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US 6,377,579 B1Granted
Interconnecting a synchronous switching network that utilizes a common time reference with an asynchronous switching network
AssigneeSynchrodyne Networks, Inc.
InventorYoram Ofek
Life of this patent
Estimating the term…
Abstract
This invention describes a method for exchanging timing messages and data packets between switches of a network with a common time reference, and between end stations and switches of such a network, over an asynchronous sub-network. The method entails transmission of messages conveying the common time reference, and data packets that are sent responsive to the timing information and predetermined scheduled time intervals. The switches of the network maintain a common time reference, which is obtained either from an external source (such as GPS-Global Positioning System) or is generated and distributed internally. The time intervals are arranged in simple periodicity and complex periodicity (like seconds and minutes of a clock).
Claims49
A system for transferring data packets from at least one end-station to a data communications network, the system comprising:
- a plurality of synchronous virtual pipe switches, each having a plurality of input ports and a plurality of output ports, each with a unique address;
- wherein a common time reference signal is coupled to each of the synchronous virtual pipe switches;
- a plurality of asynchronous switches, each having a plurality of input ports and a plurality of output ports, each with a unique address;
- interconnected communication links in a path in the network for connecting the end-station to the synchronous virtual pipe switch through the plurality of asynchronous switches;
- wherein there is a defined delay between the end-station and a first one of the synchronous virtual pipe switches;
- wherein each of said data packets has a pipe identification (PID);
- wherein the transfer of the data packet is provided during respective ones of a plurality of time intervals, wherein each of the time intervals is comprised of a plurality of time frames;
- and
- a delay analysis and scheduling controller for determining, for each of the synchronous virtual pipe switches, a first scheduled time within a first predefined time frame within which a respective one of the data packets is scheduled for transfer out of the respective synchronous virtual pipe switch.
6 more elements
A system for transferring data packets, each having a pipe identification (PID) field, through a data communications network, the system comprising:
- a plurality of synchronous virtual pipe switches, each having a plurality of input ports and a plurality of output ports, each with a unique address;
- a common time reference signal coupled to each of the synchronous virtual pipe switches;
- a plurality of asynchronous switches, each having a plurality of input ports and a plurality of output ports, each with a unique address;
- interconnected communication links in a path in the network for connecting a first of the synchronous virtual pipe switches to a second of the synchronous virtual pipe switches through a plurality of the asynchronous switches;
- wherein there is a defined delay in the transfer of respective ones of the data packets between the first synchronous virtual pipe switch and the second synchronous virtual pipe switch;
- wherein the first synchronous virtual pipe switch records the time of arrival (TOA) for each said separate packet responsive to receiving the respective data packet from the second synchronous virtual pipe switch;
- wherein the transfer of the respective data packet is provided during respective ones of a plurality of time intervals, wherein each of the time intervals is comprised of a plurality of time frames;
- a delay analysis and scheduling controller for determining for each synchronous virtual pipe switch a first scheduled time within a first predefined time frame within which a respective data packet is scheduled to be transferred out of the respective synchronous virtual pipe switch responsive to the PID field.
5 more elements
A system for transferring data packets from at least one end-station to a data communications network, the system comprising:
- an asynchronous to synchronous gateway having a plurality of input ports and a plurality of output ports, each with a unique address;
- a common time reference signal coupled to each of the asynchronous to synchronous gateways;
- an asynchronous switch having a plurality of input ports and a plurality of output ports, each with a unique address;
- interconnected communication links in a path in the network for connecting the end-station to the asynchronous to synchronous gateway through a plurality of asynchronous switches;
- wherein there is a defined delay for transfer of the data packets between the end-station and the first asynchronous to synchronous gateway;
- wherein the asynchronous to synchronous gateway receives data packets from the end-station and separately records the time of arrival (TOA) for each of said data packets;
- wherein each said data packet has a pipe identification (PID);
- wherein the transfer of the data packet is provided during respective ones of a plurality of time intervals, wherein each of the time intervals is comprised of a plurality of time frames;
- a delay analysis and scheduling controller for determining for each asynchronous to synchronous gateway a first scheduled time within a first predefined time frame within which a respective data packet is scheduled to be transferred out of the respective asynchronous to synchronous gateway responsive to the PID and TOA associated with the respective data packet.
6 more elements
A system for transferring data packets from at least one end-station to a data communications network, the system comprising:
- a plurality of synchronous virtual pipe switches, each having a plurality of input ports and a plurality of output ports, each with a unique address;
- an asynchronous switch having a plurality of input ports and a plurality of output ports, each with a unique address;
- interconnected communication links in a path in the network for connecting the end-station to the synchronous virtual pipe switch through the asynchronous switch;
- wherein there is a defined delay for transfer of the respective data packets between the end-station and a first one of the synchronous virtual pipe switches;
- a common time reference signal coupled to each of the synchronous virtual pipe switches;
- wherein the common time reference is partitioned into time frames;
- wherein a predefined number of contiguous k time frames are grouped into a time cycle;
- wherein k is at least 1;
- wherein a predefined number of contiguous l time cycles are grouped into a super cycle;
- wherein l is at least 1;
- wherein each of said synchronous virtual pipe switches is comprised of a routing controller with a routing table, for selecting at least one of the output ports that said data packets will be forwarded to;
- wherein the routing controller attaches a time of arrival (TOA) to respective ones of the data packets;
- wherein the time of arrival is derived from the common time reference and is represented as a time frame number within a time cycle and as time cycle number within a super cycle;
- a switching fabric in each of the synchronous virtual pipe switches;
- a delay analysis and scheduling controller, for determining for each of the synchronous virtual pipe switches, a first scheduled time within a first predefined time frame within which a respective one of the data packets is scheduled to be transferred out of the respective synchronous virtual pipe switch;
- a random access memory, partitioned into plurality of buffers, in each of the synchronous virtual pipe switches;
- and
- a select buffer controller in each of the synchronous virtual pipe switches, for selecting one of the buffers for output.
15 more elements
Dependencies are inferred from the claim text.