A BGP (Border Gateway Protocol, border gateway protocol) is an exterior gateway protocol for communication between different autonomous systems. A BGP-based MPLS (Multi Protocol Label Switching, multi protocol label switching) IP (Internet Protocol, Internet Protocol) VPN (Virtual Private Network, virtual private network) is generally called an L3VPN (Level3 VPN, Level 3 virtual private network). In the L3VPN, a RD (Route Distinguisher, route distinguisher RD) is generally used to distinguish overlapping VPN route prefixes in different VPNs, and an RT (Route Target) is used to identify a VPN membership.
In an existing L3VPN, when publishing VPN routing information by using the BGP, a local PE (Provider Edge, provider edge) allocates a specific VPN label to a VPN route prefix belonging to a specific VPN and publishes the VPN label to all remote PEs belonging to a same VPN. In this way, when forwarding packets to the local PE, the remote PEs belonging to the same VPN all carry a same VPN label. A BGP/MPLS L3VPN needs to use an MPLS tunnel for bearing. When an LSP (Label Switching Path, label switching path) established by using an LDP (Label Distribution Protocol, label distribution protocol) is used to bear the L3VPN, because the LDP LSP belongs to a multi-point to point type, that is, an egress node (Egress) of the LSP cannot determine a source of a packet according to an LSP tunnel label, and packets sent by different remote PEs carry a same VPN label, consequently the local PE cannot distinguish the packets from the different remote PEs. For fault management and performance measurement of the L3VPN, two ends for sending and receiving a packet need to be determined; therefore, in this case, fault management and performance measurement of the L3VPN cannot be implemented.
USPTO Backgrounds
USPTO Backgrounds