Motorola 6161252-00-01, Enterprise Series Routers manual Igmp Internet Group Management Protocol

3-52 Administrator’s Handbook

If you chose CONTINUE, the device will reboot and restart in the selected mode. Routing features will be disabled or changed and the Telnet menus corresponding configuration items, such as Easy Setup, will be removed.

Example of Bridge-only mode menus

Netopia Router

WAN Configuration...

System Configuration...

Utilities & Diagnostics...

Statistics & Logs...

Quick View...

If you decide to return to the previous mode, you can repeat the process. Remember that you will have to reconfigure all your previous settings.

IGMP (Internet Group Management Protocol)

Multicasting is a method for transmitting large amounts of information to many, but not all, computers over an Internet. One common use is to distribute real time voice, video, and data services to the set of computers which have joined a distributed conference. Other uses include: updating the address books of mobile computer users in the field or sending out company newsletters to a distribution list.

Since a router should not be used as a passive forwarding device, Motorola Netopia® Routers use a protocol for forwarding multicasting: Internet Group Management Protocol (IGMP).

Motorola Netopia® Gateways support IGMP Version 1, Version 2 or Version 3. See “Multicast Forwarding” on page 7-32 for more information.

Unicasting multicast-streams for a wireless link aims at improving the receipt of multicast data by a wireless client. (The router replaces the multicast MAC-address with the physical MAC-address of the wireless client. If there is more than one wireless client interested in the same multicast group, the router will revert to multicasting the stream immediately. When one or more wireless clients leave a group, and the router determines that only a single wireless client is interested in the stream, it will once again unicast the stream.)

This feature is only available if IGMP Snooping is enabled.

IGMP “Snooping” is a feature of Ethernet layer 2 switches that “listens in” on the IGMP conversation between computers and multicast routers. Through this process, it builds a database of where the multicast routers reside by noting IGMP general queries used in the querier selection process and by listening to other router protocols.