What is the difference in the roles of IGMP snooping between Querier, Aggregator, and Access?

Zyxel_Chris Posts: 669  Zyxel Employee
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In the context of Internet Group Management Protocol (IGMP) snooping on a network switch, the terms "Querier," "Aggregator," and "Access" refer to different roles or functions that the switch can perform. Let's explore the distinctions between these roles:


  • Role:
    • The Querier is responsible for generating IGMP Query messages on a VLAN to discover which hosts in that VLAN are members of particular multicast groups.
    • It's usually connected to the streaming server.


  • Role:
    • The Aggregator is not a standard term used in the context of IGMP snooping. It's possible that it could be used informally to describe a switch or device that is aggregating or consolidating information related to multicast group memberships.
    • It's usually located the downstream of Querier role switch.


  • Role:
    • An Access switch is a device that connects directly to end devices such as computers, printers, or IP phones.
    • No streaming server connected, but only connected with the end devices.