Design And Implement Of Ring Network Multicast Based On PON

The redundant links provided by the ring network improve the reliability of the network.Compared with other network structures,ring network has strong protection capabilities,but this is likely to cause broadcast storms and MAC address drift,resulting in unavailability of network.The Multiple Spanning Tree Protocol(MSTP)Family and the Ethernet Ring Protection Switching(ERPS)can achieve logical destruction in the case of a physical ring and provide redundant backup links.Ring network brings obstacles to multicast-based applications.Internet Group Management Protocol(IGMP)is used to maintain the membership of multicast groups.There are at least two links in the ring network,so the problem of link availability identification needs to be solved to verify the correct reception of multicast data.In this paper,we use C language as the development language,briefly introduces the ring network structure and ring network protocol: Multiple Spanning Tree Protocol Family and Ethernet Ring Protection Switching,Multicast Principles and Multicast Protocol,and introduces the overall software architecture and design of each unit module in detail,focusing on the design and implementation of multicast under two different ring network protocols:(1)In MSTP ring network multicast,the concept of multicast uplink mode is proposed.When the multicast uplink mode is MSTP,the blocked port in the MSTP protocol does not transmit multicast protocol packets and data packets,ensuring that there is only an available link.When the link fails and recovers,the new root port sends multicast report messages to ensure multicast recovery rapidly.(2)In ERPS ring network multicast,the concept of hybrid port is proposed.When a multicast query message is received,the hybrid port is the multicast uplink port,and the other hybrid port in the ring on the same device is the multicast cascade port.Correctly distinguish the role of the multicast port to ensure normal multicast traffic.After compiling the program,load it on the hardware platform of the Passive Optical Network(PON)with Linux to verify the ring network multicast under the two ring network protocols.The test result shows that the ring network multicast solution is feasible,the MSTP ring network multicast failure switching time is about 1.5s,and the recovery time after the fault is about 500ms;while the ERPS ring network multicast switching time is about 200 ms,the recovery time is about 50 ms,ERPS ring network multicast takes less time than MSTP ring network multicast.