HP 445946-001 - Manual (Page 120)

IGMP Snooping
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IGMP Filtering
With IGMP Filtering, you can allow or deny a port to send and receive multicast traffic to certain multicast
groups. Unauthorized users are restricted from streaming multicast traffic across the network.
If access to a multicast group is denied, IGMP Membership Reports from the port for that group are
dropped, and the port is not allowed to receive IP multicast traffic from that group. If access to the
multicast group is allowed, Membership Reports from the port are forwarded for normal processing.
To configure IGMP Filtering, you must globally enable IGMP Filtering, define an IGMP Filter, assign the
filter to a port, and enable IGMP Filtering on the port. To define an IGMP Filter, you must configure a
range of IP multicast groups, choose whether the filter will allow or deny multicast traffic for groups within
the range, and enable the filter.
NOTE: Low-numbered filters take precedence over high-number filters. For example, the action
defined for IGMP Filter 1 supersedes the action defined for IGMP Filter 2.
Configuring the range
Each IGMP Filter allows you to set a start and end point that defines the range of IP addresses upon
which the filter takes action. Each IP address in the range must be between 224.0.0.0 and
239.255.255.255.
Configuring the action
Each IGMP Filter can allow or deny IP multicasts to the range of IP addresses configured. If you configure
the filter to deny IP multicasts, then IGMP Membership Reports from multicast groups within the range are
dropped.
You can configure a secondary filter to allow IP multicasts to a small range of addresses within a larger
range that a primary filter is configured to deny. The two filters work together to allow IP multicasts to a
small subset of addresses within the larger range of addresses. The secondary filter must have a lower
number than the primary filter, so that it takes precedence.