246 APPENDIX B: PATH BUILDER S330/S310 MODULE AND APPLICATION OVERVIEWFrame Relay ModeFrame relay mode is used to terminate a frame relay router, across the ATMnetwork, for example. This protocol mode converts the frame relay DLCI to aVP/VC ATM connection.A PathBuilder S330/S310 switch provides two interworking features tointerconnect a Frame relay network with an ATM network:n Service Interworkingn Network InterworkingThese interworking features are described in FRF.8 and FRF.5 respectively. Themajor difference between these two features is that there is no FR-SSCS functionrequired for Service Interworking.The following sections describe the details of these two interworking functions aswell as the features provided by the PathBuilder S330/S310 switch.Service Interworking FunctionFigure 177 shows a PathBuilder S330/S310 switch providing Service Interworkingfunction between Frame Relay and ATM services. In this setup, a Frame Relay DTEcommunicates with an ATM DTE, regardless of the fact that there is a differenttype of DTE at each end of the connection.Figure 177 Frame Relay/ATM Service Interworking Connection (FRF.8)ApplicationNull SSCSAAL 5SARATMPHYApplicationPHYQ.922DL CoreNull SSCSAAL 5SARATMPHYPHYQ.922DL CoreATMNetworkFrameRelay DTEATMDTEFrameRelayNetworkFrameRelay DTEATMCellsLAPD FramesApplicationPHYQ.922DL CorePathBuilderS330/S310
