clear port mirroring Configuring LACP
Enterasys Matrix DFE-Gold Series Configuration Guide 4-55
Configuring LACP
Usingmultiplelinkssimultaneouslytoincreasebandwidthisadesirableswitchfeature,which
canbeaccomplishedifbothsidesagreeonasetofportsthatarebeingusedasaLinkAggregation
Group(LAG).OnceaLAGisformedfromselectedports,problemswithloopingcanbeavoided
sincethe
SpanningTreecantreatthisLAGasasingleport.
EnabledbydefaultonMatrixdevices,theLinkAggregationControlProtocol(LACP)logically
groupsinterfacestogethertocreateagreaterbandwidthuplink,orlinkaggregation,accordingto
theIEEE802.3adstandard.Thisstandardallowstheswitchtodeterminewhichportsare
inLAGs
andconfigurethemdynamically.SincetheprotocolisbasedontheIEEE802.3adspecification,any
switchfromanyvendorthatsupportsthisstandardcanaggregatelinksautomatically.
802.3adLACPaggregationscanalsoberuntoend‐users(i.e.,aserver)ortoarouter.
LACP Operation
Foreachaggregatableportinthedevice,LACP:
• Maintainsconfigurationinformation(reflectingtheinherentpropertiesoftheindividuallinks
aswellasthoseestablishedbymanagement)tocontrolaggregation.
•ExchangesconfigurationinformationwithotherdevicestoallocatethelinktoaLink
AggregationGroup(LAG).
• Attachestheporttotheaggregatorused
bytheLAG,anddetachestheportfromthe
aggregatorwhenitisnolongerusedbytheLAG.
•Usesinformationfromthepartnerdevice’slinkaggregationcontrolentitytodecidewhether
toaggregateports.
TheoperationofLACPinvolvesthefollowingactivities:
•Checkingtha tcandidate linkscanactuallybeaggregated.
• Controllingthe
additionofalinktoaLAG,andthecreationofthegroupifnecessary.
• Monitoringthestatusofaggregatedlinkstoensurethattheaggregationisstillvalid.
•RemovingalinkfromaLAGifitsmembershipisnolongervalid,andremoving thegroupifit
nolongerhas
anymemberlinks.
InordertoallowLACPtodeterminewhetherasetoflinksconnecttothesamedevice,andto
determinewhetherthoselinksarecompatiblefromthepointofviewofaggregation,itis
necessarytobeabletoestablish
•Agloballyuniqueidentifierforeachdevicethatparticipates
inlinkaggregation.
Caution: Link aggregation configuration should only be performed by personnel who are
knowledgeable about Spanning Tree and Link Aggregation, and fully understand the ramifications
of modifications beyond device defaults. Otherwise, the proper operation of the network could be at
risk.
Note: Earlier (proprietary) implementations of port aggregation referred to groups of aggregated
ports as “trunks”.
Note: A given link is allocated to, at most, one Link Aggregation Group (LAG) at a time. The
allocation mechanism attempts to maximize aggregation, subject to management controls.