Specifications

4.9 MulticastFiltering
Formulticastfiltering,PMISwitchusesIGMPSnoopingtechnology.IGMP
(InternetGroupManagementProtocol)isanInternetProtocolthatprovidesa
wayforinternetdevicetoreportitsmulticastgroupmembershiptoadjacent
routers.Multicastingallowsonecomputerontheinternettosenddatatoa
multitudeofothercomputersthathaveidentifiedthemselvesasbeinginterested
inreceivingtheoriginatingcomputersdata.
Multicastingisusefulforsuchapplicationsasupdatingtheaddressbooksof
mobilecomputerusersinthefield,sendingoutnewsletterstoadistributionlist,
andbroadcastingstreamingmediatoanaudiencethathastunedintotheevent
bysettingupmulticastgroupmembership.
Ineffect,IGMPSnoopingmanagesmulticasttrafficbymakinguseofswitches,
routers,andhoststhatsupportIGMP.EnablingIGMPSnoopingallowstheports
todetectIGMPqueries,reportpackets,andmanagemulticasttrafficthroughthe
switch.IGMPhasthreefundamentaltypesofmessages,asshownbelow:

Message Description
Query A message sent from the  querier (an IGMP router or a switch)
which asks for a response from each host that belongs to the
multicastgroup.
Report A message sent by a host to the querier to indicate  that the
host wants tobe oris a memberof a given group indicated in
thereportmessage.
LeaveGroup A message sent by a host to the querier to indicate that the
hosthasquitasamemberofaspecificmulticastgroup.

YoucanenableIGMPSnoopingandIGMPQueryfunctionshere.Youwillseethe
informationoftheIGMPSnoopingfunctioninthissection,includingdifferent
multicastgroups’VIDandmemberports,andIPmulticastaddressesthatrange
from224.0.0.0to239.255.255.255.
Inthissection,Forcefilteringcandeterminedwhethertheswitchflooding
unknownmulticastornot.
Followingcommandsareincludedinthisgroup:
4.9.1IGMPSnooping
4.9.2IGMPQuery
4.9.3ForceFiltering
4.9.4CLICommandsoftheMulticastFiltering
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4.9.1 IGMPSnooping
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