MVPN Traffic Forwarding Through NG MVPN over BIER

After a multicast receiver joins a multicast group, the multicast source can send MVPN traffic to the multicast receiver over an established public network PMSI tunnel.

Figure 1 Typical NG MVPN over BIER scenario
Click to enlarge

Figure 2 MVPN traffic forwarding through NG MVPN over BIER
Click to enlarge

Table 1 describes how MVPN traffic is transmitted through NG MVPN over BIER.

**Table 1** Process of MVPN traffic forwarding through NG MVPN over BIER
Step	Device Name	Action	Multicast Forwarding Table
1	CE1	After receiving an IP multicast packet from the multicast source, CE1 searches its multicast forwarding table and forwards the packet to PE1.
2	PE1	After receiving the MVPN packet, PE1 searches its VPN instance multicast forwarding table for the corresponding (C-S, C-G) entry, adds a BIER header to the packet, and sends the packet to the P based on the BIER MPLS label information.
3	P	After receiving the packet with the BIER header, the P replicates the packet, re-encapsulates the copy of the packet with a new BIER header, and then forwards the packet copy according to the BIER forwarding table.	-
4	PE2/PE3	After receiving the packet copy with the BIER header, PE2/PE3 finds that the bit position in the BitString indicates itself. Therefore, PE2/PE3 removes the BIER header, searches the multicast forwarding table of the corresponding VPN instance for the (C-S, C-G) MVPN multicast forwarding entry, and forwards the packet copy to CE2/CE3.
5	CE2/CE3	After receiving the packet copy, CE2/CE3 searches its multicast forwarding table and forwards the packet copy to all receivers in the multicast group.