Dell N2000, N3000, N4000 What Are GARP and GMRP?

810 Configuring L2 Multicast Features
For information about configuring Dell Networking N2000, N3000, and
N4000 series switches as a multicast router that also performs IGMP
snooping, see "Configuring Multicast VLAN Routing With IGMP and PIM-
SM" on page1417.
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 Networking series switches can use GARP functionality for two
applications:
• GARP VLAN Registration Protocol (GVRP) to help dynamically manage
VLAN memberships on trunk ports.
• GARP Multicast Registration Protocol (GMRP) to help control the
flooding of multicast traffic by keeping track of group membership
information.
GVRP and GMRP use the same set of GARP Timers to specify the amount of
time to wait before transmitting various GARP messages.
NOTE: If a multicast source is connected to a VLAN on which both L3 multicast
and IGMP snooping are enabled, the multicast source is forwarde d to the
mrouter ports that have been discovered when the multicast sourc e is first seen.
If a new mrouter is later discovered on a different port, the multica st source data
is not forwarded to the new port. Likewise, if an existing mrouter times out or
stops querying, the multicast source data continues to be forward ed to the
original mrouter port. If a host in the VLAN subsequently joins or leaves the
group, the list of mrouter ports is not updated for the multicast source and the
forwarding of the multicast source is not adjusted. The workaround to this
limitation is to disable IGMP/MLD snooping and avoid the use of multi -access
VLANs in L3 multicast routed topologies.
NOTE: If MVR is enabled, IP Multicast should be disabled. Mul ticast routing and
MVR cannot coexist on a switch.