АМАТЕК AN-SGM28P24-400 [194/322] Second layer dynamic multicast

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belongs, to guarantee the continuity of network multicast stream。

13.1.2 Second layer dynamic multicast

The multicast MAC address entries in the two layer hardware multicast forwarding table can

be dynamically learned by IGMP SNOOPING. The IP multicast MAC address is dynamically

learned through IGMP SNOOPING。

When the switch off IGMP SNOOPING, the two layer hardware multicast forwarding table

in unregistered forwarding mode, multicast MAC address cannot be dynamically learned that two

layer hardware multicast forwarding table no entries, two layer multicast data stream as all

broadcast processing。

When the network multicast environment, in order to effectively control the multicast traffic

network, the switch can open the IGMP SNOOPING, the two layer hardware multicast forwarding

table in register forwarding mode, the switch can learn to multicast MAC address through the

monitoring network on the IGMP protocol, and the two layer hardware multicast forwarding

entries in the table, the two layer multicast to be able to flow forward。

13.1.3 Join a group

When a host wants to join a multicast group, the host sends a IGMP REPORT packet, which

specifies the multicast group to which the host is to join. When the switch receives a IGMP

QUERY packet, the packet forwarding will switch to the same VLAN all other ports, when the

IGMP QUERY packet is received under the port to join a multicast group after the host return a

IGMP REPORT package. When a IGMP REPORT packet is received, a two layer multicast entry

is established, and the port of the IGMP QUERY packet and the port of the IGMP REPORT

packet are added to the two layer multicast item to become its output port。