H3C S7500 Series Ethernet Switches Release 3135 DHCP Configuration Examples

Multicast Protocol Configuration Examples
H3C S7500 Series Ethernet Switches Release 3135 Chapter 1 Multicast Protocol Overview
1-1
Chapter 1 Multicast Protocol Overview
1.1 Overview
Different from unicast and broadcast, the multicast technique efficiently addresses the
issue of point-to-multipoint data transmission. By allowing high-efficiency
point-to-multipoint data transmission, multicast greatly saves network bandwidth and
reduces network load.
With the multicast technique, service providers can easily provide new value-added
services, such as live Webcasting, Web TV, distance learning, Telemedicine, Web radio,
real-time videoconferencing, and other bandwidth- and time-critical information
services.
I. IGMP
As a TCP/IP protocol responsible for IP multicast group membership management, the
Internet Group Management Protocol (IGMP) is used by IP hosts to establish and
maintain their multicast group memberships to the immediately neighboring multicast
router.
II. PIM
Protocol Independent Multicast (PIM) provides IP multicast forwarding by leveraging
unicast routing tables generated by static routing or any unicast routing protocol, such
as the Routing Information Protocol (RIP), Open Shortest Path First (OSPF),
Intermediate System to Intermediate System (IS-IS), or the Border Gateway Protocol
(BGP). PIM uses the unicast routing table to perform reverse path forwarding (RPF)
check in multicast forwarding.
Based on the forwarding mechanism, PIM falls into two modes:
z PIM-DM
z PIM-SM
PIM-DM is a type of dense mode multicast protocol. It uses the “push mode” for
multicast forwarding, suitable for small-sized networks with densely distributed
multicast group members. .
PIM-SM is a type of sparse mode multicast protocol. It uses the “pull mode” for
multicast forwarding, suitable for large- and medium-sized networks with sparsely and
widely distributed multicast group members.
III. IGMP Snooping
Internet Group Management Protocol Snooping (IGMP Snooping) is a multicast
monitoring mechanism that runs on Layer 2 devices to manage and control multicast