A simple extension mechanism. Most entities can have locally understood attributes attached. An indication of how requested networking capacity is measured. This will undoubtably expand. A strawman network capacity description for access negotiation. This will come to include more and more interesting parameters. Rate in kb/s. A strawman network latency description for access negotiation. This will come to include more and more interesting parameters. Time is in msec. Description of media through which elements can communicate The CPU requirements of a computer or other entity. The type is a string for simplicity. We may make this more complex later. Description of how long storage is available The storage requirements of a computer or other entity. The amount and its persistance. Amounts are in megabytes. Should media be requires, an attribute can be used. The OS requirements of a computer or other element with an OS. An piece of software and where to install it on an element. Some distribution types have the install location embedded in the format, and for them the installation location is empty. An interface to at least one communication substrate. Details like address assignement are in attributes. A general purpose computer as part of a topology. A testbed is an abstract resource collection. A collection of resources instantiated on a testbed An element described only by attributes. An element in the topology to be created. Description of an experimental topology for the federant to create.