| 摘要 |
<p>The present invention discloses a 3-layer Virtual Private Network (VPN) which comprises P devices and PE devices in the backbone network, a plurality of sites and CE devices in subscribers' VPNs, and Hierarchy of PE (HoPE) devices, said HoPE devices serve as edge routers in the backbone network and are connected to P devices in the backbone network as well as sites and CE devices in subscribers' VPNs; said HoPE devices comprise understratum PEs (UPEs), zero or more middle-level PEs (MPEs) and superior PEs (SPEs) connected with each other, and all of said PEs (UPEs, MPEs, and SPEs) take different roles and deliver the function of a central PE. For the SPEs, the routing and forwarding performance should be relatively higher; while for UPEs, the performance may be lower. The architecture according to the present invention can enhance the expandability in hierarchical BGP/MPLS VPNs. <IMAGE></p> |
