Igmp Versions 1 And 2 - Enterasys VH-2402-L3 Management Manual

'querier'. This router then keep track of the membership of
multicast groups that have active members on the network.
IGMP is used to determine whether the router should
forward multicast packets it receives to the subnetworks it is
attached to or not. A multicast router that has received a
multicast packet will check to determine if there is at least
one member of a multicast group that has requested to
receive multicast packets from this source. If there is one
member, the packet is forwarded. If there are no members,
the packet is dropped.

IGMP Versions 1 and 2

Users that want to receive multicast packets need to be able
to join and leave multicast groups. This is accomplished
using IGMP.
The IGMP Type codes are shown below:
Type Meaning
Membership Query (if Group Address is 0.0.0.0)
0x11
0x11 Specific Group Membership Query (if Group Address is
Present)
0x16 Membership Report (version 2)
0x17 Leave a Group (version 2)
0x12 Membership Report (version 1)
Multicast routers use IGMP to manage multicast group
memberships:
166 VH-2402-L3 Management Guide
Figure 2-15. IGMP Message Format
Table 2-11. IGMP Type Codes
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