Composite Names and Contexts

Fundamental to FNS are the notions of composite names and contexts.

Composite Names

A composite name is a name that spans multiple naming systems.

A composite name consists of an ordered list of components. Each component is a name from the namespace of a single naming system. Individual naming systems are responsible for the syntax of each component. FNS defines the syntax for constructing a composite name using names from component naming systems. Composite names are composed left to right using the slash character (/) as the component separator.

For example, the composite name .../doc.com/site/bldg-5.alameda consists of four components: ..., doc.com, site, and bldg-5.alameda.

Contexts

A context provides operations for:

• Associating (binding) names to objects

• Resolving names to objects

• Removing bindings

• Listing names

• Renaming

• Associating attributes with named objects

• Retrieving and updating attributes associated with named objects

• Searching for objects using attributes

A context contains a set of name-to-reference bindings. Each reference contains a list of communication end-points or addresses. The federated naming system is formed by contexts from one naming system being bound in the contexts of another naming system. Resolution of a composite name proceeds from contexts within one naming system to those in the next until the name is resolved.

Attributes

Attributes may be applied to named objects. Attributes are optional. A named object can have no attributes, one attribute, or multiple attributes.

Each attribute has a unique attribute identifier, an attribute syntax, and a set of zero or more distinct attribute values.

XFN defines the base attribute interface for examining and modifying the values of attributes associated with existing named objects. These objects can be contexts or any other types of objects. Associated with a context are syntax attributes that describe how the context parses compound names.

The extended attribute interface contains operations that search for specific attributes and that create objects and their associated attributes.