1. A method of forwarding packets in a communication system having multiple incoming service interfaces and multiple output service interfaces for providing service to multiple distinct and isolated user networks, said method comprising: providing at least one route server to compute forwarding rules based on routing topology and policing information relevant to each of said distinct and isolated user networks; providing edge forwarders for terminating said incoming service interfaces and for forwarding received packets, said forwarders relying for routing services on forwarding information received from said at least one route server; transferring said computed forwarding rules from said at least one route server to said edge forwarders; receiving said packets at one of said incoming service interfaces; selecting an appropriate forwarding rule based on a source address in said packets and on the incoming service interface from which the packets are received; and the corresponding edge forwarder for said one incoming service interface forwarding said packets to one of said output service interfaces, the decision as to which output service interface to forward the packets to being based on a destination address in said packets and information in said selected forwarding rule.