3Com S330 manual DCE Allows DTE to Participate in ATM Network through ATM DXI

Serial Interface 217

Through ATM DXI, the DCE allows the DTE to participate in an ATM network. (See Figure 157.)

Figure 157 DCE Allows DTE to Participate in ATM Network through ATM DXI

DTE SDU

DXI Data Link

DXI Physical

DTE

	DTE SDU
			AAL 5 CPCS
	DXI Data Link
			AAL 5 SAR
			ATM
	DXI Physical		UNI Physical
DXI				UNI
		DCE

DXI Mode 1A is designed to allow legacy routers to utilize frame-based transmission to transmit an ATM network to the DXI Mode 1A device (PathBuilder S330/S310 serial interface), which then will perform SAR and AAL5 mapping to an ATM PVC. It provides simple and efficient encapsulation of your service data unit and supports AAL5 transit encapsulation. (See Figure 158.)

Figure 158 DXI Format Mode 1A

DTE SDU

DTE Service Data Unit

	Error Check
DTE to DSU
			Flag	FCS			Data	DXI Information		Flag
DXI Frame
Octet		1		2		0-9232		2		1
DSU to ATM											DSU
					AAL 5 CPCS-PDU					01111110
Network
Translation										Address Maps
AAL 5			SAR-PDU
										to/from VPI/VCI
SAR							SAR-PDU
									SAR-PDU
DXI Protocol Mode 1A									ATM Cell