coopnet cooperative networking
Download
Skip this Video
Download Presentation
CoopNet: Cooperative Networking

Loading in 2 Seconds...

play fullscreen
1 / 21

CoopNet: Cooperative Networking - PowerPoint PPT Presentation


  • 233 Views
  • Uploaded on

CoopNet: Cooperative Networking. Phil Chou, Venkat Padmanabhan, Helen Wang September 17, 2002. Motivation. “Flash crowd” can overwhelm server often due to news event of widespread interest… … but not always (e.g., Webcast of birthday party)

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'CoopNet: Cooperative Networking' - Samuel


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
coopnet cooperative networking

CoopNet: Cooperative Networking

Phil Chou, Venkat Padmanabhan, Helen Wang

September 17, 2002

motivation
Motivation
  • “Flash crowd” can overwhelm server
    • often due to news event of widespread interest…
    • … but not always (e.g., Webcast of birthday party)
    • can affect relatively obscure sites (e.g., election.dos.state.fl.us, firestone.com, nbaa.org)
    • affects Web content as well as streaming content (live and on-demand)
    • infrastructure-based CDNs aren’t for everyone
  • Goal: solve the flash crowd problem!
cooperative networking
Cooperative Networking

CoopNet

Client-server

Pure peer-to-peer

  • CoopNet complements client-server system
    • Client-server operation in normal times
    • P2P content distribution invoked on demand to alleviate server overload
    • Clients participate only while interested in the content
    • Server still plays a critical role
research activities
Research Activities
  • Web flash crowd alleviation (with Kay Sripanidkulchai)
    • evaluation using Sep 11 traces from MSNBC
    • prototype implementation done
    • paper @ IPTPS ’02
  • MDC-based streaming media distribution
    • evaluation using Sep 11 traces from MSNBC, Akamai, Digital Island
    • implementation in progress
    • paper @ NOSSDAV ’02
    • patent process in progress
    • initial discussions with Digital Media Division
research activities contd
Research Activities (contd.)
  • PeerMetric (with Karthik Lakshminarayanan)
    • characterize broadband network performance
    • P2P as well as client-server performance
    • working with Xbox Online (Mark VanAntwerp)
    • deployment on ~25 distributed nodes underway
    • eventual deployment on ~300 Xbox Live beta users
  • Future directions
    • CoopNet in a Wireless Mesh Network
    • good synergy: saves Internet bandwidth, improves robustness
robustness of live streaming
Robustness of Live Streaming
  • Peers are not dedicated servers  potential disruption due to:
    • node departures and failures
    • higher priority traffic
  • Traditional ALM is not sufficient
coopnet approach to robustness
CoopNet Approach to Robustness
  • Multiple description coding (MDC)
  • Multiple, diverse distribution trees
mu l tiple description coding
Multiple Description Coding

Layered coding

MDC

  • Unlike layered coding, there isn’t an ordering of the descriptions
  • Every subset of descriptions must be decodable
  • Modest penalty relative to layered coding
multiple description coding
Multiple Description Coding
  • Simple MDC:
    • every Mth frame forms a description
  • More sophisticated MDC combines:
    • layered coding
    • Reed-Solomon coding
    • priority encoded transmission
    • optimized bit allocation
tree management
Tree Management
  • Goals:
    • short and wide trees
    • efficiency
    • diversity
    • quick join and leave processing
    • scalability
  • CoopNet approach: centralized protocol anchored at the server
centralized tree management
Centralized Tree Management
  • Basic protocol
    • nodes inform server of their arrival/departure
    • server tracks node capacity and tells new nodes where to join
    • each node monitors its packet loss rate and takes action when the loss rate becomes too high
    • simple, should scale to 1000+ joins/leaves per sec.
  • Optimizations
    • delay coordinates to estimate node proximity (à la GeoPing)
    • achieving efficiency and diversity
    • migrate “stable” nodes to a higher level in the tree
mdc versus sdc
MDC versus SDC

Based on MSNBC traces from Sep 11

coopnet transport architecture
CoopNet Transport Architecture

Embedded Stream

ZSF

GOF

Parse

Packetize

Optimize

(M, p(m))

RD

Curve

Break Points

M descriptions

RS Encoder

Server

Internet

Depacketize

Embedded Stream(truncated)

Reformat

Decode

Render

GOF(quality depends on # descriptions received)

m≤ M descriptions

RS Decoder

Client

summary
Summary
  • Robustness is the key challenge
  • MDC with multiple distribution trees improves robustness in peer-to-peer media streaming
  • Centralized tree management is efficient and can scales
current activity
Current Activity
  • CoopNet media streaming system is being built
  • Evaluation:
    • adaptability
    • server scalability
    • media stream quality
    • overhead in MDC and control protocol
  • Dealing with client heterogeneity
    • combine MDC with layering
issues
Issues
  • Firewall and NAT traversal
  • Digital Right Management issues
  • ISP pricing policies
  • Enterprise scenarios
ad