles similar to Circuit Switched networks. Items are collected once daily from post boxes, they are taken to large sorting offices, then taken by dedicated trucks to be delivered by a person driving or walking a route which takes them to each location once per day.  

The Physical Package Protocol will allow packages travelling short distances to be delivered as quickly as the network will allow, sometimes within minutes, removing the need for packages to travel to a centralised location.  Packages traveling longer distances will be carried by Mules, eg. buses, trains, trucks ferries, self driving vehicles, etc.  This means that the "bandwidth" of the system can be shared among all the users of the existing tranport infrastructure and can scale up much more efficiently.

Packages will be carried or "switched" between different Physical Package Routers and Mules by autonomous drones, either ground/aerial hybrid systems or entirely aerial based.  These will be known as Pigeons and will be the "dumb wires" of the system only delivering packages where and when directed to by the Package Routers.

Another great advantage of the Physical Package Protocol is that Packages can be switched to arrive where the intended recipient actually is, not just their home or office address.  At present this can only be achieved using an expensive dedicated system such as cycle dispatch riders, which do not sit within the existing postal networks.

Let’s think big! Public Transport infrastructure in a city could be entirely replaced with a Packet Switched based system if passengers are treated as Packets. Each person can choose their destination and set their desired Target Arrival Time, Comfort Level and Price on a municipal licenced phone app. Then all the robot taxi companies in the area can bid to fulfil either the whole or part of the journey.
— Nathan Rae