Reading for Lecture Nov 18

An Architecture for Internet Data Transfer

This architecture separates content negotiation from the data transfer. Application determines what data they need to send and then uses the new transfer service to send it. Historically, data transfers have been tightly linked with content negotiation because of TCP and the socket API provide a good enough mechanism and the challenged of naming objects as well.

The benefits of this mechanism is that the developers can reuse transfer technique instead of re-implementing them. Furthermore, applications that use the transfer service can immediately begin using the new transfer techniques without modification. The three main challenges of moving data into a new service are: 1) Providing a convenient and standard API for data transfer applications. 2) Allowing easy development and deployment of new transfer mechanisms. 3) Supporting applications with diverse negotiation and naming conventions.

The DOT service provides three properties: 1) Surviving transient disconnection and mobility. 2) Transferring via portable storage. 3) Using caching and multiple sources. The GTC splits objects into a series of chunks. Each chunk is named with a descriptor containing the hash of the chunk, it length and its offset into object. In DOT, hints are used to inform the receiver’s GTC of possible data locations.

A Delay-Tolerant Network Architecture for Challenged Internets

Today’s Internet may operate poorly in environments characterized by very long delay paths and frequent network partitions. In mobile and extreme environments lacking continuous connectivity, many such networks have their own specialize protocols, and do not use IP.

The DTN architecture is proposed to provide interoperability between them. The architecture operates as an overlay above the transport layers of the networks it interconnects. DTN is based on abstraction message switching. It provides flexible naming scheme in a form of late binding.

The challenged internetworkings are characterized by latency, bandwidth limitations, error probability, node longevity, or path stability that substantial worse than today’s Internet.