This invention is applicable to a Virtual Private LAN service built using
multiple point-to-point Ethernet services from a network operator, where
the bridging and the transport/tunneling of Ethernet frames to a remote
site are decoupled. The learning bridge function (including MAC address
learning and flooding) is performed at customer equipment CE devices,
while the tunneling is performed at provider edge PE nodes. The models
described here for this VPN refer to hub redundancy, site-to-site SLA
guarantees and address discovery in the case of hybrid connections.