83
4.8 Multicast Filtering
For multicast filtering, JetNet 5728G uses IGMP Snooping technology. IGMP (Internet
Group Management Protocol) is an Internet Protocol that provides a way for internet
device to report its multicast group membership to adjacent routers. Multicasting allows
one computer on the internet to send data to a multitude of other computers that have
identified themselves as being interested in receiving the originating computers data.
Multicasting is useful for such applications as updating the address books of mobile
computer users in the field, sending out newsletters to a distribution list, and broadcasting
streaming media to an audience that has tuned into the event by setting up multicast group
membership.
In effect, IGMP Snooping manages multicast traffic by making use of switches, routers,
and hosts that support IGMP. Enabling IGMP Snooping allows the ports to detect IGMP
queries, report packets, and manage multicast traffic through the switch. IGMP has three
fundamental types of messages, as shown below:
Message
Description
Query
A message sent from the querier (an IGMP router or a switch) which
asks for a response from each host that belongs to the multicast group.
Report
A message sent by a host to the querier to indicate that the host wants
to be or is a member of a given group indicated in the report message.
Leave Group
A message sent by a host to the querier to indicate that the host has
quit as a member of a specific multicast group.
You can enable IGMP Snooping and IGMP Query functions here. You will see the
information of the IGMP Snooping function in this section, including different multicast
groups’ VID and member ports, and IP multicast addresses that range from 224.0.0.0 to
239.255.255.255.
In this section, Force filtering can determined whether the switch flooding unknown
multicast or not.
Following commands are included in this group:
4.8.1 IGMP Snooping
4.8.2 IGMP Query
4.8.3 Unknown Multicast
4.8.4 CLI Commands of the Multicast Filtering
4.8.1
IGMP Snooping
This page is to enable IGMP Snooping feature, assign IGMP Snooping for specific VLAN,
and view IGMP Snooping table from dynamic learnt or static manual key-in. JetNet5728G
support IGMP snooping V1/V2/V3 automatically and IGMP query V1/V2.
IGMP Snooping, you can select Enable or Disable here. After enabling IGMP Snooping,
you can then enable IGMP Snooping for specific VLAN. You can enable IGMP Snooping
for some VLANs so that some of the VLANs will support IGMP Snooping and others won’t.
To assign IGMP Snooping to VLAN, please select the checkbox of VLAN ID or select
Select All checkbox for all VLANs. Then press Enable. In the same way, you can also
Disable IGMP Snooping for certain VLANs.
