97ConfigureThe IP Trap Entry screen appears.Enter an IP Trap Entry IP address. This is the destination for SNMP trap messages, the IPaddress of the host acting as an SNMP console.Click theSubmit button. Click the Alert icon, and in the resulting page, click theSaveand Restart link.Link: 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, anddata services to the set of computers which have joined a distributed conference. Otheruses include: updating the address books of mobile computer users in the field or sendingout company newsletters to a distribution list.Since a router should not be used as a passive forwarding device, Netopia Routers use aprotocol for forwarding multicasting: Internet Group Management Protocol (IGMP). NetopiaRouters can use either IGMP Version 1 or Version 2.IGMP “Snooping” is a feature of Ethernet layer 2 switches that “listens in” on the IGMPconversation between computers and multicast routers. Through this process, it builds adatabase of where the multicast routers reside by noting IGMP general queries used in thequerier selection process and by listening to other router protocols.From the host point of view, the snooping function listens at a port level for an IGMPreport. The switch then processes the IGMP report and starts forwarding the relevant mul-ticast stream onto the host's port. When the switch receives an IGMP leave message, itprocesses the leave message, and if appropriate stops the multicast stream to that partic-ular port. Basically, customer IGMP messages although processed by the switch are alsosent to the multicast routers.
