The IPv4 Multicast Option or IPv6 Multicast Option are used by the server to announce the IPv4 or IPv6 multicast address, the transport layer protocol (ISO/OSI layer 4), and the port number the multicast events and multicast notification events are sent to. 服务器使用IPv4 Multicast Option或者IPv6 Multicast Option来分别通知IPv4或IPv6多播地址，传输层协议（ISO / OSI第4层）和端口号，用来作为发送多播Event和多播notification event的目的地址。
As transport layer protocol, only UDP is supported. 作为传输层协议，仅支持UDP。
IPv4 Multicast Options shall be only referenced by SubscribeAck entries, describing the multicast destination IP address and port multicast events shall be sent to. IPv4 Multicast Options只能由SubscribeAck entry引用，描述发送多播Event的目的地IP地址和端口。
The Port Number field [16 bits] of the IPv4 Multicast Option Options shall carry the port number for transporting Multicast Events of the Eventgroup. IPv4 Multicast Option的Port Number字段[16位]应携带用于传输Eventgroup的多播Event的端口号。
