Frame Relay to ATM Network and Service Interworking 12-3
Service Interworking
Figure 12-3 Frame Relay to ATM Interworking Examples with AIT Card on IPX Switch
Service Interworking
In Service Interworking, for example, for a connection between an ATM port and a frame relay port,
unlike Network Interworking, the ATM device does not need to be aware that it is connected to an
interworking function. The ATM device uses a standard service specific convergence sublayer,
instead of using the Frame Relay FR-SSCS (see Figure 12-4).
The frame relay service user does not implement any ATM specific procedures, and the ATM service
user does not need to provide any frame relay specific functions. All translational (mapping
functions) are performed by the intermediate IWF. The ATM endpoints may be any ATM UNI/NNI
S5239
Frame
Relay
Frame
Relay
Frame
Relay
Frame
Relay
Frame
Relay
FRP ASIBNIAIT
One of these must be
an IPX interface shelf
IPX
IPX to BPX
IPX cloud to BPX
IPX to (IPX - BPX cloud) to BPX The AIT-BNI trunks are always CGW
Frame relay IPX to frame relay IPX
BPX
AIT Interworking Examples
CPE
FRP
BNIBNI
AIT
IPX BPX
AXIS
shelf
Fr Rly
FRP
FRP
BNI BNI
AIT
AIT
IPX BPX BPX
FRP
ASIBNI
AIT
IPX IPX CPEBPX
IPX
interface
shelf
FRP
BNI AIT
AIT
BNI ASI
IPX
BPX BPX
IPX BPX
CPE
BPX
