IGMP Type 0x11 for Membership Queries

In Internet Group Management Protocol (IGMP), Multicast routers send Membership Queries which uses Type field value of 0x11. There are two sub-types:

  • General Query: This is used to learn which multicast groups have members.
  • Group-Specific Query: This is used to learn if a specific multicast group has members.

General Query

With the general query the multicast group address field is set to 0.0.0.0 and the destination in the IP packet is set to the all multicast host address 224.0.0.1.

Group Specific Query

With the group specific query, the group address field is set to the multicast group address.

https://networklessons.com/multicast/igmp-version-2/ https://datatracker.ietf.org/doc/html/rfc2236#section-2.1