Multicast Filtering
241
Instruction Manual - NXA-ENET8-POE+
Perform these steps to configure IGMP snooping on a VLAN:
1.
Click
Multicast
>
IGMP Snooping
>
Interface
.
2.
Select
Configure VLAN
from the Action list.
3.
Select the VLAN to configure and update the required parameters.
4.
Click
Apply
.
Query Interval
The interval between sending IGMP general queries. (Range: 2-31744 seconds; Default: 125
seconds)
An IGMP general query message is sent by the switch at the interval specified by this attribute.
When this message is received by downstream hosts, all receivers build an IGMP report for the
multicast groups they have joined.
This attribute applies when the switch is serving as the querier (page 234), or as a proxy host
when IGMP snooping proxy reporting is enabled (page 234).
Query Response Interval
The maximum time the system waits for a response to general queries. (Range: 10-31740 tenths
of a second in multiples of 10; Default: 10 seconds)
This attribute applies when the switch is serving as the querier (page 234), or as a proxy host
when IGMP snooping proxy reporting is enabled (page 234).
Last Member Query Interval
The interval to wait for a response to a group- specific or group-and-source-specific query
message. (Range: 1-31744 tenths of a second in multiples of 10; Default: 1 second)
When a multicast host leaves a group, it sends an IGMP leave message. When the leave message is
received by the switch, it checks to see if this host is the last to leave the group by sending out an
IGMP group-specific or group-and- source-specific query message, and starts a timer. If no
reports are received before the timer expires, the group record is deleted, and a report is sent to
the upstream multicast router.
A reduced value will result in reduced time to detect the loss of the last member of a group or
source, but may generate more burst traffic.
This attribute will take effect only if IGMP snooping proxy reporting is enabled (page 234) or IGMP
querier is enabled (page 234).
Last Member Query Count
The number of IGMP proxy group-specific or group-and-source-specific query messages that are
sent out before the system assumes there are no more local members. (Range: 1-255; Default: 2)
This attribute will take effect only if IGMP snooping proxy reporting or IGMP querier is enabled.
Proxy Query Address
A static source address for locally generated query and report messages used by IGMP Proxy
Reporting. (Range: Any valid IP unicast address; Default: 0.0.0.0)
IGMP Snooping uses a null IP address of 0.0.0.0 for the source of IGMP query messages which are
proxied to downstream hosts to indicate that it is not the elected querier, but is only proxying these
messages as defined in RFC 4541. The switch also uses a null address in IGMP reports sent to
upstream ports.
Many hosts do not implement RFC 4541, and therefore do not understand query messages with
the source address of 0.0.0.0. These hosts will therefore not reply to the queries, causing the
multicast router to stop sending traffic to them.
To resolve this problem, the source address in proxied IGMP query messages can be replaced with
any valid unicast address (other than the router's own address).
FIG. 282
Configuring IGMP Snooping on a VLAN
Multicast - IGMP Snooping (Interface) Options