Cisco Systems 8600 Series manual Frame Relay to ATM Network Interworking

BPX Switch Operation

•MGX 8220 frame relay to IGX switch or IPX switch frame relay (either routing node or shelf/feeder)

Part B of Figure 1-2shows a form of network interworking where the interworking function is performed by only one end of the ATM network, and the CPE connected to the other end of the network must itself perform the appropriate service specific convergence sublayer function. The following are example configurations:

•IGX switch or IPX switch frame relay (either routing node or shelf/feeder) to BPX switch or MGX 8220 ATM port.

•MGX 8220 frame relay to BPX switch or MGX 8220 ATM port.

Network Interworking is supported by the FRP on the IPX switch, the FRM, UFM-C, and UFM-U on the IGX switch, and the FRSM on the MGX 8220. The Frame Relay Service Specific Convergence Sublayer (FR-SSCS) of AAL5 is used to provide protocol conversion and mapping.

Figure 1-2 Frame Relay to ATM Network Interworking

Part A

Network interworking connection from CPE Frame Relay port to CPE Frame Relay port across an ATM Network with the interworking function performed by both ends of the network.

Frame Relay

CPE

Frame Relay

Inter-

working function

B-ISDN FR-SSCS

ATM network

Inter-

working function

B-ISDN FR-SSCS

Frame

Relay

CPE

Frame Relay

Part B

Network interworking connection from CPE Frame Relay port to CPE ATM port across an ATM network, where the network performs an interworking function only at the Frame Relay end of the network. The CPE receiving and transmitting ATM cells at its ATM port is responsible for exercising the applicable service specific convergence sublayer, in this case, (FR-SSCS).

Frame		Frame	Inter-
			working
Relay		Relay
	CPE		function	ATM network
			B-ISDN
			FR-SSCS

CPE

exercises Frame ATM appropriate Relay

SSCS

B-ISDN

FR-SSCS

H8225

1-8Cisco BPX 8600 Series Reference