Layer 2 Switching Commands 660DiffServStandard IP-based networks are designed to provide “best effort” data deliveryservice. Best effort service implies that the network delivers the data in atimely fashion, although there is no guarantee that it will meet the latency orbandwidth requirements. During times of congestion, packets may bedelayed, sent sporadically, or dropped. For typical Internet applications, suchas email and file transfer, a slight degradation in service is acceptable and inmany cases unnoticeable. Conversely, anydegradation of service has undesirable effects on applications with stricttiming requirements, such as voice or multimedia.Diffserv allows the network operator to classify and apply a distinguishedservice to traffic based on a number of criteria. The distinguished service canmeter traffic and apply per hop behavior based upon the bandwidthutilization and burstiness of traffic. In addition, preferential dropcharacteristics can be configured in support of an assured forwardingcapability such that TCP clients are informed if they exceed the switchbuffering limits.Commands in this SectionThis section explains the following commands:assign-queue mark ip-dscp match source-address macshow class-mapclass mark ip-precedence match srcip show classofservicedot1p-mappingclass-map match class-map match srcip6 show classofservice ip-dscp-mappingclass-map rename match cos match srcl4port show classofservicetrustclassofservicedot1p-mappingmatch destination-address macmatch vlan show diffservclassofservice ip-dscp-mappingmatch dstip mirror show diffserv serviceinterface
