ZyXEL Communications Corporation NBG6616 Manuel D’Utilisation

Chapter 10 WAN

NBG6616 User’s Guide

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. 

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 NBG6616 supports both IGMP version 1 
(IGMP-v1) and IGMP version 2 (IGMP-v2). 

At start up, the NBG6616 queries all directly connected networks to gather group membership. 
After that, the NBG6616 periodically updates this information. IP multicasting can be enabled/
disabled on the NBG6616 WAN interface in the Web Configurator (WAN). Select None to disable IP 
multicasting on these interfaces.

Use this screen to change your NBG6616’s Internet access settings. Click Network > WAN from 
the Configuration menu. The screen differs according to the encapsulation you choose.

This screen displays when you select IPoE encapsulation.