Ericsson ECN330, User Manual

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Configuring the ECN330-switch
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6.16.2.1 Configuring IGMP Snooping and Query Parameters
The ECN330-switch can be configured to forward multicast traffic intelligently.
Based on the IGMP query and report messages, the ECN330-switch forwards
traffic only to the ports that request multicast traffic. This prevents the ECN330-
switch from broadcasting the traffic to all ports and possibly disrupting network
performance.
Command Usage
• IGMP Snooping – The ECN330-switch can passively snoop on IGMP
Query and Report packets transferred between IP multicast routers/
switches and IP multicast host groups to identify the IP multicast group
members. It simply monitors the IGMP packets passing through it, picks
out the group registration information, and configures the multicast
filters accordingly.
Note: Unknown multicast traffic is flooded to all ports in the VLAN for several
seconds when first received. If a multicast outer port exists on the VLAN, the
traffic will be filtered by subjecting it to IGMP snooping. If no router port exists
on the VLAN, the traffic will simply be dropped.
• IGMP Querier – A router, or multicast-enabled switch, can periodically
ask their hosts if they want to receive multicast traffic. If there is more
than one router/switch on the LAN performing IP multicasting, one of
these devices is elected “querier” and assumes the role of querying the
LAN for group members. It then propagates the service requests on to
any upstream multicast switch/router to ensure that it will continue to
receive the multicast service.
Note: Multicast routers use this information, along with a multicast routing
protocol such as DVMRP or PIM, to support IP multicasting across the Internet.
Command Attributes
• IGMP Status — When enabled, the ECN330-switch will monitor
network traffic to determine which hosts want to receive multicast traffic.
This is also referred to as IGMP Snooping. (Default: Enabled)
• Report Suppression — When enabled, the ECN330-switch forwards
only one IGMP report per query to multicast devices, sending only the
first report from all hosts within a group. Note that report suppression is
not supported when multicast query messages include IGMPv3 reports.
(Default: Enabled)