INTERNET GROUP MANAGEMENT
5 PROTOCOL (IGMP) SNOOPING
| This chapter provides the following information about IGMP snooping: | |
| ■ | Overview |
| ■ | CoreBuilder 5000 Support |
| ■ Locating Multicast Routers in the Network | |
| ■ No Multicast Routers on the Network | |
| ■ Enabling IGMP Snooping on CoreBuilder 5000 SwitchModules | |
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Overview | The Internet Group Management Protocol (IGMP) runs between hosts | |
| and their immediate neighboring multicast routers. This protocol is not | |
| a client/server protocol, but rather a routing protocol. | |
Through IGMP, a host to inform its local router that it wants to receive transmissions that are addressed to a specific multicast group. Also, routers periodically query the LAN to determine if known group members are still active.
Based on the group membership information learned from the IGMP, a router can determine which (if any) multicast traffic needs to be forwarded to each of its subnetworks. Multicast routers use this information in conjunction with a multicast routing protocol to support IP multicasting across the Internet. Layer 2 switches flood multicast packets to all ports without the presence of management specified filters.