US 7,587,536 B2Granted

Method and apparatus for distributing USB hub functions across a network

AssigneeIcron Technologies Corporation

InventorJohn Alexander McLeod

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Abstract

A method and related apparatuses for data transmission between a host computer and one or a plurality of USB compliant peripheral devices over a data communications network is provided which operates in the presence of transmission delays greater than that normally allowed in the USB specification. The host computer is connected to a local extender device which, in turn, is connected to one or a plurality of remote extender devices through the data communications network. The remote extender devices are, in turn, connected to a plurality of conventional USB peripheral devices. Data between the host computer and peripheral devices is stored and processed in the local and remote extender devices in order to allow the host computer and the USB peripheral devices to operate with greater than normally allowed time delays. In particular, the invention is of most utility when the round-trip transmission delay between the host computer and the USB peripheral device exceeds 1 microsecond.

Claims14

Dependent claims

A method for transmitting data between a host computer and one or a plurality of USB peripheral devices, wherein said USB peripheral devices are distributed around a data communications network and wherein the transmission delay across said network is greater than that normally allowed by the USB specification, said method comprising connecting a host computer to a local extender device, connecting said local extender device to one or a plurality of remote extender devices through a data communication network, and connecting said remote extender devices to one or a plurality of USB peripheral devices, wherein signals between said host computer and said USB peripheral devices are saved, collected, absorbed, or otherwise processed in the local extender and/or the remote extenders so as to allow the host computer and the USB peripheral devices to operate in the presence of a round trip delay greater than that normally allowed in the USB specification, and

wherein said method includes the ability to detect the attachment of a USB peripheral device to the system, to detect the detachment of a USB peripheral device, or includes the ability to determine the network address of a USB function wherein said USB function may be a USB hub or a USB peripheral device, and
wherein said method provides for transmitting a USB command from a host computer, through a local extender, to a unique network address on a data communications network, which method comprises:
a) receiving at a local extender a USB command from a host computer;
b) extracting a first USB address from said USB command;
c) using said first USB address to access a first data record within a table of similar records;
d) determining whether said first data record contains a valid network address;
e) extracting from said first data record a second USB address identifying the upstream USB hub through which said first USB address may be accessed;
f) repeating steps (c) through (e) until a valid network address is found;
g) encapsulating said USB command in a network packet;
h) addressing said network packet to said valid network address;
and
i) transmitting said addressed network packet to said data communications network.

9 more elements

wherein said method provides for conducting asynchronous data transactions, between a host computer and a USB peripheral device, wherein said host computer operates at high-speed and said USB peripheral device operates at classic-speed (full-speed or low-speed), and wherein said data travels in a device to host direction, through a remote extender and a local extender, which method comprises:
a) receiving at a local extender a first request from said host computer for the start of a split data transfer session, having said local extender forward said first request across a network to said remote extender, and then having said local extender generate a negative acknowledgement response to said host computer;
b) receiving at a local extender a subsequent request from said host computer for the start of a split data transfer session and having said local extender continue to generate negative acknowledgement responses to said host computer until said local extender receives a response to said forwarded first request from said remote extender;
c) receiving at a remote extender said forwarded first request for the start of a split data transfer session, having said remote extender convert said forwarded request for the start of a split data transfer session into a classic-speed request for data transfer, and then having said remote extender forward said classic-speed request for data transfer to said USB peripheral device;
d) generating at a remote extender a positive acknowledgement response and forwarding said positive acknowledgement response across a network to said local extender;
e) receiving at a local extender said forwarded positive acknowledgement response and having said local extender store said forwarded positive acknowledgement response in local memory;
f) receiving at a local extender a further request from said host computer for the start of a split data transfer session, having said local extender retrieve from local memory said forwarded positive acknowledgement response, and then having said local extender forward said retrieved positive acknowledgement response to said host computer;
g) receiving at a remote extender a data transfer response from said USB peripheral device and having said remote extender generate a positive acknowledgement response to said USB peripheral device, and then having said remote extender forward said data transfer response across a network to said local extender;
h) receiving at a local extender a first request for completion of a split data transfer session, having said local extender check local memory for the absence of a data transfer response, and then having said local extender generate a not-yet acknowledgement to said host computer;
i) receiving at a local extender said forwarded data transfer response from said remote extender and having said local extender store said forwarded data transfer response in local memory;
and
j) receiving at a local extender a further request for completion of a split data transfer session, having said local extender retrieve from local memory said forwarded data transfer response, and then having said local extender forward said retrieved data transfer response to said host computer.

