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Transcript
The Ideal Network DQSA (Distributed Queue Switch Architecture) Or Routerless Routing and Switchless Switching Presented to Project Rescue Group UCI By Graham Campbell Chief Science Officer Ether2 Corp May 25, 2017 Ether2 Corporation 1 Introduction • DQSA (Distributed Queue Switch Architecture) is a family of protocols developed at The Illinois Institute of Technology. • Basis of DQSA is almost ideal MAC (medium access control) that is effective regardless of speed, distance, or medium. • Ether2 Corp. has acquired the exclusive rights to this patented technology. May 25, 2017 Ether2 Corporation 2 Background of MACs • The telephone party line utilized one of the earlier MACs • • • • which was either good manners or hollering louder. Communications between computers is subject to same economics: – Direct connections often underutilized – A plus - machines, unlike humans, can increase transmission rate. Hollering was no longer a solution. How did computer communications develop? Introduction of Aloha at U of Hawaii in the late 60s started search for ideal MAC. May 25, 2017 Ether2 Corporation 3 Characteristics of the Ideal MAC 1. Immediate Access.* Shared Bus 2. Bus Fully Utilized. 3. Average Delay that of M/D/1 Queue. 4. Delay is Predictable. 5. FIFO with Optional Priorities. 6: Distributed Control - No Master Station.* 7. QoS - Provide Guaranteed Bandwidth. 8. Topology Independent.* 9. Idle Nodes do not use Resources*. 10. Serves geographic area of any size. * Only 1, 6, 8 and 9 supported by Ethernet. May 25, 2017 Ether2 Corporation 4 A Router Has Five Characteristics Output Ports (2) If Traffic Present, Line is Fully Utilized (1) If Line is Empty, Transmit Immediately (5) FIFO Operation with Optional Priorities (4) Delay for Specific Packet is Predictable (3) Average Delay is that of M/D/1 Queue May 25, 2017 Output Buffers Input Buffer Input Ports Ether2 Corporation Arriving Traffic has Poisson Distribution 5 DQSA Has Everything -- How? • DQSA utilizes, in addition to a data slot, three control minislots (CMS) that are used to (1) reserve data slot(s), and (2) resolve contention. DATA SLOT • DQSA utilizes features of existing protocols: – – – – Aloha/CSMA Control Minislots DQDB Stack Protocols: • Next slide compares DQSA with the ideal, note the reasonable delay at 0.95 traffic. May 25, 2017 Ether2 Corporation 6 DQSA Delay M/D/1 - Ideal DQSA 15 12 9 Delay in Slots 6 3 1 0.9 0.7 0.5 0.3 0.1 0 Offered Traffic Load May 25, 2017 Ether2 Corporation 7 COMPARISON OF THROUGHPUT S ( Throughput ) 1 DQSA M/D/1 (Perfect) Non-persistent Slotted CSMA 0.8 Non-persistent CSMA 0.6 0.1 persistent 0.4 1-persistent CSMA CSMA Slotted ALOHA 0.03 persistent CSMA Pure ALOHA 0.2 0.01 May 25, 2017 0.1 1.0 G ( Offered Load ) Ether2 Corporation 10 100 8 PDQSA (Priority DQSA) (Mixture of High and Normal Priority Traffic) Total Load 90% High Normal 0.10 0.80 0.20 0.70 0.30 0.60 0.40 0.50 0.50 0.40 0.60 0.30 0.70 0.20 0.80 0.10 May 25, 2017 Delay in Slots Average High Normal Delay 4.29 9.19 8.64 4.36 9.74 8.54 4.4 10.59 8.53 4.52 11.77 8.55 4.66 13.28 8.49 4.78 15.58 8.38 5.19 19.4 8.35 5.81 28.37 8.41 Ether2 Corporation 9 XDQSA(Extended DQSA) • In the seminal DQSA protocol (DQRAP), each transmission into a CMS is a request to reserve a single dataslot. • In XDQSA each transmission in a CMS is a request to reserve a multiple number of dataslots. • Variable length packets are segmented and the segments (cells) transmitted with no further encapsulation. • Big Plus! XDQRAP requires but two minislots to achieve 100% utilization of dataslots. May 25, 2017 Ether2 Corporation 10 DQSA Segmentation and Transmission IP Datagram – 500 bytes Ethernet Hdr (16 bytes) IP Datagram Encapsulated in Ethernet Frame Ethernet Trlr (4 bytes) IP Datagram Ethernet Frame will be segmented into 520/64 = nine 64-byte chunks. Station transmits request in minislot for nine slots. When request is successful, station joins queue and transmits the nine segments. 