HP 8000M - Manual (Page 180)

6-104
Configuring the Switch
IP Multicast (IGMP) Features—Multimedia Traffic Control
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N o t e : IP Multicast Filters. IP multicast addresses occur in the range from
224.0.0.0 through 239.255.255.255 (which corresponds to the Ethernet multi-
cast address range of 01005e-000000 through 01005e-7fffff). Any static Traffic/
Security filters (page 6-46) configured with a “Multicast” filter type and a
“Multicast Address” in this range will continue in effect unless IGMP learns of
a multicast group destination in this range. In that case, IGMP takes over the
filtering function for the multicast destination address(es) for as long as the
IGMP group is active. If the IGMP group subsequently deactivates, the static
filter resumes control over traffic to the multicast address formerly controlled
by IGMP.
Reserved Addresses Excluded from IP Multicast (IGMP) Filtering.
Traffic to IP multicast groups in the IP address range of 224.0.0.0 to 224.0.0.255
will always be flooded because addresses in this range are “well known” or
“reserved” addresses. Thus, if IP Multicast is enabled and there is an IP
multicast group within the reserved address range, traffic to that group will
be flooded instead of filtered by the switch.
Number of IP Multicast Addresses Allowed
Multicast filters and IGMP filters (addresses) together can total up to 255 in
the switch. If multiple VLANs are configured, then each filter is counted once
per VLAN in which it is used.
Interaction with Multicast Traffic/Security Filters.
IGMP-controlled filters override multicast filters defined in the Traffic/Secu-
rity Filters screen (page 6-47) and having the same multicast address as
specified by IGMP.