ZyXEL 793H Guida Utente
Chapter 6 LAN Setup
P-793H User’s Guide
97
6.2.3 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 network-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 ZyXEL Device supports both IGMP version 1 (IGMP-v1) and IGMP version 2 (IGMP-
v2). At start up, the ZyXEL Device queries all directly connected networks to gather group
membership. After that, the ZyXEL Device periodically updates this information. IP
multicasting can be enabled/disabled on the ZyXEL Device LAN and/or WAN interfaces in
the web configurator (LAN; WAN). Select None to disable IP multicasting on these
interfaces.
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 network-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 ZyXEL Device supports both IGMP version 1 (IGMP-v1) and IGMP version 2 (IGMP-
v2). At start up, the ZyXEL Device queries all directly connected networks to gather group
membership. After that, the ZyXEL Device periodically updates this information. IP
multicasting can be enabled/disabled on the ZyXEL Device LAN and/or WAN interfaces in
the web configurator (LAN; WAN). Select None to disable IP multicasting on these
interfaces.
6.3 Configuring LAN IP
Use this screen to set the LAN IP address of your ZyXEL Device. Click LAN > IP. See
for background information.
Figure 38 LAN > IP
The following table describes the fields in this screen.
Table 24 LAN > IP
LABEL
DESCRIPTION
IP Address
Enter the IP address of your ZyXEL Device in dotted decimal notation, for
example, 192.168.1.1 (factory default).
IP Subnet Mask
Type the subnet mask for your network. See
for more
information.
Apply
Click Apply to save your changes back to the ZyXEL Device.
Cancel
Click Cancel to begin configuring this screen afresh.
Advanced Setup
Click this button to display the Advanced LAN Setup screen and edit more
details of your LAN setup.