Multicast - ZyXEL Communications NBG6503 User Manual

11.3.2 Multicast

Traditionally, IP packets are transmitted in one of either two ways - Unicast (1 sender - 1 recipient)
or Broadcast (1 sender - everybody on the network). Multicast delivers IP packets to a group of
hosts on the network - not everybody and not just 1.
Figure 71 Multicast Example
In the multicast example above, systems A and D comprise one multicast group. In multicasting,
the server only needs to send one data stream and this is delivered to systems A and D.
IGMP (Internet Group Multicast Protocol) is a network-layer protocol used to establish membership
in a multicast group - it is not used to carry user data. The Router supports both IGMP version 1
(IGMP-v1) and IGMP version 2 (IGMP-v2).
At start up, the Router queries all directly connected networks to gather group membership. After
that, the Router periodically updates this information. IP multicasting can be enabled/disabled on
the Router LAN and/or WAN interfaces in the Web Configurator (LAN; WAN). Select None to
disable IP multicasting on these interfaces.
NBG6503 User's Guide
Router
Chapter 11 WAN
101