ZyXEL Communications P-870HN-51B - V1.0 Manual page 99

Assigned Numbers Authority (IANA) has reserved the following three blocks of IP
addresses specifically for private networks:
• 10.0.0.0
• 172.16.0.0
• 192.168.0.0 — 192.168.255.255
You can obtain your IP address from the IANA, from an ISP or it can be assigned
from a private network. If you belong to a small organization and your Internet
access is through an ISP, the ISP can provide you with the Internet addresses for
your local networks. On the other hand, if you are part of a much larger
organization, you should consult your network administrator for the appropriate IP
addresses.
Note: Regardless of your particular situation, do not create an arbitrary IP address;
always follow the guidelines above. For more information on address
assignment, please refer to RFC 1597, "Address Allocation for Private
Internets" and RFC 1466, "Guidelines for Management of IP Address Space".
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.
P-870HN-51b User's Guide
— 10.255.255.255
— 172.31.255.255
Chapter 6 LAN Setup
99