The Hy+ system ([Cons93]) was developed by researchers at the University of Toronto. It is designed for the visualization and manipulation of hygraphs. A hygraph is a generalization of a standard graph containing nodes, links, labels and container information. The system incorporates a powerful programming language for the manipulation of these hygraphs, which can be done interactively.
One of the applications of Hy+ has been to that of network visualization. By representing a network of computers as a hygraph they can take advantage of the system's strengths to analyse data about such a network. The power of the programming language on which the system is based, allows a user to develop queries and alarms on the data in the hygraph.
The work of researchers at AT&T's Bell Laboratories ([Beck91],[Beck95]) has been in the area of network visualization using data obtained from AT&T's long distance telecommunications network which connects the larger part of the United States. They have developed several innovative techniques for keeping the display of a complex, heavily connected network uncluttered, while still maintaining geographical accuracy in the layout.
Their system, SeeNet, also makes use of the colour and the magnitude of graphical elements for the display of statistics related to the various links in their network. They also placed emphasis on the connectivity between the various network nodes.
The user interface has also been the subject of research. For example, the bifocal viewing system developed by researchers at NEC ([Fuji94]) allows a user to view a scene at two different levels of magnification. The result of which is a technique, where by a complex network can be displayed and the user can still distinguish detail about the nodes on the network by using the area of higher magnification. It is also possible to move the magnification area over the entire scene in real-time, but to achieve this required dedicated hardware.
What I discovered during my research was that there are many tools for the visualization of networks themselves and their corresponding link utilization and connectivity data. However these tools lack the ability to display general information about the individual nodes. The systems were designed to display specific information related to network information. As stated in the introduction, the goal of NetSpy is to overcome these shortcomings