Pathway connectivity solutions Pathport VIA 6730, Руководство пользователя и инструкция

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Pathway Connectivity
VIA 12 Manual
V3 – April 2015
13
VLAN Config/Status: IGMP and Multicast Groups
When using multicast data packets, such as streaming ACN (sACN), bandwidth
efficiency may be improved by using IGMP (Internet group management protocol) to
enable multicast filtering.
Property Explanation
IGMP Snooping
Enable/disable IGMP snooping – allows the switch to
correctly filter multi-cast traffic
IGMP Querier
Enable/disable the IGMP querier – creates the multicast
tables used by snooping
Current Multicast Groups
Shows the table of multi-cast groups in use on the
VLAN. Click on a group to see which ports are
subscribers to that group.
The IGMP Querier establishes a table of active multicast groups by querying connected
devices about which multicast groups each device wishes to join. For example, a
gateway will request the multicast groups associated with the sACN universes that the
gateway is patched to.
Each switch participating in an IGMP-enabled VLAN must have valid IP settings on that
VLAN. The IP settings may be static or dynamically established using the DHCP.
IMPORTANT: Two IGMP queriers should be active on each VLAN using multicast
filtering. If no querier is active, the groupings table will fail after approximately five
minutes and filtering will only work erratically or will fail altogether. IGMP should not be
enabled on more than four VLANs per switch.
The IGMP Snooper allows the switch to more efficiently route multicast traffic by
applying the multicast groupings as a filter. Multicast traffic is only directed to only those
ports, i.e. end devices, that have requested to receive that traffic.
The Current Multicast Groups is a list of the multicast addresses currently maintained in
the Querier’s table. The list provides a troubleshooting check. Click on a listed group to
see what ports are requesting that address. For example, the multicast groups
239.255.237.1, 239.255.237.2 and 239.255.237.255 indicate traffic between Pathport
devices, and all ports connected to Pathports (on that VLAN) should be shown.