MAC Address Translation for Enabling Scalable Virtual Private LAN Services

Virtual private LAN service (VPLS) has been considered as a feasible solution for transparent LAN service. By virtually locating all of the service intelligence in the provider edge routers, the VPLS architecture can be easily integrated with the existing IP/MPLS networks. Nevertheless, the VPLS architecture has scalability issues, such as signaling for full-mesh connectivity, replication and media address control (MAC) address table explosion. While the first two can be tackled by hierarchical VPLS, the existing solution for the last problem involves the layer-3 routers and changes the original form of layer-2 VPN. In this paper, we present a MAC address translation scheme to achieve scalable VPLS. Our scheme is based on the "locally administered address", which is defined in the Ethernet specification. The proposed scheme can significantly reduce the size of MAC address tables from N times M entries to N + M(M - 1) entries for each VPLS instance, where N and M are the numbers of the hosts and sites respectively.