  A fundamental problem faced in the design of almost all packet networks is
that of efficient operation--of reliably communicating given messages among
nodes at minimum cost in resource usage. We present a solution to the efficient
operation problem for coded packet networks, i.e., packet networks where the
contents of outgoing packets are arbitrary, causal functions of the contents of
received packets. Such networks are in contrast to conventional, routed packet
networks, where outgoing packets are restricted to being copies of received
packets and where reliability is provided by the use of retransmissions.
  This thesis introduces four considerations to coded packet networks: 1.
efficiency, 2. the lack of synchronization in packet networks, 3. the
possibility of broadcast links, and 4. packet loss. We take these
considerations and give a prescription for operation that is novel and general,
yet simple, useful, and extensible.
