Multicast Global Parameters - Dell PowerConnect 5324 User Manual

Layer 2 switching forwards Multicast packets to all relevant VLAN ports by default, treating the
packet as a Multicast transmission. While this is functional, in the sense that all relevant
ports/nodes receive a copy of the frame, it is potentially wasteful as ports/nodes may receive
irrelevant frames only needed by a subset of the ports of that VLAN. Multicast forwarding filters
enable forwarding of Layer 2 packets to port subsets, defined in the Multicast filter database.
When IGMP snooping is enabled globally, the switching ASIC is programmed to forward all IGMP
packets to the CPU. The CPU analyzes the incoming packets and determines which ports are to
join which Multicast groups, which ports have Multicast routers generating IGMP queries, and
what routing protocols are forwarding packets and Multicast traffic. Ports requesting to join a
specific Multicast group issues an IGMP report specifying that Multicast group. This results in the
creation of the Multicast filtering database.
The Multicast Global Parameters page contains fields for enabling IGMP Snooping on the device.
To open the Multicast Global Parameters page, click Switch Multicast Support Global
Parameters in the tree view.
Figure 7-110. Multicast Global Parameters
Bridge Multicast Filtering — Enables or disables bridge Multicast filtering. Disabled is the default
value.
IGMP Snooping Status — Enables or disables IGMP Snooping on the device. Disabled is the
default value.
Enabling Bridge Multicast Filtering on the Device
1
Open the Multicast Global Parameters page.
2
Select Enable in the Bridge Multicast Filtering field.
3
Click Apply Changes.
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Configuring Device Information