# Presentation: 110143

## TeraVision : a Platform and Software Independent Solution forReal Time Display Distribution inAdvanced Collaborative Environments

- Jason Leigh, Rajvikram Singh, Javier Girado,
- Andrew Johnson, Kyoung Park, Thomas A. DeFanti
- Electronic Visualization Laboratory,University of Illinois at Chicago

## Slide 2

## Goals & Use Scenarios

**Goals & Use Scenarios**

- Docking Problem / Display Pushing Problem
- TeraVision Box (VBox)
- Plug laptop into VBox
- Plug output of an SGI Onyx or PC cluster into VBox

## Advantages of Technique

- It does not require modification of the host visualization software;
- It is compatible with any hardware that can provide a standard VGA or DVI signal;
- It scales to large tiled-displays providing there are sufficient VBoxes and bandwidth to support VBox streams;
- Image generation is decoupled from image capture and transmission- hence the host graphics system can operate at optimal frame rates.

## Hardware Configuration

- 1.5GHz Pentium 4
- NetGear GA620 Gigabit Ethernet NIC
- Foresight I-RGB 75 – 1024x768 @ 60-75Hz – Max 120MB/s sustained transfer rate
- 32 & 64 bit PCI bus
- 32 bit for Foresight
- 64 bit for GigE NIC
- ATI Radeon 8500

## Test Configuration

- VBox

- Receiver

- Windows 2000

- Linux
- Pentium 3- 933MhZ
- Elsa Gloria III Quadra2 Pro

- Cisco 6509 GigE Switch

## Software Implementation

- Frame capture via DMA
- Write to NIC also via DMA
- Software synchronizes transmission on all source nodes & synchronizes receipt at destination nodes
- Ie supports tiled displays
- Software synchronizes end-to-end transmission
- Needed to prevent source from sending quicker than destination can receive
- Currently using TCP for image transfer
- Will switch to Reliable UDP for next implementation- especially for WAN

## Parallel TCP from Chicago to Amsterdam (622Mbps Link)

- Overcoming the Long Fat Network problem
- Basic strategy for GridFTP
- 290-300 parallel sockets – achieved 400Mbps
- Running 2 copies of the application – achieved a total of 550Mbps
- PTCP was practical for lower bandwidths, but the need to open several hundred sockets calls for a more precise solution.
- TCP performs incremental transmit window size and exponential backoff.
- For bulk data transfer over high speed almost-dedicated networks you want the opposite: exponential window size growth with incremental backoff.

**Notes:**
But there is potential for security where you could open socket to different destinations, encrypt them and then de-encrypt them and merge them back.

## General RUDP Algorithm

- Tally upMissing
- packets

- 2. Blast UDP packets
- of entire buffer or data file
- using max useable
- bandwidth

- 1. Use a network probe (like netperf or iperf) to estimate
- Maximum useable UDP bandwidth

## General RUDP Algorithm (cont)

- 4. Blast missing packets
- via UDA

- 3. Send list of missing
- Packets via TCP

## RUDP from Chicago to Amsterdam(622 Mb/s Link) transmitting 100MB

**RUDP from Chicago to Amsterdam****(622 Mb/s Link) transmitting 100MB**

- Max raw UDP rate achieved by iperf – 576Mb/s

- Single default TCP stream – 3Mb/s

**Notes:**
Fake RUDP is best achieveable
Best case is the highest thruput that was achievable
Worst case pure is when 1 retransmit occurred but no rate attenuation was used
Worst case RUDP is when 1 retransmit occurred but rate attenuation was used. Produces smoother performance.

## Performance

- Raw capture frame rate (1024x768x32bit) : 33-35fps via DMA from card to memory
- Max achieved GigE bandwidth from Windows to Linux test – 300Mb/s (optimization needed here- have been able to achieve 900Mb/s in the past in Linux to Linux LAN tests)
- This reduced our display frame rate to 15fps.
- Max remote display frame rate achieved by optimized Linux to Linux streaming (1024x768x24bit) – 30fps

## ToDos

- Bottleneck currently in Windows networking
- Need to apply RUDP for highspeed end-to-end transmission over WAN
- Need to make TeraVision symmetric to allow bi-directional transfer
- Each stream takes 500Mb/s – so reflectors cannot be used for distribution to multiple sites
- Reliable multicasting is needed
- Examine hardware codecs to reduce bandwidth, if necessary

## ToDos

- To increase resolution:
- Foresight I-RGB 200 – 1600x1200 @ 75Hz, 1280x1024 @ 85Hz
- Problem: 1280x1024x32bitx30fps ~ 1Gb/s
- PCI bandwidth is 1Gb/s
- 64 bit PCI is 4Gb/s – 64bit Foresight cards are being planned
- Future??? PCI-X – 8Gb/s, 3GIO/PCI-3 – 48Gb/s

## IGRID 2002

- IGRID – International Grid meeting to demonstrate aggressive network applications (www.startap.net/igrid2002)
- Demonstrate VBox by streaming passive stereo over 2.5G StarLight connection from Chicago to Amsterdam
- AGAVE – Access Grid Augmented Virtual Environment
- GeoWall Consortium (www.geowall.org)

## Dept. Geology and Geophysics, Univ. Minnesota

- Dept. Astronomy, Univ. Minnesota
- Institute for New Media Studies, Univ. Minnesota
- Dept. of Curriculum and Instruction, Univ. Minnesota
- Eros Data Center, US Geological Survey (USGS)
- Dept. of Geological Sciences, Univ. Michigan
- Media Union, Univ. Michigan
- Geological Sciences, Indiana University, Bloomington
- Visualization and Digital Imaging Lab, Univ. Minnesota- Duluth
- Dept. of Computer Science and Mathematics, Fond Du Lac Tribal and Community College
- Northern Arizona Univ.
- Arizona State Univ.

## 2.5G

- AGAVE

- VBox

- VBox

- VBox

- VBox

- DLP

- DLP

- DLP

- DLP

- Left eye image

- Right eye image

- Left eye image

- Right eye image

- Chicago

- Amsterdam

- 2.5Gb/s

## For More Info

- _[www.evl.uic.edu/cavern/continuum](http://www.evl.uic.edu/cavern/continuum)_
- www.evl.uic.edu/cavern/agave
- www.geowall.org