708 Configuring L2 Multicast Features
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. 
PowerConnect 7000 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. 
GMRP is similar to IGMP snooping in its purpose, but IGMP snooping is 
more widely used. GMRP must be running on both the host and the switch to 
function properly.
Default L2 Multicast Values
All L2 multicast features are disabled by default. Details about the L2 
multicast are in Table 25-1.
Table 25-1. L2 Multicast Defaults
Parameter Default Value
Bridge Multicast Filtering Disabled
IGMP Snooping mode Disabled
MLD Snooping mode Disabled
Bridge multicast group None configured
Bridge multicast forwarding mode Forward unregistered
IGMP/MLD snooping Disabled on all interfaces
IGMP/MLD snooping auto-learn Disabled
IGMP/MLD snooping host timeout 260 seconds