Patent ID: 8027454

Claim:
A method of reserving trunks on a first trunk group for calls comprising: denominating a plurality of classes of service wherein the classes have priorities allowing a class to act as a super class or subclass of a different class for trunk allocation purposes, specifying a number of trunks available for at least one of the denominated classes of service, enumerating a number of trunks remaining and designating them as of no class and available for all calls; wherein when the trunks of no class are all in use: and where a new call is of a denominated class of service; allocating the new call to a trunk of the denominated class of service and reducing the trunks available for that class of service by one, otherwise allocating the new call to a further trunk group; and when a call is released, and the number of trunks available to a class of service associated with the call is reduced below a specified number, increasing the number of available trunks for that class of service; otherwise making a trunk associated with the released call available for all calls.