Methods and apparatus for providing a fast ring reservation arbitration
AssigneePolytechnic University
InventorsHung-Hsiang Jonathan Chao, Alper Altinordu
Life of this patent
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Abstract
In a switch having input ports and output ports, a fast ring reservation arbitration is provided by grouping crosspoint units associated with an output port. If any of the crosspoint units of a group request the output port, a received token will be passed to crosspoint units within the group. If, on the other hand, none of the crosspoint units of a group request the output port, then a received token will bypass the group and be forwarded to a next group.
Claims18
In a switch having input ports, output ports, and a switching fabric for selectively connecting an input port to an output port, the switching fabric including a matrix of crosspoints having rows associated with the input ports and columns associated with the output ports, a method for arbitrating among cells contending for a particular one of the output ports, the method comprising steps of:
- a) for each column of crosspoints, passing a token in a ring defined by the crosspoints;
- b) for each column of crosspoints, defining groups of crosspoints;
- c) for each column of crosspoints and for each of the groups of crosspoints, logically ORing requests for the output port associated with the column to generate a group request;
- d) for each column of crosspoints and for each of the groups of crosspoints, if the group request is LOW, and the token is received, passing received token to a next group of crosspoints in the ring;
- and
- e) for each column of crosspoints and for each of the groups of crosspoints, if the group request is HIGH and the token is received, passing the received token to successive crosspoints of the group of crosspoints,
- wherein, when a crosspoint having a request receives the token, the cell associated with that crosspoint wins the arbitration.
In a switch having input ports, output ports, and a switching fabric for selectively connecting an input port to an output port, the switching fabric including a matrix of crosspoints having rows associated with the input ports and columns associated with the output ports, the columns of crosspoints having groups of crosspoints,
- the first crosspoint of each group having a token input coupled with a first output of a switch and a token output coupled with a token input of a next crosspoint,
- the last crosspoint of each group having a token input coupled with a token output of a preceding crosspoint and a token output coupled with a first input of an OR gate,
- each of the second through next to last crosspoints of each group having a token input coupled with a token output of a preceding crosspoint and a token output coupled with a token input of a next crosspoint,
- a second input of the OR gate coupled with a second output of the switch, and
- an output of the OR gate coupled with the input of a switch of a next group of crosspoint units,
- a method for arbitrating among cells contending for a particular one of the output ports, the method comprising steps of:
- a) for each column of crosspoints and for each of the groups of crosspoints, logically ORing requests for the associated output port to generate a group request;
- and
- b) for each column of crosspoints and for each of the groups of crosspoints, applying the group request as a control signal to the switch,
- wherein, if the group request is LOW, the input of the switch is passed to the second output of the switch, and
- wherein, if the group request is HIGH, the input of the switch is passed to the first output of the switch.
In a system having input ports, output ports, and a switching fabric for selectively connecting an input port to an output port, the switching fabric including a matrix of crosspoints having rows associated with the input ports and columns associated with the output ports, a device comprising:
- a) means, associated with a first group of crosspoints in a column of crosspoints, for accepting a token, for forwarding the token to a next group of forwarding the token to a first crosspoint of the first group in response to a second condition;
- and
- b) means, associated with a second group of crosspoints in a column of crosspoints, for accepting a token from the first group of crosspoints, for forwarding the token to a next group of crosspoints in response to another first condition and for forwarding the token to a first crosspoint of the second group in response to another second condition.
In a system having input ports, output ports, and a switching fabric for selectively connecting an input port to an output port, the switching fabric having a column associated with an output ports, the column comprising:
- a) a first crosspoint group including
- i) a switch having an input for accepting a token, a control input, a first output and a second output,
- ii) an OR gate having a first input coupled with the first output of the switch, a second input, and an output for providing a token,
- iii) a first crosspoint unit having a token input coupled with the second output of the switch and a token output coupled with a next crosspoint unit of the first crosspoint group,
- iv) a last crosspoint unit having a token input coupled with the token output of a preceding crosspoint unit of the first crosspoint group and a token output coupled with the second input of the OR gate, and
- v) switch control logic having an output for providing a control signal to the control input of the switch.
Dependencies are inferred from the claim text.