Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1998-02-19
2001-10-09
Nguyen, Chau (Department: 2663)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S466000
Reexamination Certificate
active
06301251
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to ABR and UBR service in an ATM network. More specifically, the present invention pertains to converting UBR service to ABR service, or ABR service to UBR service with a UBR-ABR gateway.
BACKGROUND OF THE INVENTION
ABR as defined in the ATM Forum standard provides a flow control mechanism intended for non-real time traffic. Implementation of ABR within the network could lead to an efficient utilization of network resources. UBR service, on the other hand, provides a non-controlled flow of non-real time data through the network in a “best effort” mode. For instance, if congestion occurs at some middle switch which causes ATM cells or ATM packets to be dropped at the middle stage switch, then the utilization of these subsequently dropped cells or packets in the preceding switches is wasted. The present invention relates to the mapping of UBR services to ABR service at the edge of the network in order to provide a flow control mechanism for UBR traffic thus yielding an efficient utilization of the network resource. Let the mechanism that maps UBR to ABR to be named as UBR-ABR gateway.
Mapping of UBR traffic to ABR traffic allows an efficient utilization of the network resources. Although ABR services is provided in the forthcoming switches, many adaptor cards and uplink cards at the edge of the network do not have ABR functionality. These hosts at the edge of the network have no choice but to use ABR service for their non-real time data traffic. UBR-ABR gateway, as disclosed, would get the best features of ABR service for UBR traffic generated at the edge of the network. End hosts are not aware of such gateway and they would definitely notice better performance in terms of cell loss and delay.
SUMMARY OF THE INVENTION
The present invention pertains to an ATM communications system. The system comprises an ATM network on which ABR traffic having ABR connections travel and UBR traffic having UBR connections travel. The system comprises a first source node which produces UBR traffic connected to the ATM network. The system comprises a first UBR-ABR gateway which is connected to the ATM network and which receives the UBR traffic and converts the UBR traffic to ABR traffic. The system comprises a second UBR-ABR gateway which is connected to the ATM network and which receives ABR traffic and converts the ABR traffic to UBR traffic. The system comprises a destination node connected to the ATM network which receives the UBR traffic.
The present invention pertains to a UBR-ABR gateway regarding ABR traffic having ABR connections and UBR traffic having UBR connections. The gateway comprises at least one input port for receiving UBR traffic. The gateway comprises a controller which converts the UBR traffic to ABR traffic. The gateway comprises at least one output port for sending the ABR traffic from the switch.
The system comprises a method for sending ABR and UBR traffic over an ATM network. The method comprises the steps of producing UBR traffic having UBR connections at a source node. Then there is the step of sending the UBR traffic to a first UBR-ABR gateway through the ATM network to which the UBR-ABR gateway is connected. Then there is the step of converting the UBR traffic to ABR traffic with a first UBR-ABR gateway. Next there is the step of sending the ABR traffic to a second UBR-ABR gateway through the ATM network to which the second UBR-ABR gateway is connected. Next there is the step of converting the ABR traffic to UBR traffic with the second UBR-ABR gateway. Then there is the step of sending the UBR traffic to a destination node through the ATM network to which the destination node is connected.
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Kim Hyong S.
Vogelsang Stephen J.
Boakye Alexander O.
FORE Systems, Inc.
Nguyen Chau
Schwartz Ansel M.
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