Routing calls to external networks from a private network

A method of routing calls to an external network from a calling node of a private network having a plurality of external network access circuit groups wherein each access circuit group is connected to a gateway node of said private network, the method comprising:

• calculating a cost for different possible routes to said external network, the cost of a route to said external network being a function of a cost of the access circuit group and a cost of a route in said private network between said calling node and said gateway node of said access circuit group;
• combining the calculated cost of the access circuit group with the cost of the route in said private network between said calling node and said gateway node;
• and
• selecting a route from said calling node to said external network as a function of the calculated combined costs, wherein the cost of the access circuit group includes the type of call to be routed.