Method and apparatus for implementing a backpressure mechanism in an asynchronous data transfer and source traffic control system
AssigneeTranSwitch Corporation
InventorsRonald P. Novick, Sing Ngee Yeo
Life of this patent
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Abstract
Methods for implementing a backpressure mechanism in an asynchronous data transfer and source traffic control system include detecting when a bus user is experiencing congestion and preventing other bus users from sending cells over the bus. According to a first embodiment, if congestion is detected for two consecutive frames, the arbiter is inhibited from granting access to any bus user for one frame. According to a second embodiment, if congestion is detected during any frame, all the bus users are prevented from transmitting low priority traffic until congestion is absent for four consecutive frames. An apparatus for performing the methods is also disclosed
Claims21
A method for implementing a backpressure mechanism in an asynchronous data transfer and source traffic control system having a data bus and a plurality of bus users where data is transferred over the bus in a repeating frame, said method comprising:
- a) detecting a congestion condition in one of the bus users;
- and
- b) barring access to the bus for one frame following the detection of a congestion condition.
A method for implementing a backpressure mechanism in an asynchronous data transfer and source traffic control system having a data bus and a plurality of bus users where data is transferred over the bus in a repeating frame, some data is high priority and other data is low priority, said method comprising:
- a) detecting a congestion condition in one of the bus users;
- and
- b) barring low priority data access to the bus following the detection of a congestion condition.
An apparatus for implementing a backpressure mechanism in an asynchronous data transfer and source traffic control system having a data bus and a plurality of bus users where data is transferred over the bus in a repeating frame, said apparatus comprising:
- a) detection means for detecting a congestion condition in one of the bus users;
- and
- b) access control means for barring access to the bus for one frame following the detection of a congestion condition.
The apparatus according to claim 23, wherein:
- the system includes a bus master coupled to the bus,
- the bus users request access to the bus at the beginning of the frame, and
- the bus master grants access at the end of the frame.
An apparatus for implementing a backpressure mechanism in an asynchronous data transfer and source traffic control system having a data bus and a plurality of bus users where data is transferred over the bus in a repeating frame, some data is high priority and other data is low priority, said method comprising:
- a) detection means for detecting a congestion condition in one of the bus users;
- and
- b) access control means barring low priority data access to the bus following the detection of a congestion condition.
Dependencies are inferred from the claim text.