Users Guide

932 Layer-2 Multicast Features
Enabling MVR and IGMP Snooping on the Same Interface
MVR and IGMP snooping operate independently and can both be enabled on
an interface. When both MVR and IGMP snooping are enabled, MVR listens
to the IGMP join and report messages for static multicast group information,
and IGMP snooping manages dynamic multicast groups.
When Are Layer-3 Multicast Features Required?
In addition to L2 multicast features, the switch suports IPv4 and IPv6
multicast features. You configure the IPv4/IPv6 multicast features if the
switch functions as a multicast router that can route multicast traffic between
VLAN routing interfaces. In this case, you must enable a multicast routing
protocol on the switch, such as PIM-SM. For information about Layer-3
multicast features, see "IPv4 and IPv6 Multicast" on page 1559.
If the switch functions as a multicast router, it is possible to enable IGMP so
that IGMP forwards multicast traffic for directly connected hosts between
VLANs. It is recommended that IGMP snooping and MLD snooping be
enabled in L3 multicast routed networks, as this allows the switch to limit
multicast flooding in multi-access routed VLANs based as controlled by
IGMP snooping.
For information about configuring Dell EMC Networking N3000-ON and
N3100-ON switches as a multicast router that also performs IGMP snooping,
see "Configuring Multicast VLAN Routing With IGMP and PIM-SM" on
page 1638.
What Are GARP and GMRP?
Generic Attribute Registration Protocol (GARP) is a general-purpose protocol
that registers any network connectivity or membership-style information.
GARP defines a set of switches interested in a given network attribute, such
as VLAN ID or multicast address.
Dell EMC Networking N-Series switches can use GARP functionality for two
applications:
• GARP VLAN Registration Protocol (GVRP) to help dynamically manage
VLAN memberships on trunk ports.
NOTE: If MVR is enabled, IP Multicast should be disabled. Multicast routing and
MVR cannot coexist on a switch.