# Presentation: 320219

## Experiences with theQWEST/SCinet Bandwidth Challenge2000-2002

- John Shalf, Wes Bethel
- LBNL

## Slide 2

## Slide 3

## Slide 4

## Slide 5

## Slide 6

## Visapult Architecture

## Visapult Architecture

- 3D

- 2D

## Visapult Architecture

- 3D
- Gigabits

- 2D
- Megabits

## Visapult Architecture

- 3D
- Gigabits

- 2D
- Megabits

## SC2000 Demo Configuration

## SC2000 Network Throughput

## Refactoring the Design

- Congestion avoidance
- Good for internet
- Bad bad baaaad for PVCs and other dedicated networks. (switched lambdas?)
- Multistream TCP
- Erratic performance
- Requires a lot of tuning
- Unfriendly to other users
- Unfriendly to visualization applications
- We want full control of the “throttle”
- Very much like network video

## Refactoring the Design

- TCP is the wrong thing for interactive vis!
- Layer 3 latency/jitter (all buffering effects)
- Poor response to bursty traffic
- Vis needs interactivity and minimal latency!
- Network Video / UDP streams
- Present packets to app. immediately (low latency)
- Full control of data rate
- Lossy, but effects of loss can be managed
- SOCK_RDM

## Effect of Loss on Visapult

- Evolving Binary Black Hole Merger Simulation (100 timesteps)

## SC2001 BWC Testbed

## SC2001 BWC Results

- 3.3 Gigabits Peak (MRTG of ESNet/QWEST OC-48)
- Lots of time spent tuning (packet pacing is nontrivial)

## SC2002 Planning

- Better UDP packet pacing with poor clock granularity
- Error diffusion algorithm from dithering
- Omnidirectional viewing for Visapult
- Nascent Grid Infrastructure
- Global Grid Testbed Collaboration (GGTC)
- GGTC won 3 out of 4 HPC challenge awards

## Global Testbed

## Slide 21

## Bandwidth Scavenging Service

- Czech Republic

- 90% utilization on
-  path from Brno
- To GEANT (to SC)
- via Praha

## Steady @ 16+ Gigabits!

## Slide 24

## Why do we do this??

- Opportunity to test the next generation network capacity (2 years before production)
- Opportunity to test software ideas that will be required to make use of the next generation network (2 year lead)
- Opportunity to test future network engineers (give them a 2 year lead on the problems with future networks)
- Prescient
- I-Way 1995 (presaged vBNS experiences and “The Grid”)
- 1997 multi-stream tests (presaged multi-stream TCP protocols)
- 2001 10GigE and UDP-based protocols
- 10GigE backbone for SC2002
- RUDP, SABUL, TSUNAMI user-space UDP-based protocols

## What should you know for 2003

- Manual throttle (UDP-based protocols) are here to stay.
- Hopefully SOCK_RDM will cover most needs
- Whaaa?  Those idiots are going to burn down the network!  Next big thing: resource management
- RSVP & DiffServ were developed to manage this very situation with regard to network video
- RSVP & DiffServ are never going to happen
- Gregory Bell, “Failure to Thrive: QoS and the Culture of Operational Networking,” *Proceedings of the ACM SIGCOMM 2003 Workshops, RIPQoS Workshop*.
- Next Big Thing? : Pluggable Congestion Management
- AIMD for internet (can even mimic multistream TCP behavior)
- Fixed rate for PVCs and switched lambdas
- Get hints from monitoring services (NWS) to manage flow end-to-end

## Concern about the future of BWC

- The future and eternal reigning champion of the BWC?

## Concern about the future of BWC

- The future and eternal reigning champion of the BWC?
- iperf --udp -b <infinity>

## Concern about the future of BWC

- The future and eternal reigning champion of the BWC?
- How do we prevent this?

## Concern about the future of BWC

- The future and eternal reigning champion of the BWC?
- How do we prevent this?
- There is not technical solution to this problem
- It is a social problem, not a technical one

## Concern about the future of BWC

- The future and eternal reigning champion of the BWC?
- How do we prevent this?
- There is not technical solution to this problem
- Can’t ban UDP
- Can’t eliminate high bandwidth category

## Concern about the future of BWC

- The future and eternal reigning champion of the BWC?
- How do we prevent this?
- There is not technical solution to this problem
- Can’t ban UDP
- Can’t eliminate high bandwidth category
- Must answer
- Does this advance science or art?
- Is this a glimpse of the future?

## Concern about the future of BWC

- The future and eternal reigning champion of the BWC?
- How do we prevent this?
- There is not technical solution to this problem
- Can’t ban UDP
- Can’t eliminate high bandwidth category
- Must answer
- Does this advance science or art?
- Is this a glimpse of the future?
- What the heck are judges for anyways?

## Acknowledgements

- Wes Bethel
- Brian Tierney
- Dan Gunter
- Jason Lee
- Eli Dart
- Mike Bennett
- Chip Smith
- John Christman
- Raju Shah
- Ed Seidel
- Gabrielle Allen
- Tom Goodale
- Thomas Radke
- Mirek Ruda
- Ludek Matskya

-  NERSC
-  LBNL
-  NCSA
-  PSC
-  ANL
-  AEI/Potsdam
-  University of Amsterdam
-  ESNet
-  QWEST
-  Abilene
-  StarLight
-  Teragrid
-  Force10 Networks
-  Scinet

## More Information

- Visapult:
- V1.0: _[http://](http://vis.lbl.gov/projects/visapult)__[vis](http://vis.lbl.gov/projects/visapult)__[.](http://vis.lbl.gov/projects/visapult)__[lbl](http://vis.lbl.gov/projects/visapult)__[.gov/projects/visapult](http://vis.lbl.gov/projects/visapult)_
- V2.0: _[http://vis.lbl.gov/projects/visapult2](http://vis.lbl.gov/projects/visapult2)_
- Cactus
- _[http://www.](http://www.cactuscode.org/)__[cactuscode](http://www.cactuscode.org/)__[.org](http://www.cactuscode.org/)_
- VisPortal *(Grid Portal for managing Visapult)*
- _[http://frost.lbl.gov/visportal/](http://frost.lbl.gov/visportal/)_
- SC2002 Global Grid Testbed
- _[http://scb.ics.muni.cz/static/SC2002/Testbed.html](http://scb.ics.muni.cz/static/SC2002/Testbed.html)_
- Related Publications
- Special Issue on Visualization on the Grid, IEEE Computer Graphics and Applications, Volume 23, Number 2, March/April 2003.