Methods and apparatus for providing quality-of-service guarantees in computer networks

Claim 2

A network for communicating packets of data, comprising: a network medium; a plurality of devices for generating packets of data for transmission on said network medium; and a plurality of device adapters each including: a device interface for connecting to one of said devices and for receiving said packets generated thereby; a network interface for connecting to said network medium; and a processor connected to said interfaces for transmitting said packets received at said device interface to said network interface; said plurality of device adapters creating a frame of time, said frame repeating periodically and including a plurality of time phases; each of said device adapters having at least one of said time phases assigned uniquely thereto and transmitting said packets received at said device interface to said network medium during said time phase assigned thereto; said plurality of time phases including a free-access phase during which each of said device adapters is able to contend for access to the network medium and transmit said packets; and said plurality of device adapters including a master timing device for synchronizing said frame of time in said plurality of device adapters.

Claim 3

A network as claimed in claim 1 wherein said master timing device synchronizes said frame in said plurality of device adapters by sending a fine-resolution frame-sync signal to at least one other said device adapter.

Claim 4

A network as claimed in claim 2 wherein said master timing device compensates for a propagation delay between said master timing device and at least one other said device adapter.

Claim 5

A network as claimed in claim 3 wherein said master timing device determines said propagation delay by measuring a round-trip delay of said frame-sync signal between said master timing device and said other device adapter.

Claim 6

A network as claimed in claim 4 wherein said master timing device estimates a one-way delay between said master timing device and said other device adapter by dividing said round-trip delay by two.

Claim 7

A network as claimed in claim 5 wherein said master timing device compensates for said propagation delay by subtracting said one-way delay from a phase offset within a frame.

Claim 8

A network as claimed in claim 2 wherein said master timing device synchronizes said frame by transmitting a coarse-resolution frame time-stamp packet to at least one other device adapter to align current time.

Claim 9

A network as claimed in claim 1 wherein said master timing device compensates for a propagation delay between said master timing device and at least one other device adapter.

Claim 10

A network as claimed in claim 8 wherein said master timing device determines said propagation delay by receiving a sync-verification signal from said at least one other device adapter and measuring a time offset between said at least one other device adapter and said master timing device.

Claim 11

A network as claimed in claim 9 wherein said master timing device compensates for said propagation delay by transmitting a correction offset value based on said time offset to said at least one other device adapter.

Claim 12

A network as claimed in claim 1 wherein each of said plurality of device adapters includes a crystal oscillator as a time source.

Claim 13

A network as claimed in claim 11 wherein said master timing device synchronizes said frame in said plurality of device adapters by sending a frame-sync signal to at least one other said device adapter to synchronize the frequency of said crystal oscillator thereof.

Claim 14

A network as claimed in claim 1 wherein each of said device adapters has a media access control (MAC) address; said master timing device having the lowest MAC address of said plurality of device adapters.

Claim 15

A network as claimed in claim 1 wherein said plurality of device adapters includes an alternate master timing device which functions as said master timing device when said device connected to said master timing device goes offline.

Claim 16

A network for communicating packets of data, comprising: a network medium; a universal repeater hub including a plurality of ports and a plurality of Ethernet repeater hubs, each of said ports being connected to one of said Ethernet repeater hubs; a plurality of devices for generating packets of data for transmission on said network medium; and a plurality of device adapters each including: a device interface for connecting to one of said devices and for receiving said packets generated thereby; a network interface for connecting to one of said ports of said universal repeater hub via said network medium; and a processor connected to said interfaces for transmitting said packets received at said device interface to said network interface; said plurality of device adapters creating a frame of time, said frame repeating periodically and including a plurality of time phases; each of said device adapters having at least one of said time phases assigned uniquely thereto and transmitting said packets received at said device interface to said network medium during said time phase assigned thereto; said plurality of time phases including a free-access phase during which each of said device adapters is able to contend for access to the network medium and transmit said packets; and at least one of said devices connected directly to one of said ports of said universal repeater hub; and each of said ports of said universal repeater hub connected to one of said device adapters being connected to a first of said Ethernet repeater hubs, and each of said ports of said universal adapter connected directly to one of said devices being connected to a second of said Ethernet repeater hubs.

Claim 17

A network for communicating packets of data, comprising: a network medium; a universal repeater hub including a plurality of ports and a plurality of Ethernet repeater hubs, each of said ports being connected to one of said Ethernet repeater hubs; a plurality of devices for generating packets of data for transmission on said network medium; and a plurality of device adapters each including: a device interface for connecting to one of said devices and for receiving said packets generated thereby; a network interface for connecting to one of said ports of said universal repeater hub via said network medium; and a processor connected to said interfaces for transmitting said packets received at said device interface to said network interface; said plurality of device adapters creating a frame of time, said frame repeating periodically and including a plurality of time phases; each of said device adapters having at least one of said time phases assigned uniquely thereto and transmitting said packets received at said device interface to said network medium during said time phase assigned thereto; said plurality of time phases including a free-access phase during which each of said device adapters is able to contend for access to the network medium and transmit said packets; and at least one of said devices connected directly to one of said ports of said universal repeater hub; and each of said ports of said universal repeater hub connected to one of said device adapters being connected to a first of said Ethernet repeater hubs, and each of said ports of said universal adapter connected directly to one of said devices being connected to a second of said Ethernet repeater hubs.

