ZyXEL NBG420N User Guide - Page 128

IP Address and Subnet Mask, Multicast, Any IP

Page 128 highlights

Chapter 9 LAN 9.2.2 IP Address and Subnet Mask Refer to the IP address and subnet mask section in the Connection Wizard chapter for this information. 9.2.3 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 Management 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 NBG420N supports both IGMP version 1 (IGMP-v1) and IGMP version 2 (IGMP-v2). At start up, the NBG420N queries all directly connected networks to gather group membership. After that, the NBG420N periodically updates this information. IP multicasting can be enabled/disabled on the NBG420N LAN and/or WAN interfaces in the web configurator (LAN; WAN). Select None to disable IP multicasting on these interfaces. 9.2.4 Any IP Traditionally, you must set the IP addresses and the subnet masks of a computer and the NBG420N to be in the same subnet to allow the computer to access the Internet (through the NBG420N). In cases where your computer is required to use a static IP address in another network, you may need to manually configure the network settings of the computer every time you want to access the Internet via the NBG420N. With the Any IP feature and NAT enabled, the NBG420N allows a computer to access the Internet without changing the network settings (such as IP address and subnet mask) of the computer, when the IP addresses of the computer and the NBG420N are not in the same subnet. Whether a computer is set to use a dynamic or static (fixed) IP address, you can simply connect the computer to the NBG420N and access the Internet. The following figure depicts a scenario where a computer is set to use a static private IP address in the corporate environment. In a residential house where a NBG420N is installed, you can still use the computer to access the Internet without changing the network settings, even when the IP addresses of the computer and the NBG420N are not in the same subnet. 128 NBG420N User's Guide

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Chapter 9 LAN
NBG420N User’s Guide
128
9.2.2
IP Address and Subnet Mask
Refer to the IP address and subnet mask section in the
Connection
Wizard
chapter for this
information.
9.2.3
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 Management 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 NBG420N supports both IGMP version 1 (
IGMP-v1
) and IGMP version 2 (
IGMP-v2
).
At start up, the NBG420N queries all directly connected networks to gather group
membership. After that, the NBG420N periodically updates this information. IP multicasting
can be enabled/disabled on the NBG420N LAN and/or WAN interfaces in the web
configurator (
LAN
;
WAN
). Select
None
to disable IP multicasting on these interfaces.
9.2.4
Any IP
Traditionally, you must set the IP addresses and the subnet masks of a computer and the
NBG420N to be in the same subnet to allow the computer to access the Internet (through the
NBG420N). In cases where your computer is required to use a static IP address in another
network, you may need to manually configure the network settings of the computer every time
you want to access the Internet via the NBG420N.
With the Any IP feature and NAT enabled, the NBG420N allows a computer to access the
Internet without changing the network settings (such as IP address and subnet mask) of the
computer, when the IP addresses of the computer and the NBG420N are not in the same
subnet. Whether a computer is set to use a dynamic or static (fixed) IP address, you can simply
connect the computer to the NBG420N and access the Internet.
The following figure depicts a scenario where a computer is set to use a static private IP
address in the corporate environment. In a residential house where a NBG420N is installed,
you can still use the computer to access the Internet without changing the network settings,
even when the IP addresses of the computer and the NBG420N are not in the same subnet.