1. A method of identifying a connectivity characteristic structure in a trail provided between a plurality of nodes in a network, the method comprising the steps of: acquiring node information detailing for each port of each node of the trail, a connectivity characteristic; collating for at least a plurality of nodes forming the trail in said network each nodes respective acquired node information to form a set of connectivity characteristics for the trail; and analysing said set of connectivity characteristics to determine a set of at least one rule for the trail describing a connectivity characteristic structure of said plurality of nodes.