Method for establishing restricted broadcast groups in a switched network

A method of forwarding broadcast data packets in a switched data communications network, the network including a plurality of end systems and switches connected by links, the switches having access ports connected to end systems and network ports connected to other switches, and each end system having a unique physical address, the method comprising the steps of:

• a. assigning different virtual LAN identifiers (VLAN-IDs) to different subsets of associated end systems or access ports;
• b. maintaining a first table for mapping the VLAN-IDs to the associated end systems or access ports;
• c. maintaining a second table for mapping the access ports to the associated VLAN-IDs;
• d. when a broadcast packet is received from a source end system at a receiving access port of a first switch:
• i) reviewing the first table for one or more VLAN-IDs associated with the source end system or receiving access port;
• ii) encapsulating the packet by adding a header with the associated VLAN-IDs;
• iii) forwarding the encapsulated packet to all other switches in the network;
• iv) reviewing the second table for the access ports on the first switch associated with the associated VLAN-IDs and forwarding the broadcast packet out the associated access ports;
• and
• e. when the encapsulated packet is received at a next switch:
• i) stripping the header from the encapsulated packet and determining the associated VLAN-IDs;
• ii) reviewing the second table for the access ports associated with the associated VLAN-IDs;
• and
• iii) forwarding the broadcast packet out the associated access ports.