HP procurve 8100fl series Management And Configuration Manual page 167

Multimedia Traffic Control with IP Multicast (IGMP)
How IGMP Operates
N o t e s :
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
multicast address range of 01005e-000000 through 01005e-7fffff). Where a
switch has a static Traffic/Security filter configured with a "Multicast" filter
type and a "Multicast Address" in this range, the switch will use the static filter
unless IGMP learns of a multicast group destination in this range. In this case,
IGMP dynamically 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 switch returns filtering control to the
static filter.
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. The 8100fl switch supports
up to 1000 IGMP filters (addresses). If multiple VLANs are configured, then
each filter is counted once per VLAN in which it is used.
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