Name of the type - will almost certainly not be unique How many virtual nodes of this type this physical node can handle. element unlimited { empty }?, A flag that indicates that this physical node *always* has this type - a node is only allowed to have one dynamic (ie. not flagged as static) type at a time, but any number of static types at a time element static { empty }? Link types are currently just a siple string. They will almost certainly have to get more complicated, for two reasons: First, I want to allow virtual links to specify more than one type, so that we can ask for links that are, say, 'ethernet or loopback' Second, I want to have a lot more control over links that get mapped to multi-hop paths TODO: MAYBE this should be combined with NodeTypeSpec A link has two endpoints. Right now, they are order independent. But they might become order-dependant later. First interface for this link Second interface for this link Link characterstics which affect traffic. TODO: In the future, the bandwidth, latency, and packet loss will be moved to features and/or properties Name of this feature or desire element fd_name { text }, Weight assocated with the feature or desire element fd_weight { xsd:float }, A flag indicating whether or not a failure to match the desire with a a feature is a constraint violation element violatable { empty }?, GlobalSpec = element global { element operator { "OnceOnly" | "FirstFree" } } LocalSpec = element local { element operator { "+" } attribute local_operator { "+" } } Interfaces InterfaceSpec = element interface { InterfaceContents } Properties of the interface Name of the node, which must match one of the nodes in this topology Name of the interface itself Name of this property Value associated with this property TODO: Add ranges and other types from rspec The penalty associated with this property If this flag is present, not having the property is considered a violation