Specifications

January 29, 2009 Page 1 of 4
Configuring Link Flap Detection
Thisdocumentprovidesinformationaboutconfiguringthelinkflapdetectionfeatureon
EnterasysMatrix
®
N‐Series,EnterasysSecureStack
™
,D‐Series,G‐Series,andI‐Seriesdevices.
What is Link Flap Detection?
Thelinkflapdetectionfeaturemonitorslinkflapping(thatis,whenalinkgoesupanddown
rapidly)onaphysicalport.LinkflappingindicatesaLayer1(physicallayer)problem,suchasa
faultycableorGBIC.Iflinkflappingoccurs,yourEnterasysdevicecanreactbydisablingthe
affected
portandgeneratingasyslogentryandanSNMPtraptonotifyyouoftheevent.
Why Would I Use Link Flap Detection in My Network?
Ifleftunresolved,linkflappingcanbedetrimentaltonetworkstabilitybytriggeringSpanning
Treeandroutingtablerecalcu lat ions.ByenablingthelinkflapdetectionfeatureonyourEnterasys
device,youcanmonitorandactuponlinkflappingtoavoidtheserecalculations.
How Do I Implement Link Flap Detection?
YoucanenablelinkflapdetectiongloballyonyourEnterasysdeviceoronspecificports,suchas
uplinkports.Thelinkflapdetectionfeatureallowsyoutospecifytheactionthatoccurswhena
certainnumberoflinkflappinginstancesoccurwithinacertainperiodoftime.Bydefault,ifa
port
onwhichlinkflapisenabledexperiencesfivelinkflappinginstanceswithina10‐secondperiod,
thatportwillbedisabledfor 300secondsandbothasyslogentryandanSNMPtrapwillbe
generated.
Ifaporthasbeendisabledbecauseofexcessivelinkflapping,youcan
resettheporttooperational.
Note: Link flap detection is not supported on Enterasys Matrix X-Series devices.
For information about... Refer to page...
What is Link Flap Detection? 1
Why Would I Use Link Flap Detection in My Network? 1
How Do I Implement Link Flap Detection? 1
Configuring Link Flap Detection 2