Chapter 10 WAN
NBG6716 User’s Guide
76
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 49
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 NBG6716 supports both IGMP version 1
(
IGMP-v1
) and IGMP version 2 (
IGMP-v2
).
At start up, the NBG6716 queries all directly connected networks to gather group membership.
After that, the NBG6716 periodically updates this information. IP multicasting can be enabled/
disabled on the NBG6716 WAN interface in the Web Configurator (
WAN
). Select
None
to disable IP
multicasting on these interfaces.
10.4
Internet Connection
Use this screen to change your NBG6716’s Internet access settings. Click
Network
>
WAN
from
the
Configuration
menu. The screen differs according to the encapsulation you choose.
10.4.1
IPoE Encapsulation
This screen displays when you select
IPoE
encapsulation.