Edge-Core ECS3510-10PD, Management Manual

Page: 619 / 1494

C
HAPTER
17
| Multicast Filtering
Layer 2 IGMP (Snooping and Query for IPv4)
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N
OTE
:
Multicast routers use this information from IGMP snooping and query
reports, along with a multicast routing protocol such as DVMRP or PIM, to
support IP multicasting across the Internet.
P
ARAMETERS
These parameters are displayed:
◆ IGMP Snooping Status – When enabled, the switch will monitor
network traffic to determine which hosts want to receive multicast
traffic. This is referred to as IGMP Snooping. (Default: Enabled)
When IGMP snooping is enabled globally, the per VLAN interface
settings for IGMP snooping take precedence (see "Setting IGMP
Snooping Status per Interface" on page 626 ).
When IGMP snooping is disabled globally, snooping can still be
configured per VLAN interface, but the interface settings will not take
effect until snooping is re-enabled globally.
◆ Proxy Reporting Status – Enables IGMP Snooping with Proxy
Reporting. (Default: Disabled)
When proxy reporting is enabled with this command, the switch
performs “IGMP Snooping with Proxy Reporting” (as defined in DSL
Forum TR-101, April 2006), including last leave, and query
suppression.
Last leave sends out a proxy query when the last member leaves a
multicast group, and query suppression means that specific queries are
not forwarded from an upstream multicast router to hosts downstream
from this device.
When proxy reporting is disabled, all IGMP reports received by the
switch are forwarded natively to the upstream multicast routers.
◆
TCN Flood – Enables flooding of multicast traffic if a spanning tree
topology change notification (TCN) occurs. (Default: Disabled)
When a spanning tree topology change occurs, the multicast
membership information learned by switch may be out of date. For
example, a host linked to one port before the topology change (TC)
may be moved to another port after the change. To ensure that
multicast data is delivered to all receivers, by default, a switch in a
VLAN (with IGMP snooping enabled) that receives a Bridge Protocol
Data Unit (BPDU) with TC bit set (by the root bridge) will enter into
“multicast flooding mode” for a period of time until the topology has
stabilized and the new locations of all multicast receivers are learned.
If a topology change notification (TCN) is received, and all the uplink
ports are subsequently deleted, a time out mechanism is used to delete
all of the currently learned multicast channels.
When a new uplink port starts up, the switch sends unsolicited reports
for all currently learned channels out the new uplink port.
By default, the switch immediately enters into “multicast flooding
mode” when a spanning tree topology change occurs. In this mode,