How To Configure Igmp - HP J3100B Installation And Configuration Manual

Advanced Concepts
IP Multicast (IGMP)
N o t e
IP multicast addresses occur in the range from 224.0.0.0 through
239.255.255.255. When IGMP is enabled, any Traffic/Security filters (page 7-8)
configured with a "Multicast" filter type and a "Multicast Address" within the
above range are disabled and an event log message indicating this action is
logged . That is, IGMP will control the IP multicast traffic flow and the Traffic/
Security filter will control any multicast traffic that is not IP multicast traffic.

How To Configure IGMP

In the factory default configuration, IGMP is disabled. If multiple VLANs are
configured, you can configure IGMP on a per-VLAN basis. The configuration
options include:
Per-Port handling of IP multicast traffic. In the factory default state
(IGMP disabled), the switch forwards all IGMP traffic. When IGMP is enabled,
you can configure the switch to do any of the following on a per-port basis:
7-26
Enabling or disabling IGMP. Disabling IGMP (the default) causes all
ports on the switch or VLAN to simply forward IP multicast traffic.
Enabling IGMP allows the ports to detect IGMP queries and report packets
and manage IP multicast traffic through the switch. If no other querier is
detected, the switch will then also function as the querier. (If you need to
disable the querier feature, you can do so through the IGMP configuration
MIB. Refer to "Changing the Querier Configuration Setting" on page 7-29.)
High-priority forwarding. Disabling this parameter (the default) causes
the switch or VLAN to process IP multicast traffic, along with other traffic,
in the order received. If priority forwarding is supported by the network
technology you are using (such as Hewlett-Packard's implementation of
100Base-TX), enabling this parameter causes the switch or VLAN to give
a higher priority to IP multicast traffic than to other traffic.
• Automatic (the default): Causes the switch to interpret IGMP packets
and to filter IP multicast traffic based on the IGMP packet information
for that port.
• Blocking: Causes the switch to drop all IGMP transmissions received
and block all outgoing IP Multicast packets for that port.
• Forwarding: Causes the switch to forward all IGMP and IP multicast
transmissions through the port.