Multicast Addresses - H3C S3610 Series Operation Manual

Operation Manual – Multicast Protocol
H3C S3610&S5510 Series Ethernet Switches
Addressing mechanism: Information is sent from a multicast source to a group of
receivers through a multicast address.
Host registration: Receiver hosts are allowed to join and leave multicast groups
dynamically. This mechanism is the basis for group membership management.
Multicast routing: A multicast distribution tree (namely a forwarding path tree for
multicast data on the network) is constructed for delivering multicast data from a
multicast source to receivers.
Multicast applications: A software system that supports multicast applications,
such as video conferencing, must be installed on multicast sources and receiver
hosts, and the TCP/IP stack must support reception and transmission of multicast
data.

1.3.1 Multicast Addresses

To 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-layer
multicast MAC addresses.
I. IPv4 multicast addresses
Internet 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 description
Address block
224.0.0.0
224.0.0.255
224.0.1.0
231.255.255.255
233.0.0.0
238.255.255.255
232.0.0.0
232.255.255.255
239.0.0.0
239.255.255.255
Note that:
Reserved multicast addresses (addresses for permanent
to multicast groups). The IP address 224.0.0.0 is reserved, and
other IP addresses can be used by routing protocols and for
topology searching and protocol maintenance.
to
ASM/SFM multicast addresses available for users (IP
addresses of temporary groups). They are globally scoped
to
multicast addresses.
to Available SSM multicast addresses (IP addresses of
temporary groups). They are valid for the entire network.
Administratively
addresses are constrained to a local group or organization.
Use of the administratively scoped addresses allows you to
to
define the range of multicast domains flexibly to isolate
addresses between different multicast domains, so that the
same multicast address can be used in different multicast
domains without causing collisions.
1-6
Chapter 1 Multicast Overview
Description
scoped multicast addresses. These