# US 9,521,093 B2 · Optical switching > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,521,093 B2 - Document ID: US9521093B2 - Status: Granted - Kind: B2 - Application number: 13/983,228 - Filed: 2012-01-31 - Published: 2014-12-04 - Granted: 2016-12-13 - Earliest claimed: 2011-02-01 - Assignees: TransPacket AS - Applicants: Steinar Bjornstad; Jan Petter Braute - Inventors: Steinar Bjornstad; Jan Petter Braute - Web page: https://patentgrep.com/patent/US9521093B2 ## CPC - H04Q 11/0066: {Provisions for optical burst or packet networks} - H04B 10/25891: {Transmission components (H04B10/40 takes precedence)} - H04L 47/58: {Changing or combining different scheduling modes, e.g. multimode scheduling} - H04L 47/628: based on packet size, e.g. shortest packet first - H04L 49/3036: {Shared queuing} - H04Q 11/0062: {Network aspects} - H04L 47/564: {Attaching a deadline to packets, e.g. earliest due date first} - H04Q 2011/0064: {Arbitration, scheduling or medium access control aspects} - H04Q 2011/0083: {Testing; Monitoring} - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A network node comprises an optical input, an optical output, a random-access queue and a processing system. It receives a data packet, at the optical input and determines whether to process it as a guaranteed-service packet or as a statistically-multiplexed packet. A guaranteed-service packet is output within a predetermined maximum time of receipt, optionally within a data container comprising container control information. A statistically-multiplexed packet is queued. The node determines a set of statistically-multiplexed packets that would fit a gap between two guaranteed-service packets; selects one of the packets; and outputs it between the two guaranteed-service packets. ## Claims ### Claim 1 A method of processing optical data packets, comprising: receiving a data packet at an optical input; determining whether to process the data packet as a guaranteed-service packet or as a statistically-multiplexed packet; when the data packet is to be processed as a guaranteed-service packet, sending the data packet from an optical output within a predetermined maximum time of receiving the data packet; when the data packet is to be processed as a statistically-multiplexed packet, adding the data packet to a queue that can be accessed randomly in time; and for two outbound guaranteed-service packets, determining a plurality of statistically-multiplexed packets whose lengths are such that each of the plurality of statistically-multiplexed packets would fit in a gap between the two guaranteed-service packets, using a selection process to select a statistically-multiplexed packet from said plurality of statistically-multiplexed packets, and sending the selected statistically-multiplexed packet from the optical output, between the two guaranteed-service packets. ### Claim 2 (depends on 1) The method as claimed in claim 1 wherein the selection process comprises selecting the longest of the plurality of statistically-multiplexed packets that would fit in the gap. ### Claim 3 (depends on 1) The method as claimed in claim 1 comprising sending guaranteed-service packets after a constant, fixed delay from when each of the guaranteed-service packets is received. ### Claim 4 (depends on 1) The method as claimed in claim 1 wherein the queue is an electronic queue and wherein the method further comprises converting a statistically-multiplexed packet from optical to electronic form. ### Claim 5 (depends on 1) The method as claimed in claim 1 wherein each of said plurality of statistically-multiplexed packets is in a different queue. ### Claim 6 (depends on 1) The method as claimed in claim 1 comprising determining said plurality of statistically-multiplexed packets from a candidate set of statistically-multiplexed packets comprising a respective head-of-line packet from each of a plurality of queues. ### Claim 7 (depends on 1) The method as claimed in claim 1 comprising: before sending the selected statistically-multiplexed packet from the optical output, determining a further plurality of statistically-multiplexed packets whose lengths are such that each of the plurality of statistically-multiplexed packets would fit in the gap between the two guaranteed-service packets reduced by the length of the selected statistically-multiplexed packet; selecting a further statistically-multiplexed packet from said further plurality of statistically-multiplexed packets; and sending the plurality of selected statistically-multiplexed packets from the optical output between the two guaranteed-service packets. ### Claim 8 (depends on 1) The method as claimed in claim 1 comprising sending a statistically-multiplexed packet and a guaranteed-service packet on a common wavelength with a common polarisation. ### Claim 9 (depends on 1) The method as claimed in claim 1 comprising adding received guaranteed-service packets to an electronic queue. ### Claim 10 (depends