Chapter 13 WAN

13.3.2 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 85 Multicast Example

Router

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.

13.4 Internet Connection

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

13.4.1 Ethernet Encapsulation

 

119

NBG-419N v2 User’s Guide