Flow control mechanism
First Claim
Patent Images
1. A device for use in a communications network including:
- a housing;
at least two I/O ports connected to the housing;
a switching fabric;
at least one I/O port card operatively coupling the I/O ports to the switching fabric, wherein said at least one I/O port card including logical and electrical circuits for processing frames received from a designated port or to be transmitted to said designated port; and
a Medium Access Controller (MAC) including logical/electrical circuit arrangements generating at least one flow control frame to be used to adjust bandwidth on a link into said device, said at least one flow control frame including a Magic Cookie Field containing information indicating at least one station record field containing information identifying at least one entity causing congestion.
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Accused Products
Abstract
Data bandwidth on a congested link of a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) network, is controlled by a Pause MAC Frame which carries information identifying devices causing the problem on the link. The Recipient of the Pause MAC Frame can use the information to deactivate selected devices on the congested link. As a consequence, the data bandwidth is reduced without shutting down the link.
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Citations
24 Claims
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1. A device for use in a communications network including:
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a housing; at least two I/O ports connected to the housing; a switching fabric; at least one I/O port card operatively coupling the I/O ports to the switching fabric, wherein said at least one I/O port card including logical and electrical circuits for processing frames received from a designated port or to be transmitted to said designated port; and a Medium Access Controller (MAC) including logical/electrical circuit arrangements generating at least one flow control frame to be used to adjust bandwidth on a link into said device, said at least one flow control frame including a Magic Cookie Field containing information indicating at least one station record field containing information identifying at least one entity causing congestion. - View Dependent Claims (2, 3, 4, 5)
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6. A flow control method for use in a network including a communications infrastructure coupling a plurality of Data Terminal Equipments (DTEs) said flow control method including the steps of:
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(a) generating, in a network entity, a Flow Control Frame including a Magic Cookie Field in which information specifying the presence or absence of Station Record Fields is to be placed and Station Record Field for carrying information specifying stations causing congestion; (b) monitoring in said network entity to detect congestion; and (c) inserting, in said flow control frame, appropriate information if congestion is detected. - View Dependent Claims (7, 8, 10, 11, 12, 13)
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9. The method of claim wherein the control field further includes a Validity (V) bit;
Source/Destination (S/D) bit indicating the entity causing the congestion, a G bit indicating shift or no shift, a set of Reserved (RSVRD) bits and a set of bits indicating a period for which a device is to be shut down.
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14. A flow control mechanism for use in a data network including a communications infrastructure coupling a plurality of Data Terminal Equipment (DTE), said flow control mechanism including:
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a circuit arrangement for detecting congestion within said data network; and a controller being responsive to the detection generating a Flow Control Frame including a PAD Field containing a Magic Cookie subfield and an identity of at least one network entity causing the congestion. - View Dependent Claims (15, 16)
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17. A flow control method for use in a communications network including the steps of:
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(a) receiving a frame from a network device; (b) examining the frame; (c) if a field in the frame is set to a first predetermined value, accessing predetermined subfields in said frame; (d) extracting, from said predetermined subfields, information including identity of network devices and pause times for which at least one of the network devices is to be shut down; and (e) using the information to shut down the device. - View Dependent Claims (18, 19)
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20. A mechanism to manage data flow in a CSMA/CD or ethernet network including a Medium Access Controller (MAC) generating a flow control frame including a PAD Field having a first subfield in which information specifying the presence of other subfields is to be placed and at least one of the other subfields specifying network entities causing congestion;
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a transmitter transmitting the flow control frame. - View Dependent Claims (21, 22, 23)
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24. A method for managing flow in a CSMA/CD or ethernet network said method including the acts of receiving in a network entity a MAC frame;
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parsing the MAC frame; if a predetermined value is detected in a particular subfield of said MAC frame, extracting at least one address of a network entity causing congestion; and generating and forwarding another MAC frame to the entity causing the congestion.
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Specification