Operation Manual – Multicast ProtocolH3C S3610&S5510 Series Ethernet Switches Chapter 1 Multicast Overview1-6z Addressing mechanism: Information is sent from a multicast source to a group ofreceivers through a multicast address.z Host registration: Receiver hosts are allowed to join and leave multicast groupsdynamically. This mechanism is the basis for group membership management.z Multicast routing: A multicast distribution tree (namely a forwarding path tree formulticast data on the network) is constructed for delivering multicast data from amulticast source to receivers.z Multicast applications: A software system that supports multicast applications,such as video conferencing, must be installed on multicast sources and receiverhosts, and the TCP/IP stack must support reception and transmission of multicastdata.1.3.1 Multicast AddressesTo allow communication between multicast sources and multicast group members,network-layer multicast addresses, namely, multicast IP addresses must be provided.In addition, a technique must be available to map multicast IP addresses to link-layermulticast MAC addresses.I. IPv4 multicast addressesInternet Assigned Numbers Authority (IANA) assigned the Class D address space(224.0.0.0 to 239.255.255.255) for IPv4 multicast, as shown in Table 1-1.Table 1-1 Class D IP address blocks and descriptionAddress block Description224.0.0.0 to224.0.0.255Reserved multicast addresses (addresses for permanentmulticast groups). The IP address 224.0.0.0 is reserved, andother IP addresses can be used by routing protocols and fortopology searching and protocol maintenance.224.0.1.0 to231.255.255.255233.0.0.0 to238.255.255.255ASM/SFM multicast addresses available for users (IPaddresses of temporary groups). They are globally scopedmulticast addresses.232.0.0.0 to232.255.255.255Available SSM multicast addresses (IP addresses oftemporary groups). They are valid for the entire network.239.0.0.0 to239.255.255.255Administratively scoped multicast addresses. Theseaddresses are constrained to a local group or organization.Use of the administratively scoped addresses allows you todefine the range of multicast domains flexibly to isolateaddresses between different multicast domains, so that thesame multicast address can be used in different multicastdomains without causing collisions.Note that:
