Chapter 6 LAN Setup

Assigned Numbers Authority (IANA) has reserved the following three blocks of IP addresses specifically for private networks:

•10.0.0.0 — 10.255.255.255

•172.16.0.0 — 172.31.255.255

•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

224.0.0.1is 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 P-870HN-51D supports both IGMP version 1 (IGMP-v1) and IGMP version 2 (IGMP-v2). At start up, the P-870HN-51D queries all directly connected networks to gather group membership. After that, the P-870HN-51D periodically updates this information. IP multicasting can be enabled/disabled on the P-870HN-51D LAN and/or WAN interfaces in the web configurator (LAN; WAN). Select None to disable IP multicasting on these interfaces.

 

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P-870HN-51D User’s Guide