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April 19, 2023 Ether2 Corporation 1
DQSADQSA(Distributed Queue Switch Architecture)(Distributed Queue Switch Architecture)
OrOr
Routerless Routing and Switchless SwitchingRouterless Routing and Switchless Switching
Presented to Project Rescue GroupPresented to Project Rescue GroupUCIUCI
ByBy
Graham CampbellGraham CampbellChief Science OfficerChief Science Officer
Ether2 CorpEther2 Corp
The Ideal Network
April 19, 2023 Ether2 Corporation 2
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.
April 19, 2023 Ether2 Corporation 3
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.
April 19, 2023 Ether2 Corporation 4
Characteristics of the Ideal MAC
1. Immediate Access.*
2. Bus Fully Utilized.
3. Average Delay that of M/D/1 Queue.
4. Delay is Predictable.
5. FIFO with Optional Priorities.
Shared Bus
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.
April 19, 2023 Ether2 Corporation 5
A Router Has Five Characteristics
Output Ports
Input Ports
Input Buffer
(1) If Line is Empty, Transmit
Immediately
(2) If Traffic Present, Line is
Fully Utilized
(3) Average Delay is that of M/D/1
Queue
(4) Delay for Specific Packet is
Predictable
(5) FIFO Operation with Optional
Priorities
Output Buffers
Arriving Traffic has Poisson Distribution
April 19, 2023 Ether2 Corporation 6
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.
• 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.
DATA SLOT
April 19, 2023 Ether2 Corporation 7
DQSA Delay
Offered Traffic Load
0
3
6
9
12
150.1
0.3
0.5
0.7
0.9 1
Delay in Slots
M/D/1 - IdealDQSA
April 19, 2023 Ether2 Corporation 8
COMPARISON OF THROUGHPUT
G ( Offered Load )
0.01 0.1 1.0 10 100
S ( Throughput )
1
0.8
0.6
0.4
0.2
ALOHA
Pure ALOHA
Slotted1-persistent
CSMA0.03 persistent
CSMA
0.1 persistentCSMA
Non-persistentCSMA
Non-persistentSlotted CSMA
M/D/1(Perfect)
DQSA
April 19, 2023 Ether2 Corporation 9
PDQSA (Priority DQSA) (Mixture of High and Normal Priority Traffic)
Total Load 90% Delay in Slots AverageHigh Normal High Normal Delay0.10 0.80 4.29 9.19 8.640.20 0.70 4.36 9.74 8.540.30 0.60 4.4 10.59 8.530.40
0.50 4.52 11.77 8.550.50 0.40 4.66 13.28 8.490.60 0.30 4.78 15.58 8.380.70 0.20 5.19 19.4 8.350.80 0.10 5.81 28.37 8.41
April 19, 2023 Ether2 Corporation 10
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.
April 19, 2023 Ether2 Corporation 11
DQSA Segmentation and Transmission
Minislot request from another
station
IP Datagram – 500 bytes
IP Datagram
Ethernet Hdr(16 bytes)
Ethernet Trlr(4 bytes)
IP Datagram Encapsulated in Ethernet Frame
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
April 19, 2023 Ether2 Corporation 12
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.
April 19, 2023 Ether2 Corporation 13
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.
April 19, 2023 Ether2 Corporation 14
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., over-subscribing.
• 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.
April 19, 2023 Ether2 Corporation 15
A DQSA G.shdsl System
T1 - OC3
Ether2 Qmux
DQSA Enhanced G.shdsl Chipset
Ether2 QMux -- a DSLAM Replacement at much lesscost. Supports QoS. Output speed flexible from T1
to OC3. ATM or IP.
Up to 32 ports. Multiple 32-port units can be gangedto a single output port.
April 19, 2023 Ether2 Corporation 16
Support Voice, Video and Data in Combat
DQSA achieves 100% utilization of data slots with
short transmissions.
Support of virtually unlimited numberof contending users ensures easy tracking of
tens of thousands of troops andvehicles.
Radio tower
UAV can dynamically acquire sync channel
April 19, 2023 Ether2 Corporation 17
A DQSA SAN
10 G
igab
it/s
Bac
kbon
e
Terabyte+ Storage Units DQSA Control
1 Gbps DQSA
April 19, 2023 Ether2 Corporation 18
DQSA and Cell Systems
• Supports up to three times number of calls.
• Carrier signaling and spread spectrum.
• Dynamically allocated fixed-bandwidth channels intermixed with voice packets.
• Overloading accommodated .
Radio tower
April 19, 2023 Ether2 Corporation 19
DQSA Eliminates the Routers
New YorkSan Francisco Denver St. Louis Philadelphia
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.
Customer Premises Ether2 IAD/NIC
Legend
HQ DataBase
Branch Office
SONET Ring, Central Office
April 19, 2023 Ether2 Corporation 20
Ether2 Ethernet-Compatible Cluster
DQSA Beacon Generator
1- 10 Gbps Fiber
Repeater for Power Budget
Passive Fiber Hubs(32 taps)
Processor(s)
April 19, 2023 Ether2 Corporation 21
Features of DQSA in Clusters
• Fairness• Global Operations• Multicast/Broadcast• Channels• Full utilization with short messages• Low Latency
1 Gbps 2 Gbps 5 Gbps 10 Gbps 40 Gbps
Latency (μsecs) (4.5 slots)
4.0 1.6 0.8 0.4 ~4 x Prop Delay
April 19, 2023 Ether2 Corporation 22
Ease of Implementation
• The basic DQSA network consists of a four-state 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.
Transport e.g. TCPTCP
Application
DQSA
Physical
Network e.g. IP
April 19, 2023 Ether2 Corporation 23
Qnodes
M etropo litan/RegionalDQSA Networks
Fiber OpticsPassive Tap
CDQ (Cascaded Distributed Queue)
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.
April 19, 2023 Ether2 Corporation 24
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