Dark Integers: General Purpose Computations on Internet Routers Greg Egan in his fiction "Dark Integers" (story about two universes with two different mathematics communicating by means of proving theorems around of inconsistence in arithmetic) claims that it is possible to build general purpose computer solely on existing internet routers using only its basic functionality of packet switching (and checksum correction, to be precise).

Is this possible, in principle?

Update.

To make the question more precise:

What is an absolutely minimal set(s) of properties the router network must have that it will be possible to build general purpose computer on top of it?
This can be helpful:

Parasitic computing is an example of a potential technology that could be viewed simultaneously as a threat or healthy addition to the online universe. On the Internet, reliable communication is guaranteed by a standard set of protocols, used by all computers. These protocols can be exploited to compute with the communication infrastructure, transforming the Internet into a distributed computer in which servers unwittingly perform computation on behalf of a remote node. In this model, one machine forces target computers to solve a piece of a complex computational problem merely by engaging them in standard communication.

In the parasitic computing site you can detailed information on how you can solve a 3-SAT problem using the checksum of TCP packets.

Other useful links:


Seminar report on parasitic computing by K.K.Maharana
Nature's article on parasitic computing (Aug 2001)