Design

The basic building block for nt is IP multicast [#!deer:88!#][#!mac:94!#]. This provides us with many-to-many communication at constant cost, irrespective of the number of receivers. To achieve resilience, we adopt a distributed, replicated data model, with every participant attempting to hold a copy of the entire document being shared. This means that end-systems or links can fail, but that the remaining communicating sites still have sufficient data to continue if they desire to do so. Updates to the distributed data model are made using IP multicast, although this means that due to packet loss, not all sites will receive a particular update - how this is resolved is discussed later.

In designing nt, we attempted to apply the guiding principle of application level framing (ALF, [#!ddc:91!#]) - thus the application and its communication model employ the same data units.