September 16, 2015Ether2 Corporation1 DQSA DQSA (Distributed Queue Switch Architecture) Or...

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


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.


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.


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.


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


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


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


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


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


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.


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


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.


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.


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.


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.


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


A DQSA SAN

10 G

igab

it/s

Bac

kbon

e

Terabyte+ Storage Units DQSA Control

1 Gbps DQSA


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


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


Ether2 Ethernet-Compatible Cluster

DQSA Beacon Generator

1- 10 Gbps Fiber

Repeater for Power Budget

Passive Fiber Hubs(32 taps)

Processor(s)


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


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


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.


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]

September 16, 2015Ether2 Corporation1 DQSA DQSA (Distributed Queue Switch Architecture) Or...

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