Specifications

Quality of Service Overview
May 09, 2011 Page 11 of 38
Figure 4 Hybrid Queuing Packet Behavior
Rate Limiting
Ratelimitingisusedtocontroltherateoftrafficentering(inbound)and/orleaving(outbound)a
switchperCoS.Ratelimitingallowsforthethrottlingoftrafficflowsthatconsumeavailable
bandwidth,intheprocessprovidingroomforotherflows.Ratelimitingguaranteesthe
availabilityofbandwidthforothertrafficby
preventingtheratelimitedtrafficfromconsuming
morethantheassignedamountofanetwork’sresources.Ratelimitingaccomplishesthisby
settingacaponthebandwidthutilizationofspecifictypesofbothinbou n d andoutboundtraffic.
Whenaratelimithasbeenexceeded,theCoScanbeconfiguredto
performoneorallofthe
following:recordaSyslogmessage,sendanSNMPtraptoinformtheadministrator,and
automaticallydisabletheport.
Figure 5onpage 12illustrateshowburstytrafficisclippedabovetheassignedthresholdwithrate
limitingapplied.