Fig. 1. The BIER multicast communication process in SDN

Fig. 2. The change of SI with edge nodes in SD (BSL=2)

Fig. 3. An example of three-tiered HD-BIER (BSL=3)

Fig. 4. The topology of the experimental network

Fig. 5. Effectiveness of HD algorithm (different colors represent different BIER SD)

Fig. 6. The topology of the simulation network

Fig. 7. HD-BIER multicast communication

Fig. 8. The flow entry and group entry of switch S₁₂

Fig. 9. The flow entries of switches connected to multicast receivers

Fig. 10. The BitString changes during HD-BIER multicast communication

Fig. 11. Delay in joining a multicast group