Igmp snooping – Dell PowerEdge VRTX User Manual

Page 352

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FILE LOCATION: C:\Users\gina\Desktop\Checkout_new\Dell Plasma\User

Guide\Plasma_UGSwitching_Multicast.fm

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IGMP Snooping

IGMP Snooping can be enabled globally, as described in the Global

Parameters page. It can also be enabled per VLAN to support selective IPv4

Multicast forwarding. In this case, Bridge Multicast filtering must also be

enabled.
By default, a Layer 2 switch forwards Multicast frames to all ports of the

relevant VLAN, essentially treating the frame as if it were a Broadcast. When

IGMP Snooping is enabled per VLAN, the switch forwards Multicast frames

to ports that have registered as Multicast clients in the VLAN.

NOTE:

The switch supports IGMP Snooping only on static VLANs. It does not

support IGMP Snooping on dynamic VLANs.

The IGMP Snooping Querier is used to support a Layer 2 Multicast domain

of snooping switches in the absence of a Multicast router, for example, where

Multicast content is provided by a local server, but the router (if one exists)

on that network does not support Multicast.
There should only be a single IGMP Querier in a Layer 2 Multicast domain.

The switch supports standards-based IGMP Querier election when more than

one IGMP Querier is present in the domain.
The speed of IGMP Querier activity should be aligned with the IGMP-

snooping-enabled switches. Queries should be sent at a rate that is aligned to

the snooping table aging time. If queries are sent at a rate lower than the

aging time, the subscriber cannot receive the Multicast packets.

Filtering: Enabled

VLAN: Forward-All

Port

Static

Status

-------

-----------------

-----------

gi0/3

Forbidden

Filter

gi0/4

Forward

Forward(s)

gi0/5

-

Forward(d)

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