To Next Page

To Previous Page

Link Aggregation Control Protocol (LACP)

4-34 Port Configuration

standard.ThisstandardallowstheswitchtodeterminewhichportsareinLAGsandconfigure

themdynamically.SincetheprotocolisbasedontheIEEE802.3adspecification,anyswitchfrom

anyvendorthatsupportsthisstandardcanaggregatelinksautomatically.

802.3adLACPaggregationscanalsoberuntoend‐users(that

is,aserver)ortoarouter.

LACP Operation

Foreachaggregatableportinthedevice,LACP:

• Maintainsconfigurationinformation(reflectingtheinherentpropertiesoftheindividuallinks

aswellasthoseestablishedbymanagement)tocontrolaggregation.

•Exchangesconfigurationinformati onwithotherdevicestoallocatethelinktoaLink

AggregationGroup(LAG).

• Attachestheporttotheaggregatorused

bytheLAG,anddetachestheportfromthe

aggregatorwhenitisnolongerusedbytheLAG.

•Usesinformationfromthepartnerdevice’slinkaggregationcontrolentitytodecidewhether

toaggregateports.

TheoperationofLACPinvolvesthefollowingactivities:

•Checkingtha tcandidatelinkscanactuallybeaggregated.

• Controllingthe

additionofalinktoaLAG,andthecreationofthegroupifnecessary.

• Monitoringthestatusofaggregatedlinkstoensurethattheaggregationisstillvalid.

•RemovingalinkfromaLAGifitsmembershipisnolongervalid,andremovingthegroupifit

nolongerhas

anymemberlinks.

InordertoallowLACPtodeterminewhetherasetoflinksconnecttothesamedevice,andto

determinewhetherthoselinksarecompatiblefromthepointofviewofaggregation,itis

necessarytobeabletoestablish

•Agloballyuniqueidentifierforeachdevicethatparticipates

inlinkaggregation.

•Ameansofidentifyingthesetofcapabilitiesassociatedwitheachportandwitheach

aggregator,asunderstoodbyagivendevice.

•AmeansofidentifyingaLAGanditsassociatedaggrega tor.

LACP Terminology

Table 4‐15defineskeyterminologyusedinLACPconfiguration.

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.

Note: The path cost of a LAG port will be displayed as zero when it is not an active link.

Enterasys D2 D2G124-12P User Manual

Questions and Answers: