Cisco Systems 8600 Series manual Networking Interworking

Networking Interworking

interface supported by the MGX 8220, e.g., ASI, AUSM. Translation between the Frame Relay and ATM protocols is performed in accordance with RFC 1490 and RFC 1483.

Figure 12-4 Frame Relay to ATM Service Interworking Detail

				AXIS Shelf			B - CPE
				BNM		AUSM	Upper
							layers
B - CPE		BPX					CPCS
Upper	ASI	BNI					SAR
layers				ATM		ATM	ATM
		ATM T3/E3	Physical			Physical	Physical
CPCS		(feeder trunk)
SAR							ATM T1/E1
ATM	ATM	ATM
Physical	Physical	Physical
ATM T3/E3		AXIS shelf
		BNM				FRSM	FR CPE
		ATM T3/E3			RFC 1483 RFC 1490		Upper
							layers
		(feeder trunk)			Null SSCS Q.922		Q.922
					AAL-5
		ATM			ATM
	ATM NW	Physical			Physical	Physical	Physical

	Frame Relay
Frame Relay CPE connected to B-ISDN CPE	Narrowband NW

S5236

Networking Interworking

In Network Interworking, in most cases, the source and destination ports are frame relay ports, and the interworking function is performed at both ends of the connection as shown in Part A of Figure 12-5.

If a frame relay port is connected across an ATM network to an ATM device, network interworking requires that the ATM device recognize that it is connected to an interworking function (frame relay, in this case). The ATM device must then exercise the appropriate service specific convergence sublayer (SSCS), in this case the frame relay service specific convergence sublayer (FR-SSCS) as shown in Part B of Figure 12-5.

12-4Cisco BPX 8600 Series Reference