Cisco IOS Wide-Area Networking Configuration Guide - Free Books

Configuring Frame RelayConfiguring Frame Relay Traffic ShapingFor examples of configuring Frame Relay traffic shaping, see the section “Frame Relay Traffic ShapingExamples” later in this chapter.Defining VCs for Different Types of TrafficBy defining separate VCs for different types of traffic and specifying queueing and an outbound trafficrate for each VC, you can provide guaranteed bandwidth for each type of traffic. By specifying differenttraffic rates for different VCs over the same line, you can perform virtual time division multiplexing. Bythrottling outbound traffic from high-speed lines in central offices to lower-speed lines in remotelocations, you can ease congestion and data loss in the network; enhanced queueing also preventscongestion-caused data loss.Enabling Frame Relay Traffic Shaping on the InterfaceEnabling Frame Relay traffic shaping on an interface enables both traffic shaping and per-VC queueingon all the PVCs and SVCs on the interface. Traffic shaping enables the router to control the circuit’soutput rate and react to congestion notification information if also configured.To enable Frame Relay traffic shaping on the specified interface, use the following command in interfaceconfiguration mode:CommandRouter(config-if)# frame-relaytraffic-shapingPurposeEnables Frame Relay traffic shaping and per-VC queueing.NoteThe default committed information rate (CIR) of 56K will apply in the following situations:—When traffic shaping is enabled (by using the frame-relay traffic-shaping command), but a map classis not assigned to the VC—When traffic shaping is enabled (by using the frame-relay traffic-shaping command) and a map classis assigned to the VC, but traffic-shaping parameters have not been defined in the map classTo configure a map class with traffic-shaping and per-VC queueing parameters, see the sections“Specifying a Traffic-Shaping Map Class for the Interface” and “Defining a Map Class with Queueingand Traffic-Shaping Parameters”.Frame Relay ForeSightForeSight is the network traffic control software used in some Cisco switches. The Cisco Frame Relayswitch can extend ForeSight messages over a User-to-Network Interface (UNI), passing the backwardcongestion notification for VCs.ForeSight allows Cisco Frame Relay routers to process and react to ForeSight messages and adjust VClevel traffic shaping in a timely manner.ForeSight must be configured explicitly on both the Cisco router and the Cisco switch. ForeSight isenabled on the Cisco router when Frame Relay traffic shaping is configured. However, the router’sresponse to ForeSight is not applied to any VC until the frame-relay adaptive-shaping foresight13