Large Scale WAN Emulation

Martin Arlitt

Rob Simmonds

Carey Williamson

-

University of Calgary

Calgary Alberta

March 18, 2002

Outline

• Overview of WAN Simulation & Emulation

• Introduction to IP-TNE

• Discussion of Related Projects

• Validation of IP-TNE

• Current Projects Involving IP-TNE

• Future Work

1

Performance Evaluation Approaches

1. Experimental

+ offers the most realistic environment

- requires significant financial investment

- can be difficult to repeat results

- restricted to existing technologies

2

Performance Evaluation Approaches

2. Simulation

+ low-cost, flexible, controllable, reproducible environment

- abstractions can compromise usefulness of results

3. Analytical

+ provides quick answers

- often requires the greatest degrees of abstraction

3

Performance Evaluation Approaches

4. Emulation

* a hybrid performance evaluation methodology

* combines aspects of other three approaches

+ enables controlled experimentation with existing applications

- still suffers from drawbacks of other approaches

4

Wide-Area Network Simulation

• provides a virtual Wide-Area Network (WAN) environment

• allows all network conditions to be controlled

– packet loss

– packet reordering/duplication

– link bandwidths

– propogation delays

– asymetric links

– bounded queue sizes

– multipath

• allows alternative networking technologies to be evaluated

5

Wide-Area Network Emulation

• extends capabilities of WAN simulation

• enables controlled testing with unmodified applications

• both simulation and emulation are important tools

6

Challenges

• scaling to large, non-trivial sized networks

• developing realistic models of network characteristics

• keeping pace with real world events (emulator)

7

Introduction to IP-TNE

IP-TNE: Internet Protocol Traffic and Network Emulator

• developed at the University of Calgary

• a collaborative effort between researchers in:

– high performance parallel simulation (Rob)

– IP networking (Carey)

8

Introduction to IP-TNE (cont.)

Design

• built around IP-TN network simulator

• uses a high performance PDES kernel

• kernel modified to provide real-time features

• can simulate end hosts as well

9

Introduction to IP-TNE (cont.)

Operation

• reads packets promiscuously

• replies to ARP requests for registered hosts

• packets timestamped when read from network

• output time calculated by network simulator

• packets released when wall-clock time = output time

10

Introduction to IP-TNE (cont.)

Current Strengths

• high performance

– this enables detailed simulation of non-trivial networks

• flexibility

Current Weaknesses

• simple models of network behaviour

• visualizing operation of large networks

• need for repeatable validation tests

11

Related Projectsns-2

• most well known network simulator/emulator

+ feature rich (e.g., multiple flavours of TCP, etc.)

- poor performance restricts size of simulated network

SSFNet

+ focused on simulating extremely large scale networks

- does not provide emulation capability

12

Related Projects (cont.)Other Network Simulators/Emulators

• dummynet

• NistNet

• Utah Network Testbed

• Network Emulator 4.0

• The Ohio Network Emulator (ONE)

• Opnet

• Shunra Cloud

13

Validation of IP-TNE

Overview

• validation is not a one-time event, but a continuous process

Protocol Implementation

• capture and examine network traffic

e.g., use tcpdump to capture packets between emulator and host

– examine HTTP headers and responses for correctness

– examine IP and TCP headers for correctness

– analyze TCP behaviour for correctness

14

Validation of IP-TNE (cont.)

Emulator Behaviour

• compare application behaviour in real/emulated environments

e.g., Web server benchmarking

– evaluate Web server performance with benchmarking tools

– compare to benchmarking results using IP-TNE

– account for any differences; repeat tests if necessary

– can also compare to results from other emulators

15

Current Projects

Web Server Benchmarking

• demonstrate one use of IP-TNE

• helps validate our emulator (comparing to Nahum et al.)

• show that a centralized approach to WAN emulation:

– can scale to large network sizes

– is more manageable than a distributed approach

16

Current Projects (cont.)

Alberta SuperNet

• what is SuperNet?

– ICT infrastructure throughout province of Alberta

– will provide high-speed Internet access to:

∗ 100% schools

∗ 95% businesses

∗ 80% residences

– 422 communities to be linked

– 5,175 miles of fiber; wireless networks in remote areas

17

Current Projects (cont.)

