Filter
Top Products
Introduction 1-9
BPX Switch Operation
Service Interworking
Figure 1-3 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.
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 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 following is a typical configuration for service interworking:
• 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.
Figure 1-3 Frame Relay to ATM Service Interworking
Additional Information
For additional information about interworking, refer to Chapter 12, Frame Relay to ATM Network
and Service Interworking.
Tiered Networks
Networks may be configured as flat (all nodes perform routing and communicate fully with one
another), or they may be configured as tiered. In a tiered network interface shelves are connected to
routing hubs, where the interface shelves are configured as non-routing nodes.
By allowing CPE connections to connect to a non-routing node (interface shelf), a tiered network is
able to grow in size beyond that which would be possible with only routing nodes comprising the
network.
Starting with Release 8.5, in addition to BPX switch routing hubs, tiered networks now support IGX
switch routing hubs. Voice and data connections originating and terminating on IGX switch interface
shelves (feeders) are routed across the routing network via their associated IGX switch routing hubs.
Intermediate routing nodes must be IGX switches, and IGX switch interface shelves are the only
interface shelves that can be connected to an IGX switch routing hub. With this addition, a tiered
network can now provide a multi-service capability (frame relay, circuit data, voice, and ATM).
ATM network
Service
interworking
function
Frame
Relay
Frame
Relay
ATM
CPE using a
standard, non-
service specific
convergence
protocol
H8226
CPE