Claim 18

A network as claimed in claim 15 wherein said universal repeater hub includes a plurality of switches respectively connected to said plurality of ports; each of said switches for connecting a corresponding said port connected to one of said device adapters to said first of said Ethernet repeater hubs and for connecting a corresponding said port connected to directly to one of said devices to said second of said Ethernet devices.

Claim 19

A network as claimed in claim 16 wherein said universal repeater hub includes a processor and a clock source; said processor sending a timing signal from said clock source to each of said ports to determine whether said port is connected to one of said device adapters or connected directly to one of said devices.

Claim 20

A universal repeater hub for connecting a plurality of real-time devices and non-real-time devices into a network, the network including a plurality of device adapters connected to the real-time devices, said universal repeater hub comprising: a plurality of ports each connected to either a device adapter or a non-real-time device; and a plurality of Ethernet repeater hubs; each of said plurality of ports connected to a device adapter being connected to a first of said Ethernet repeater hubs, and each of said plurality of ports connected to a non-real-time device being connected to a second of said Ethernet repeater hubs.

Claim 21

A universal repeater hub for connecting a plurality of real-time devices and non-real-time devices into a network, the network including a plurality of device adapters connected to the real-time devices, said universal repeater hub comprising: a plurality of ports each connected to either a device adapter or a non-real-time device; and a plurality of Ethernet repeater hubs; each of said plurality of ports connected to a device adapter being connected to a first of said Ethernet repeater hubs, and each of said plurality of ports connected to a non-real-time device being connected to a second of said Ethernet repeater hubs.

Claim 22

A universal repeater hub as claimed in claim 18 further comprising a plurality of switches respectively connected to said plurality of ports and to each of said Ethernet repeater hubs; each of said switches for connecting a corresponding said port to either said first Ethernet repeater hub or said second Ethernet repeater hub.

Claim 23

A universal repeater hub as claimed in claim 19 further comprising a processor connected to each of said Ethernet repeater hubs and a clock source connected to said processor.

Claim 24

A universal repeater hub as claimed in claim 20 wherein said processor sends a timing signal from said clock source to each of said ports to determine whether each of said ports is connected to a device adapter or to a non-real-time device; said processor receiving a return signal if a port is connected to a device adapter.

Claim 25

A universal repeater hub as claimed in claim 21 wherein each of said switches connects a corresponding said port to said first Ethernet repeater hub if said port is connected to a device adapter.

Claim 28

A method as claimed in claim 23 wherein said determining step comprises the step of: sending a timing signal to each of said ports; and receiving a return signal from each of said ports connected to a device adapter.

Claim 31

A device adapter as claimed in claim 25 wherein said device adapter is capable of transmitting a signal to other said device adapters connected to the broadcast network for synchronizing said time references other said device adapters connected to the broadcast network.

Claim 34

A method as claimed in claim 27 wherein said synchronizing step comprises the step of: sending a fine-resolution frame-sync signal to at least one other device adapter.

Claim 35

A method as claimed in claim 28 said synchronizing step further comprises the step of: compensating for a propagation delay between said master timing device and said other device adapter.

Claim 36

A method as claimed in claim 29 wherein said compensating step comprises the step of: determining said propagation delay by measuring a round-trip delay of said frame-sync signal between said master timing device and said other device adapter.

Claim 37

A method as claimed in claim 30 wherein said determining step comprises the step of: estimating a one-way delay between said master timing device and said other device adapter by dividing said round-trip delay by two.

Claim 38

A method as claimed in claim 30 wherein said compensating step comprises the step of: subtracting said one-way delay from a phase offset within a frame of said other device adapter.

Claim 39

A method as claimed in claim 27 wherein said synchronizing step comprises the step of: transmitting a coarse-resolution frame time-stamp packet to at least one other device adapter to align current time of said other device adapter.

Claim 40

A method as claimed in claim 27 further comprising the step of: compensating for a propagation delay between said master timing device and at least one other device adapter.

Claim 41

A method as claimed in claim 34 wherein said compensating step comprises the step of: determining said propagation delay with said master timing device by receiving a sync-verification signal from said other device adapter and measuring a time offset between said at least one other device adapter and said master timing device.

Claim 42

A method as claimed in claim 35 wherein compensating step comprises the step of: transmitting a correction offset value based on said time offset to said other device adapter.

Claim 43

A method as claimed in claim 27 wherein each of the device adapters includes a crystal oscillator as a time source, said synchronizing step comprising the step of: sending a frame-sync signal to at least one other said device adapter to synchronize the frequency of said crystal oscillator thereof.

Claim 44

A method as claimed in claim 27 wherein each of the device adapters has a media access control (MAC) address, said designating step comprising the step of: designating said master timing device as the device adapter having the lowest MAC address of the plurality of device adapters.

Claim 45

A method as claimed in claim 27 further comprising the step of: designating an alternate master timing device which functions as said master timing device when a device connected to said master timing device goes offline.

Claim 46

A method as claimed in claim 27 wherein said allowing step comprises the step of: accessing the network medium with a network protocol of carrier sense multiple access with collision detect (CSMA/CD).