UTStarcom iSpirit 3026 Manual page 86

receives an IGMP QUERY packet, it will send it to all other ports in the same VLAN; when a host
hoping to join the group gets the QUERY packet, it will respond with an IGMP REPORT packet;
when the REPORT packet arrives at the switch, a Layer 2 multicast entry will be created, with its
output ports list being the union of the ingress port of the QUERY packet and the ingress port of
the REPORT packet.
An example is shown in Figure7-1.
Figure7-1.example
As shown in Figure7-1, all devices are in the same subnet, suppose it's VLAN 2. IGMPv2 is
running on the router, which sends out IGMP QUERY packets periodically. Host 1 wants to join
the group 224.1.1.1. When the switch receives an IGMP QUERY packet from port 3/1, it will
record the ingress port and transmits the packet to port 1/1 and port 1/2; Host 1 will respond with
an IGMP REPORT packet after receiving the QUERY packet, while it's not for Host 2 since it
doesn't want to join the group; After the switch receives the REPORT packet from port 1/1, it will
send it out from the ingress port 3/1 for the previous QUERY packet and create a Layer 2
multicast entry (support it's not existent already) with following fields (shown in Table7-1):
Tabel 7-1:
Layer 2 multicast ddress Vlan ID Output port list
01:00:5e:01:01:01 2 1/1 , 3/1