Service Interworking; Figure 1-4 Frame Relay To Atm Network Interworking - Cisco BPX 8620 Installation And Configuration Manual

BPX Switch Operation
Figure 1-4
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
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
Relay

Service Interworking

Figure 1-5 shows a typical example of Service Interworking. Service Interworking is supported by the
FRSM on the MGX 8220 and the UFM-C and UFM-U on the IGX switch. Translation between the Frame
Relay and ATM protocols is performed in accordance with RFC 1490 and RFC 1483.
Unlike Network Interworking, in a Service Interworking connection between an ATM port and a Frame
Relay port, the ATM device does not need to be aware that it is connected to an interworking function.
The Frame Relay service user does not implement any ATM specific procedures. Also, the ATM service
user does not need to provide any Frame Relay specific functions. All translational (mapping functions)
are performed by the intermediate interworking function.
This is a typical configuration for service interworking:
•
•
Cisco BPX 8600 Series Installation and Configuration
1-12
Frame Relay to ATM Network Interworking
Inter-
Frame
working
Relay
function
CPE
B-ISDN
FR-SSCS
Inter-
Frame
working
Relay
function
CPE
B-ISDN
FR-SSCS
MGX 8220 Frame Relay (FRSM card) to BPX switch or MGX 8220 ATM port.
IGX switch Frame Relay (FRM-U or FRM-C) to BPX switch or MGX 8220 ATM port.
Chapter 1
Inter-
working
function
ATM network
B-ISDN
FR-SSCS
ATM
ATM network
Release 9.3.30, Part Number 78-12907-01 Rev. E0, May 2005
The BPX Switch: Functional Overview
Frame
Frame
Relay Relay
CPE
CPE
exercises
Frame
appropriate
Relay
SSCS
B-ISDN
FR-SSCS