Hypermedia - Data Submodel Nodes are the primitive unit for organising information in hypermedia network. Nodes function as collections of primitive unstructured data which are bind together in order to create one logical entity. The purpose of this logical entity should be to provide a coherent information abstraction to existing information space. For example, in a hypermedia system about the Aristotle's life, a node can combine a text description, a sound information, a graphics picture and a digital video about the Aristotle's birthplace, Stagyra. Links are the other fundamental units of data submodel.
Links implement the directed interconnections between nodes.
They are Anchor ed to a departure node and provide the hypermedia user the ability to activate them and move to the destination node. Links are associated with parts of departure nodes rather than with the node as a whole. This is less frequently for associations between links and destination nodes. But, since most of hypermedia systems don't support bi-directional links we can not assume undirected links as part of the basic hypermedia model. Figure 1 shows a graphical representation of a simple hypermedia information network consisting of five nodes and several directed links between nodes.