Figure 18.5 FRAD X.25 X.25 ATM FRAD Frame FRAD Relay ATM PPP PPP FRAD,Frame Relay Assembler dissembler, 帧中继组装器/分解器 18.1018.10 Figure 18.5 FRAD FRAD，Frame Relay Assembler / dissembler, 帧中继组装器/分解器