64-byte chunk Minislot request from another station May 25, 2017 Ether2 Corporation 11 How Robust is DQSA? • Arrival of multiplicity N is resolved in less than N dataslots ensuring 100% throughput. • Errors in reading CMS and retransmission in CMS do not affect data transmission unless arrival of multiplicity N not resolved in N dataslots. • DQSA can sustain up to 10% error rate in cms before data throughput drops below 1. May 25, 2017 Ether2 Corporation 12 How About QoS? • DQSA provides three general levels of service: 1 Best Effort: Equivalent to conventional transmissions under DQSA where average delay is 8.25 slots at offered traffic of 90%. 2 Priority using PDQ: Delay equivalent to lightly loaded network. PDQ provides ~4 slot delay for 20% high priority in 90% total traffic. 3 Guaranteed Service: DQSA provides equivalent of TDM-like channels intermixed with random access. • DQSA supports intermixed synchronous and asynchronous traffic. May 25, 2017 Ether2 Corporation 13 Why DQSA Works • In networks traffic tends to converge before diverging. Often expensive switches are functioning as congestion prone hubs. • Networks since the time of Bell have been designed to support actual traffic rather than potential traffic. Telcos make best return on investment by selling capacity that is not used, e.g., oversubscribing. • DQSA is the ideal architecture for both of the above – perfect queuing makes for both optimal convergence and for supporting over-subscription. • Let us look at examples. May 25, 2017 Ether2 Corporation 14 A DQSA G.shdsl System DQSA Enhanced G.shdsl Chipset Ether2 Qmux T1 - OC3 Up to 32 ports. Multiple 32-port units can be ganged to a single output port. May 25, 2017 Ether2 QMux -- a DSLAM Replacement at much less cost. Supports QoS. Output speed flexible from T1 to OC3. ATM or IP. Ether2 Corporation 15 Support Voice, Video and Data in Combat UAV can dynamically acquire sync channel Radio tower DQSA achieves 100% utilization of data slots with short transmissions. May 25, 2017 Support of virtually unlimited number of contending users ensures easy tracking of tens of thousands of troops and vehicles. Ether2 Corporation 16 A DQSA SAN Terabyte+ Storage Units 1 Gbps DQSA May 25, 2017 Ether2 Corporation 10 Gigabit/s Backbone DQSA Control 17 DQSA and Cell Systems • Supports up to three times number of calls. • Carrier signaling and spread spectrum. • Dynamically allocated fixedbandwidth channels intermixed with voice packets. • Overloading accommodated . May 25, 2017 Ether2 Corporation Radio tower 18 DQSA Eliminates the Routers San Francisco Denver St. Louis Philadelphia New York Legend HQ DataBase Branch Office Customer Premises Ether2 IAD/NIC Carriers utilize their basic SDH synchronous plant, e.g., T1, DS3, OCx. Customer offices are connected to their respective virtual or physical private networks via Ether2 IADs/NICs. The latter connect directly into the SDH infrastructure. SONET Ring, Central Office May 25, 2017 Ether2 Corporation 19 Ether2 Ethernet-Compatible Cluster DQSA Beacon Generator Passive Fiber Hubs (32 taps) Processor(s) Repeater for Power Budget 1- 10 Gbps Fiber May 25, 2017 Ether2 Corporation 20 Features of DQSA in Clusters • • • • • • Fairness Global Operations Multicast/Broadcast Channels Full utilization with short messages Low Latency Latency (μsecs) 1 Gbps 2 Gbps 5 Gbps 10 Gbps 40 Gbps 4.0 1.6 0.8 0.4 ~4 x Prop Delay (4.5 slots) May 25, 2017 Ether2 Corporation 21 Ease of Implementation • The basic DQSA network consists of a fourstate logic machine at each node. • Sits above the physical layer – any medium, and below the network layer – DQSA just slides in. • A DQSA switch can look like an Ethernet switch, an ATM switch, an IP switch, or any other type of switch. • Potential applications – virtually unlimited. May 25, 2017 Ether2 Corporation Application Transport e.g. TCP TCP Network e.g. IP DQSA Physical 22 CDQ (Cascaded Distributed Queue) Qnodes Fiber Optics Passive Tap Metropolitan/Regional DQSA Networks CDQ utilizes the Qnode. The Qnode provides the equivalent of a routing function by reducing the routing decision to a “yes or no” thus eliminating congestion. Local DQSA networks are “attached” between the Qnodes. May 25, 2017 Ether2 Corporation 23 Conclusion • DQSA represents a paradigm shift in switching. • DQSA will enable final convergence of voice, video and data. • Ether2 has built 12 NICs and two hubs and will be developing software on a prototype 100 Mbps cluster in the next 3 months. • Ether2 is interested in partnering. • Graham Campbell 310.913.4383 [email protected] May 25, 2017 Ether2 Corporation 24