User`s manual

IKS-6726 Featured Functions
3-48
When the report packet arrives at a port on a switch with IGMP Snooping enabled, the switch knows that the
port should forward traffic for the multicast group, and then proceeds to forward the packet to the router.
When the router receives the report packet, it registers that the LAN or VLAN requires traffic for the multicast
groups.
When the router forwards traffic for the multicast group to the LAN or VLAN, the switches only forward the
traffic to ports that received a report packet.
GMRP (GARP Multicast Registration Protocol)
The IKS-6726 supports IEEE 802.1D-1998 GMRP (GARP Multicast Registration Protocol), which differs from
IGMP (Internet Group Management Protocol). GMRP is a MAC-based multicast management protocol, whereas
IGMP is IP-based. GMRP provides a mechanism that allows bridges and end stations to register or de-register
Group membership information dynamically. GMRP functions similarly to GVRP, except that GMRP registers
multicast addresses on ports. When a port receives a GMRP-join message, it will register the multicast
address to its database if the multicast address is not registered, and all the multicast packets with that
multicast address are able to be forwarded from this port. When a port receives a GMRP-leave message, it will
de-register the multicast address from its database, and all the multicast packets with this multicast address
are not able to be forwarded from this port.
Static Multicast MAC
Some devices may only support multicast packets, but not support either IGMP Snooping or GMRP. The
IKS-6726 supports adding multicast groups manually to enable multicast filtering.
Enabling Multicast Filtering
Use the serial console or Web interface to enable or disable IGMP Snooping and IGMP querying. If IGMP
Snooping is not enabled, then IP multicast traffic is always forwarded, flooding the network.
Configuring IGMP Snooping
IGMP Snooping provides the ability to prune multicast traffic so that it travels only to those end destinations
that require that traffic, thereby reducing the amount of traffic on the Ethernet LAN.
IGMP Snooping Settings
IGMP Snooping Enable
Setting Description Factory Default
Enable/Disable Click the checkbox to enable the IGMP Snooping function
globally.
Disabled