on 1) The method as claimed in claim 1 comprising determining whether any of a plurality of statistically-multiplexed packets in a single queue will fit in a gap between two guaranteed-service packets, and, for a gap large-enough to receive at least one of the statistically-multiplexed packets, inserting the longest statistically-multiplexed packet of the plurality of statistically-multiplexed packets that will fit in the gap. ### Claim 11 A network node comprising an optical input, an optical output, at least one queue that can be accessed randomly in time, and a processing system, wherein the node is configured: to receive a data packet at the optical input; to determine whether to process the data packet as a guaranteed-service packet or as a statistically-multiplexed packet; if the data packet is to be processed as a guaranteed-service packet, to send the data packet from the optical output within a predetermined maximum time of receiving the data packet; if the data packet is to be processed as a statistically-multiplexed packet, to add the data packet to the queue; and for two outbound guaranteed-service packets, to determine a plurality of statistically-multiplexed packets whose lengths are such that each of the plurality of statistically-multiplexed packets would fit in a gap between the two guaranteed-service packets, to use a selection process to select a statistically-multiplexed packet from said plurality of statistically-multiplexed packets, and to send the selected statistically-multiplexed packet from the optical output, between the two guaranteed-service packets. ### Claim 12 (depends on 11) The network node as claimed in claim 11 wherein the selection process comprises selecting the longest of the plurality of statistically-multiplexed packets that would fit in the gap. ### Claim 13 (depends on 11) The network node as claimed in claim 11 configured to send guaranteed-service packets after a constant, fixed delay from when each of the guaranteed-service packets is received. ### Claim 14 (depends on 11) The network node as claimed in claim 11 wherein the queue is an electronic queue and the node is configured to convert a statistically-multiplexed packet from optical to electronic form. ### Claim 15 (depends on 11) The network node as claimed in claim 11 comprising a plurality of queues and configured to determine the plurality of statistically-multiplexed packets such that each of said plurality is in a different queue. ### Claim 16 (depends on 11) The network node as claimed in claim 11 comprising a plurality of queues and configured to determine said plurality of statistically-multiplexed packets from a candidate set of statistically-multiplexed packets comprising the head-of-line packets from said plurality of queues. ### Claim 17 (depends on 11) The network node as claimed in claim 11 configured: before sending the selected statistically-multiplexed packet from the optical output, to determine a further plurality of statistically-multiplexed packets whose lengths are such that each of the plurality of statistically-multiplexed packets would fit in the gap between the two guaranteed-service packets reduced by the length of the selected statistically-multiplexed packet; to select a further statistically-multiplexed packet from said further plurality of statistically-multiplexed packets; and to send the plurality of selected statistically-multiplexed packets from the optical output between the two guaranteed-service packets. ### Claim 18 (depends on 11) The network node as claimed in claim 11 configured to add received guaranteed-service packets to an electronic queue. ### Claim 19 (depends on 11) The network node as claimed in claim 11 configured to determine from which of a plurality of statistically-multiplexed packet queues to insert a statistically-multiplexed packet into the gap, based on a scheduling algorithm that implements any one or more of: fair-queuing, weighted fair-queuing, round-robin, weighted round-robin (WRR), deficit-weighted round-robin (DWRR), and modified deficit round-robin (MDRR). ### Claim 20 (depends on 11) The network node as claimed in claim 11 configured to determine from which of a plurality of statistically-multiplexed packet queues to insert a statistically-multiplexed packet into the gap, based on a scheduling algorithm whose output depends on one or more of: lengths of packets in the queues; a length of the gap; a bandwidth of each queue; and a weight parameter for each queue. ### Claim 21 (depends on 11) The network node as claimed in claim 11, further comprising a fibre delay line and configured to buffer a guaranteed-service packet using the fibre delay line. ### Claim 22 (depends on 11) The network node as claimed in claim 11, wherein the node is an add-drop multiplexer. ### Claim 23 (depends on 11) The network node as claimed in claim 11, wherein the node is part of a plurality of nodes connected by optical connections in an optical network.