Source packet bridge
First Claim
1. A method of implementing a source packet bridge on a network of nodes, comprising:
- providing a node having a first port, the first port having a first time base, a second port, the second port connected to a second bus having a second time base, and an internal interface between the first port and the second port, wherein the first port is connected to a first bus, the first bus having a first cycletimer value, and wherein the second port is connected to a second bus, the second bus having a second cycletimer value that has a time base different than that of the first cycletimer value;
receiving a data stream containing a first set of packets over the first port and extracting a timestamp from a packet, wherein each packet of said first set of packets comprises a plurality of data blocks;
dynamically evaluating a difference between the first cycletimer value and the second cycletimer value;
adjusting the timestamp by adding to it said difference and a latency value;
said latency value being greater than or equal to a predetermined delay value;
said delay value calculated with respect to said second time base;
accumulating data blocks from said first set of packets within an internal (first in first out) FIFO;
packetizing and transmitting a second set of packets over the second port, said second set of packets comprising data blocks retrieved from the internal FIFO; and
wherein the internal FIFO enables packing of a first packet of the second set of packets with data blocks accumulated over a plurality of the first set of packets.
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Accused Products
Abstract
A communication function between ports on a node that does not require a common time base to be distributed across the network is disclosed. A data stream received over a first port is placed on an interlace between nodes using the time base of the first port; a second port samples the data stream on the interface and timestamps it using the time base of the second port. The data stream is timestamped by the second port and packetized before transmitted to the second node to another bridge or device. Alternatively, the first port extracts a time stamp from the data stream and calculates an offset using a cycle timer value from the bus connected to the first port. The offset is added to the cycle timer value on the bus connected to the second port and used to timestamp the data stream.
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Citations
21 Claims
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1. A method of implementing a source packet bridge on a network of nodes, comprising:
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providing a node having a first port, the first port having a first time base, a second port, the second port connected to a second bus having a second time base, and an internal interface between the first port and the second port, wherein the first port is connected to a first bus, the first bus having a first cycletimer value, and wherein the second port is connected to a second bus, the second bus having a second cycletimer value that has a time base different than that of the first cycletimer value; receiving a data stream containing a first set of packets over the first port and extracting a timestamp from a packet, wherein each packet of said first set of packets comprises a plurality of data blocks; dynamically evaluating a difference between the first cycletimer value and the second cycletimer value; adjusting the timestamp by adding to it said difference and a latency value; said latency value being greater than or equal to a predetermined delay value;
said delay value calculated with respect to said second time base;accumulating data blocks from said first set of packets within an internal (first in first out) FIFO; packetizing and transmitting a second set of packets over the second port, said second set of packets comprising data blocks retrieved from the internal FIFO; and wherein the internal FIFO enables packing of a first packet of the second set of packets with data blocks accumulated over a plurality of the first set of packets. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system to re-packetize incoming data encapsulated within one or more packets, the system comprising:
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a first bus operating at a first clock frequency to receive one or more incoming data; a second bus operating at a second clock frequency, different than the first clock frequency, to transmit a modified version of the incoming data as output data; and a latency adjustment module that comprises logic configured to; accumulate data blocks from the one or more incoming data within an internal (first in first out) FIFO; where the internal FIFO is configured to pack a first packet of the output data with data blocks accumulated from the one or more incoming data; transmit the output data over the second bus; wherein the output data comprises an outgoing packing density, the incoming data comprises an incoming packing density, and the incoming packet density and outgoing packing density are substantially different; and wherein the latency adjustment module is further configured to compensate for the substantial difference between the outgoing packing density and the incoming packing density to maintain a substantially constant bandwidth into and out of the system. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A source bridge apparatus, comprising:
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a first bus operating at a first clock frequency to receive one or more incoming data; a second bus operating at a second clock frequency; an internal (first in first out) FIFO, where the internal FIFO is configured to pack a first packet of an output data with data blocks accumulated from the one or more incoming data; a processor; and a computer readable non-transitory storage medium with at least one computer program stored thereon, the at least one computer program configured to, when executed on the processor; accumulate data blocks from the one or more incoming data within the internal FIFO; determine an outgoing packing density and an incoming packing density; and when the incoming packet density and outgoing packing density are substantially different, compensate for the substantial difference between the outgoing packing density and the incoming packing density to maintain a substantially constant bandwidth into and out of the source bridge apparatus. - View Dependent Claims (16, 17, 18, 19, 21)
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20. A method, comprising:
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receiving data packets on a first bus having a first time base; accumulating the received data packets within an internal (first in first out) FIFO; recreating the data packets on the internal FIFO in accordance with the first time base, the internal FIFO being adapted to emulate an application interface associated with a coder/decoder; sampling the data packets from the internal FIFO at a second bus, the second bus being capable of transmitting a full or partially-full packet upon receiving an empty or partially packed isochronous packet from the first bus and maintaining a fixed latency delivery model of the IEEE 61883 transport protocol; stamping with a timestamp associated with a second time base the data packets received from the internal FIFO in response to performance of a dynamic evaluation, the dynamic evaluation comprising an evaluation of each packet of the data packets on the second bus prior to the stamping; and packetizing the stamped and sampled data packets utilizing an IEEE 61883-compliant transport protocol to conform with a minimum and maximum number of data blocks per isochronous period, the minimum and maximum number of data blocks being adapted to be responsive to a number of data blocks received at the first bus, and the maximum number of data blocks that can be packed together; wherein the second bus does not receive synchronization commands from the first bus.
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Specification