9 more elements

wherein said method provides for conducting asynchronous data transactions between a host computer and a USB peripheral device, wherein said host computer operates at high-speed and said USB peripheral device operates at classic-speed (full-speed or low-speed), and wherein said data travels in a host to device direction, through a local extender and a remote extender, which method comprises:
a) receiving at a local extender a first notification from said host computer for the start of a split data transfer session, having said local extender forward said first notification across a network to said remote extender, and then having said local extender generate a negative acknowledgement response to said host computer;
b) receiving at a local extender a subsequent notification from said host computer for the start of a split data transfer session and having said local extender continue to generate negative acknowledgement responses to said host computer until said local extender receives a response to said forwarded first notification from said remote extender;
c) receiving at a remote extender said forwarded first notification for the start of a split data transfer session, having said remote extender convert said forwarded notification for the start of a split data transfer session into a classic-speed notification for data transfer, and then having said remote extender forward said classic-speed notification for data transfer to said USB peripheral device;
d) generating at a remote extender a positive acknowledgement response and forwarding said positive acknowledgement response across a network to said local extender;
e) receiving at a local extender said forwarded positive acknowledgement response and having said local extender store said forwarded positive acknowledgement response in local memory;
f) receiving at a local extender a further notification from said host computer for the start of a split data transfer session, having said local extender retrieve from local memory said forwarded positive acknowledgement response, and then having said local extender forward said retrieved positive acknowledgement response to said host computer;
g) receiving at a remote extender a positive acknowledgement response from said USB peripheral device and having said remote extender forward said positive acknowledgement response across a network to said local extender;
h) receiving at a local extender a first request for completion of a split data transfer session, having said local extender check local memory for the absence of a positive acknowledgement response, and then having said local extender generate a not-yet acknowledgement to said host computer;
i) receiving at a local extender said forwarded positive acknowledgement response from said remote extender and having said local extender store said forwarded positive acknowledgement response in local memory;
and
j) receiving at a local extender a further request for completion of a split data transfer session, having said local extender retrieve from local memory said forwarded positive acknowledgement response, and then having said local extender forward said retrieved positive acknowledgement response to said host computer.

9 more elements

wherein said method provides for conducting isochronous data transactions between a host computer and a USB peripheral device, wherein said host computer operates at high-speed and said USB peripheral device operates at classic-speed (full-speed or low-speed), and wherein said data travels in a device to host direction, through a remote extender and a local extender, which method comprises:
a) receiving at a local extender a first request from said host computer for the start of a split data transfer session and having said local extender forward said first request for the start of a split data transfer session across a network to said remote extender;
b) receiving at a local extender a first request for completion of a split data transfer session, having said local extender check local memory for the absence of a complete sequence of split data transfer responses, and then having said local extender generate a null data response to said host computer;
c) receiving at a remote extender said forwarded first request for the start of a split data transfer session, having said remote extender convert said forwarded request for the start of a split data transfer session into a classic-speed request for data transfer, and then having said remote extender forward said classic-speed request for data transfer to said USB peripheral device;
d) receiving at a remote extender a data transfer response from said USB peripheral device and having said remote extender convert said received data transfer response into a sequence of split data transfer responses, and then having said remote extender forward said sequence of split data transfer responses across a network to said local extender;
e) receiving at a local extender said forwarded sequence of split data transfer responses from said remote extender and having said local extender store said forwarded sequence of split data transfer responses in local memory;
f) receiving at a local extender a subsequent request from said host computer for the start of a split data transfer session and having said local extender forward said subsequent request across a network to said remote extender;
and
g) receiving at a local extender a sequence of subsequent requests for completion of a split data transfer session, having said local extender check local memory for the presence of a complete sequence of split data transfer responses, and then having said local extender retrieve said sequence of split data responses from memory and forward said sequence of split data responses to said host computer.

6 more elements

wherein said method provides for conducting isochronous data transactions between a host computer and a USB peripheral device, wherein said host computer operates at high-speed and said USB peripheral device operates at classic-speed (full-speed or low-speed), and wherein said data travels in a host to device direction, through a local extender and a remote extender, which method comprises:
a) receiving at a local extender a notification from said host computer for the start of a split data transfer session, having said local extender forward said notification for the start of a split data transfer session across a network to said remote extender, and then having said remote extender store said notification for the start of a split data transfer session in local memory;
b) receiving at a local extender a first notification from said host computer for the continuation of a split data transfer session, having said local extender forward said first notification for the continuation of a split data transfer session across a network to said remote extender, and then having said remote extender store said first notification for the continuation of a split data transfer session in local memory;
c) receiving at a local extender a further notification from said host computer for the continuation of a split data transfer session, having said local extender forward said further notification for the continuation of a split data transfer session across a network to said remote extender, and then having said remote extender store said further notification for the continuation of a split data transfer session in local memory;
d) receiving at a local extender a notification from said host computer for the completion of a split data transfer session, having said local extender forward said notification for the completion of a split data transfer session across a network to said remote extender, and then having said remote extender store said notification for the completion of a split data transfer session in local memory;
e) assembling at a remote extender said stored notification for the start of a split data transfer, said stored first notification for the continuation of a split data transfer, said stored further notification for the continuation of a split data transfer and said stored notification for the completion of a split data transfer session into a classic-speed notification of data transfer;
and
f) having said remote extender forward said classic-speed notification of data transfer to said USB peripheral device.

5 more elements

Dependencies are inferred from the claim text.