Igmp Operating Features; Igmp Operation With Or Without Ip Addressing - SMC Networks SMC6624M Management Manual

IGMP Operating Features

In the factory default configuration, IGMP is disabled. If multiple VLANs are
not configured, you must configure IGMP on the default VLAN
(DEFAULT_VLAN; VID = 1). If multiple VLANs are configured, you must
configure IGMP on a per-VLAN basis. When you use either the CLI or the web
browser interface to enable IGMP on the switch or a VLAN, the switch
forwards IGMP traffic only to ports belonging to multicast groups. Using the
console enables these additional options:
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Whenever IGMP is enabled, the switch generates an Event Log message
indicating whether querier functionality is enabled.

IGMP Operation With or Without IP Addressing

IGMP operation on the SMC6624M switch does not require an IP address and
subnet mask for each VLAN running IGMP. You can configure IGMP on VLANs
that do not have IP addressing. The benefit of IGMP without IP addressing is
a reduction in the number of IP addresses you have to use and configure. This
can be significant in a network with a large number of VLANs. The limitation
Forward with High Priority. Disabling this parameter (the default)
causes the switch or VLAN to process IP multicast traffic, along with other
traffic, in the order received (normal priority). Enabling this parameter
causes the switch or VLAN to give a higher priority to IP multicast traffic
than to other traffic.
Auto/Blocked/Forward: You can use the console to configure individual
ports to any of the following states:
• Auto (the default): Causes the switch to interpret IGMP packets and
to filter IP multicast traffic based on the IGMP packet information for
ports belonging to a multicast group. This means that IGMP traffic
will be forwarded on a specific port only if an IGMP host or multicast
router is connected to the port.
• Blocked: Causes the switch to drop all IGMP transmissions received
from a specific port and to block all outgoing IP Multicast packets for
that port. This has the effect of preventing IGMP traffic from moving
through specific ports.
• Forward: Causes the switch to forward all IGMP and IP multicast
transmissions through the port.
Querier: In the default state (enabled), eliminates the need for a multicast
router. In most cases, SMC recommends that you leave this parameter in
the default "enabled" state even if you have a multicast router performing
the querier function in your multicast group.
Configuring Advanced Features
Multimedia Traffic Control with IP Multicast (IGMP)
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