Thursday, October 8, 2009


A layer-2 network switch device forwarding database implementation and method to access the forwarding database. A forwarding database (FDB) is implemented as a tree. A separate VLAN database is also structured as a tree. Each node in the tree represents a separate VLAN. For each VLAN, all associated ports are maintained in a data structure organized as a tree. Likewise, all port information is maintained in a tree-based data structure, and for each port, all VLAN information associated with the port is maintained in a tree data structure. Each node in a VLAN's port tree data structure is linked with each corresponding node in the port's VLAN tree data structure. Each pair of nodes maintains a linked list of all FDB entries relating to the node pair. Operations are quickly and efficiently performed on the FDB using the data structure architecture.