In a broadband access network multiple end users (10) connected to access nodes (201) are linked to multiple service providers (30) connected to an edge node (202). Packet transmitted across the network contain a quality of service identifier specifying a relative QoS or priority or an absolute QoS, defining minimum quality of service parameters required for handling the packet. The access network is preferably divided into separate virtual local area networks (VLANs) providing separate broadcast domains for the various end users. Each packet transmitted on the access network is VLAN-tagged with QoS identifier contained in this tag. When an access node or edge node receives an incoming data unit that specifies an absolute quality of service, the node determines that there is sufficient bandwidth through the access network to the destination node by querying other nodes in the network directly or indirectly through a bandwidth broker (203) before accepting the service and transmitting the packet.