Ip Multicast; Ip Alias; Figure 3-1 Physical Network; Figure 3-2 Partitioned Logical Networks - ZyXEL Communications Prestige 310 User Manual

Prestige 310 Broadband Sharing Gateway

3.1.6 IP 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.
IGMP (Internet Group Multicast Protocol) is a session-layer protocol used to establish membership in a
Multicast group - it is not used to carry user data. IGMP version 2 (RFC 2236) is an improvement over
version 1 (RFC 1112) but IGMP version 1 is still in wide use. If you would like to read more detailed
information about interoperability between IGMP version 2 and version 1, please see sections 4 and 5 of
RFC 2236. The class D IP address is used to identify host groups and can be in the range 224.0.0.0 to
239.255.255.255. The address 224.0.0.0 is not assigned to any group and is used by IP multicast computers.
The address 224.0.0.1 is used for query messages and is assigned to the permanent group of all IP hosts
(including gateways). All hosts must join the 224.0.0.1 group in order to participate in IGMP. The address
224.0.0.2 is assigned to the multicast routers group.
The Prestige supports both IGMP version 1 (IGMP-v1) and IGMP version 2 (IGMP-v2). At start up, the
Prestige queries all directly connected networks to gather group membership. After that, the Prestige
periodically updates this information. IP Multicasting can be enabled/disabled on the Prestige LAN and/or
WAN interfaces using menus 3.2 (LAN) and 11.3 (WAN). Select None to disable IP Multicasting on these
interfaces.

3.1.7 IP Alias

IP Alias allows you to partition a physical network into different logical networks over the same Ethernet
interface. The Prestige supports three logical LAN interfaces via its single physical Ethernet interface with
the Prestige itself as the gateway for each LAN network.

Figure 3-1 Physical Network

Figure 3-2 Partitioned Logical Networks

3-4 Internet Access