Readers are authorized by the owner and the owner is in charge of ensuring coherence of cached lookups through the use of some consistency protocol such as callbacks, leases or the like. Ownership can change hands by passing an encrypted copy of the current directory from one writer to another, updating a location database and forwarding requests from the old owner to the new owner. The delivery system must be able to provide content requested by cfid. There are considerable problems in handling the data location problem. Instead of a the traditional simple and fragile server-centric star topology of servers and clients we would like to support a dynamic hierarchy of caches, replicas, mirrors, archives and the like which provide data by cfid.
Consumers pay for delivered data.
Separating producers and consumers in both time and space, however, are data merchants. They find may it profitable to store popular data, as well as provide data caching or location services. For example, if the primary repository of a very popular file is overloaded it will be advantageous to requesters to turn to secondary sources for the file who can then profit from having kept a copy. Devising algorithms and protocols that allow the delivery system to respond efficiently and quickly to changes in demand while still handling routine access to data across a tremendous range of popularity will be challenging. I think that market-based mechanisms are up to the task.