Method for realizing muti-casting in BGP/MPLS VPN

Abstract

The invention discloses a method for realizing multicast in BGP / MPLS VPN. The method comprises: A. discovering all service provider edge routers PE belonging to the same multicast virtual private network MVPN; Unidirectional virtual circuit VC, the VC established between each pair of PEs is bound together to form a fully interconnected bidirectional PW, which is connected to the multicast virtual routing and forwarding table MVRF corresponding to the MVPN on both ends of the PE , the VC label assigned by any PE to other PEs in the MVPN is locally unique; C. When the multicast packet in the MVPN traverses the multi-protocol label switching / Internet Protocol MPLS / IP network of the service provider, the ingress PE will multicast The packet is forwarded to the egress PE through the PW bound to the MVRF, and the egress PE that receives the multicast packet determines the MVRF to which the multicast packet belongs according to the PW that received the multicast packet, and forwards the multicast packet through the MVRF.

Description

technical field [0001] The invention relates to the field of border gateway protocol / multi-protocol label switching virtual private network (BGP / MPLSVPN), in particular to a method for realizing multicast in BGP / MPLS VPN. Background technique [0002] RFC2547 defines the method of establishing a virtual private network (VPN) in a multi-protocol label switching / Internet Protocol (MPLS / IP) network, that is, BGP / MPLS VPN, but RFC2547 only defines the implementation method of unicast IP VPN, and does not define How to implement multicast in BGP / MPLS VPN, that is, MVPN (Multicast VPN). Hereinafter, the VPN supporting multicast is referred to as MVPN for short. [0003] In order to realize multicast in BGP / MPLS VPN, a multicast domain (MD) method has appeared. The basic realization principle of this method is: deploy protocol independent multicast (PIM ) protocol, and assign a unique multicast IP address within the P network range to each multicast virtual private network (MVPN)...

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Problems solved by technology

[0006] Second, the GRE encapsulation and decapsulation process needs to be processed by a network processor (NP), which not only increases the cost of PE equipment but also causes a bottleneck in the multicast forwarding performance within the MVPN

[0007] Third, although Multi-Protocol Label Switching (MPLS) is deployed in the P network, when the multicast packets in the MVPN traverse the P network, they cannot be forwarded on the MPLS Label Switching Path (LSP), but through the multicast IP Address addressing is used for forwarding, so various features bound on the LSP, such as traffic engineering (TE), reliable quality of service (QoS) or fast convergence, cannot be inherited by multicast packets forwarded in the MVPN

In this way, although the on-demand distribution of multicast data packets in the MVPN is realized, the P network needs to maintain a large number of DATA MDTs, and the number of DATA MDTs is not easy to control

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