D-Link xStack DGS-3610 Series Configuration Manual page 460

Chapter 35 IP Multicast Routing Configuration
35.1.2.3 IGMPV3
In the applications of the IGMPV1 and V2, there are the following defects:
Lack of effective measures to control multicast sources

Difficult to establish the multicast path due to the unknown location of the multicast

source
Difficult to find a unique multicast address, possibly multicast groups are using the

same multicast address.
On the basis of the IGMPV1/V2, the IGMPV3 provides an additional source filtering multicast
function. In the IGMP V1/V2, the host determines to join a group and receive the multicast
traffic to the group address from any source only based on the group address. On the other
hand, the host running the IGMP V3 notifies this host the desired multicast group to join, and
also the addresses of the multicast sources to receive. The host can indicate that it wants to
receive multicast traffic from which sources through a list or an exclusion list. At the same
time, another benefit of the IGMP v3 is that it saves bandwidth to avoid unnecessary, invalid
multicast data traffics from occupying network bandwidth. It is particularly useful in the case
where multiple multicast sources share one multicast address. The IGMPv1 and IGMPv2
can also implement ―source address filters‖ in some sense, which, is performed on the
reception end of the multicast traffic. As shown in the following diagram, there are two
multicast sources (S1 and S2), which send the data traffic of the same multicast address (G).
The multicast flow of S1 and S2 will be sent to all hosts that are receiving from G, If host A
only wants to receive that of S1, filtering on the terminal by using the related client software
has to be used to keep out the interference of S2 dataflow.
Figure 35-2
35-4
IGMP V1/V2 forwarding diagram
DGS-3610 Series Configuration Guide