Edge-Core ECS4110-28T Management Manual page 569

network segments where no node has expressed interest in receiving a
specific multicast service. For switches that do not support multicast
routing, or where multicast routing is already enabled on other switches in
the local network segment, IGMP Snooping is the only service required to
support multicast filtering.
When using IGMPv3 snooping, service requests from IGMP Version 1, 2 or
3 hosts are all forwarded to the upstream router as IGMPv3 reports. The
primary enhancement provided by IGMPv3 snooping is in keeping track of
information about the specific multicast sources which downstream
IGMPv3 hosts have requested or refused
information about both multicast groups and channels, where a group
indicates a multicast flow for which the hosts have not requested a specific
source (the only option for IGMPv1 and v2 hosts unless statically
configured on the switch), and a channel indicates a flow for which the
hosts have requested service from a specific source. For IGMPv1/v2 hosts,
the source address of a channel is always null (indicating that any source is
acceptable), but for IGMPv3 hosts, it may include a specific address when
requested.
Only IGMPv3 hosts can request service from a specific multicast source.
When downstream hosts request service from a specific source for a
multicast service, these sources are all placed in the Include list, and traffic
is forwarded to the hosts from each of these sources. IGMPv3 hosts may
also request that service be forwarded from any source except for those
specified. In this case, traffic is filtered from sources in the Exclude list,
and forwarded from all other available sources.
When the switch is configured to use IGMPv3 snooping, the
N :
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snooping version may be downgraded to version 2 or version 1, depending
on the version of the IGMP query packets detected on each VLAN.
IGMP snooping will not function unless a multicast router port is
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enabled on the switch. This can accomplished in one of two ways. A static
router port can be manually configured (see
for a Multicast Router" on page
never timed out, and will continue to function until explicitly removed. The
other method relies on the switch to dynamically create multicast routing
ports whenever multicast routing protocol packets or IGMP query packets
are detected on a port.
A maximum of up to 1023 multicast entries can be maintained for
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IGMP snooping. Once the table is full, no new entries are learned. Any
subsequent multicast traffic not found in the table is dropped if
unregistered-flooding is disabled (default behavior) and no router port is
configured in the attached VLAN, or flooded throughout the VLAN if
unregistered-flooding is enabled (see
Query Parameters" on page
Static IGMP Router Interface – If IGMP snooping cannot locate the IGMP
querier, you can manually designate a known IGMP querier (i.e., a
multicast router/switch) connected over the network to an interface on
17. Source IP lists is not supported in IGMPv3 reports by the switch due to an ASIC limitation.
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C
HAPTER
Layer 2 IGMP (Snooping and Query for IPv4)
. The switch maintains
17
"Specifying Static Interfaces
574). Using this method, the router port is
"Configuring IGMP Snooping and
570).
| Multicast Filtering
15