Method and apparatus for adding a randomized propagation delay interval to an interframe spacing in a station accessing an ethernet network
First Claim
1. A method of accessing media of an Ethernet network, comprising:
- sensing deassertion of a receive carrier on the media;
determining a delay time including at least a predetermined interpacket gap interval and a randomized time interval, the randomized time interval randomly selected between and including a propagation delay between two network stations and twice the propagation delay; and
attempting access of the media in response to the sensed deassertion and upon expiration of the determined delay time, wherein the determining step comprises generating the randomized time interval having a duration between and including the propagation delay and twice the propagation delay, the two network stations including a network server and a network client, the propagation delay identifying a cable delay between the network server and the network client.
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Accused Products
Abstract
Delay times are modified in Ethernet network devices by adding a randomized time interval generated in accordance with a propagation delay between two network stations. A server in a client-server arrangement is given priority access over clients by adding to the clients'"'"' InterPacket Gap (IPG) interval a random time delay between one and two times the cable delay between the server and the corresponding client. The server can access the network media after the IPG interval, whereas clients must wait the additional random time delay before accessing the media, thereby improving server throughput and overall network throughput. Collision mediation is improved by adding a randomly selected integer multiple of a propagation delay between two stations, where the integer multiplier is randomly selected from a predetermined range of integers. The randomly selected integer multiple of the propagation delay provides a second dimension of random selection to minimize subsequent collisions and minimize the occurrence of capture effects in losing stations.
47 Citations
27 Claims
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1. A method of accessing media of an Ethernet network, comprising:
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sensing deassertion of a receive carrier on the media; determining a delay time including at least a predetermined interpacket gap interval and a randomized time interval, the randomized time interval randomly selected between and including a propagation delay between two network stations and twice the propagation delay; and attempting access of the media in response to the sensed deassertion and upon expiration of the determined delay time, wherein the determining step comprises generating the randomized time interval having a duration between and including the propagation delay and twice the propagation delay, the two network stations including a network server and a network client, the propagation delay identifying a cable delay between the network server and the network client. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 25)
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2. A network interface for connection with media of an Ethernet network, comprising:
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a carrier sensor sensing deassertion of a receive carrier on the media; a delay time calculator adding a randomized delay interval to a predetermined interpacket gap interval to obtain said delay time, the randomized delay interval randomly selected between one and two times a propagation delay between two network stations; and a media access device attempting access of the media in response to the sensed deassertion of the media and after said delay time. - View Dependent Claims (24, 27)
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14. A method of managing access to a media of an Ethernet network having a server and clients, comprising:
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assigning a first delay time to the server equal to a predetermined interpacket gap interval; enabling the server to access the media in response to deassertion of a receive carrier on the media and after the first delay time; assigning a second delay time to each of the clients equal to the predetermined interpacket gap interval plus a time interval randomly selected with respect to a propagation delay between two network stations; and enabling each of the clients to access the media in response to the deassertion of said receive carrier and after the second delay time. - View Dependent Claims (15, 16, 17)
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18. A method of mediating collisions on media of an Ethernet network, comprising:
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sensing a collision on the media; determining a collision delay interval by multiplying a propagation delay interval representing a maximum propagation delay between two stations on the network with a randomly selected integer from a predetermined range of integers to obtain a randomized delay interval; and attempting access of the media in response to the detected collision and after the collision delay interval. - View Dependent Claims (19, 20, 26)
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21. A method of mediating collisions on media of an Ethernet network, comprising:
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sensing a collision on the media; determining a collision delay interval comprising; (1) randomly selecting a first integer from a predetermined range of integers, (2) randomly selecting a second integer from a second range of integers calculated from an exponential number of access attempts by a network station, (3) multiplying a propagation delay interval representing a maximum propagation delay between two stations on the network with the first integer to obtain a first randomized delay interval, (4) multiplying the second integer with a predetermined slot time to obtain a second randomized delay interval, and (5) adding the first and second randomized delay intervals to obtain the collision delay interval; and attempting access of the media in response to the detected collision and after the collision delay interval. - View Dependent Claims (22, 23)
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Specification