Alberta SuperNet

• IP-TNE will be used in development of SuperNet

• data captured from SuperNet will be used to:

– develop more realistic models of network conditions for IP-TNE

– validate IP-TNE

• project will test scalability of IP-TNE

18

19

Future Work

• improve models of network conditions

• add additional features (e.g., TCP variants, routing algs)

• make protocol validation a repeatable/automated process

• improve real-time performance of PDES kernel

• participation in SuperNet

• use ELISA (an Internet testbed) to further improve IP-TNE

20

Contact Information

Martin Arlitt: arlitt@cpsc.ucalgary.ca

Rob Simmonds: simmonds@cpsc.ucalgary.ca

Carey Williamson: carey@cpsc.ucalgary.ca

IP-TNE: http://warp.cpsc.ucalgary.ca/

21

2004

NOTE: Not all communities are labelled.

2003

2002

Scheduled Community completion(Calendar Year)

4 February, 2002.

SuperNet Community Rollout Schedule - 2002

Innisfree

Mannville

Mundare

Warburg

Thorsby

Winfield

Buck Lake

Millet

CalmarBeaumont

Breton

DevonNisku

Lindale

Enoch

Eckville

BentleyLeslieville

College HeightsClive

Rocky Mountain House Blackfalds

Alder Flats

Drayton Valley

Sylvan Lake

BenaltoCondor

Fort Saskatchewan

Bruderheim

LamontChipman

2004

NOTE: Not all communities are labelled.

2003

2002

Scheduled Community completion(Calender Year)

SuperNet Community Rollout Schedule

4 February, 2002.

Innisfree

Mannville

Mundare

Warburg

Thorsby

Winfield

Buck Lake

Millet

CalmarBeaumont

Breton

DevonNisku

Lindale

Enoch

Eckville

BentleyLeslieville

College HeightsClive

Rocky Mountain House Blackfalds

Alder Flats

Drayton Valley

Sylvan Lake

BenaltoCondor

Fort Saskatchewan

Bruderheim

LamontChipman

Alexander I.R. 134

EdmontonSt. Albert

Acadia Valley

Acme

Airdrie

Andrew

Ardmore

Ardrossan

Arrowwood

Ashmont

Athabasca

Banff

Barons

Barrhead

Bassano

Bear Canyon

Bearspaw

Beaverlodge

Beiseker

Berwyn

Bezanson

Big Valley

Bindloss

Black Diamond

Blue Ridge

Bluffton

Bonanza

Bowden

Bragg Creek

BrantBrooks

Bruce

Buffalo Head Prairie

Carbon

Carmangay

Carseland

Carstairs

Cereal

Cessford

Champion

Chateh

Chauvin

Clandonald

Cleardale

Clyde

Coalhurst

Dapp

Delia

Dixonville

Donnelly

Duchess

Dunmore

Eaglesham

Edson

Elizabeth Metis SettlementElk Point

Elmworth

Elnora

Entwistle

Exshaw

Fairview

Falun

Fawcett

Flatbush

Fort MacKay

Fort Vermilion

Fox Creek

Gem

Glendon

Grande Cache

Granum

Grovedale

Hanna

Hay Lakes

Hays

Heinsburg

High Level

Hines Creek

Hinton

Horse Lake I.R. 152B

Hussar

Irma

Iron River

Islay

Jasper

Jenner

Keg River

La Crete

Lac La Biche

Lafond

Lloydminster

Lomond

Longview

Manning

Mayerthorpe

Meander River

Mecca Glen

Milo

Morrin

Myrnam

Nampa

Nanton

Olds

Paddle Prairie

Paradise Valley

Peace River

Peers

Penhold

Picture Butte

Rainbow Lake

Rainier

Ralston

Redcliff

Rochester

Rockyford

Rumsey

Rycroft

Schuler

Silver Valley

Smith

Smoky Lake

Stavely

Strathmore

Sturgeon Lake I.R. 154

Sundre

Swan Hills

Teepee Creek

Thorhild

Tilley

Tofield

Valhalla

Vegreville

Vulcan

Wainwright

Wandering River

Wetaskiwin

Woking

Worsley

Youngstown

Zama City

Alliance

Altario

Amisk

Anzac

Atikameg

Barnwell

Bawlf

BellevueBlood I.R. 148

Bodo

Botha

Bow Island

Boyle

Brocket

Brownfield

Buffalo Lake

Cadogan

Cadotte Lake

Cardston

Castor

Chard

Chipewyan Lake

Cold Lake

Conklin

ConsortCoronation

Coutts

Czar

Donalda

Driftpile

Drumheller

East Prairie Metis Settlement

Foremost

Forestburg

Fort Chipewyan

Fort McMurray

Fox Lake

Garden Creek

Glenwood

Grouard

Hardisty

Heart Lake

Killam

Loon Lake

Manyberries

Milk River

New Brigden

Peerless Lake

Rosalind

Sandy Lake

Slave Lake

Tall Cree I.R. 173

Trout Lake

Wabasca-Desmarais

Warner

Wrentham