Xin Wang

1
Resource Negotiation, Pricing and QoS
for Adaptive Multimedia Applications

• Xin Wang
• With Henning Schulzrinne
• Internet Real -Time Laboratory
• Columbia University
• http//www.cs.columbia
  .edu/xinwang/RNAP.html

2
Todays IP Networks
Service Level Agreements (SLA) are negotiated
based on Application Specific Needs bandwidth,
loss, delay, jitter, availability, price
ISP Networks
Applications
IP Network
Service
User
SCOPE

• Growth of new IP services and applications with
  different bandwidth and quality of service
  requirements
• Presents opportunities and challenges for service
  providers

3
The needs of Next Generation Service
Providers

• Revenue from the traditional connectivity
  services (raw bandwidth) is declining
• Increase revenue by offering innovative IP
  services
• Deliever high-margin, differentiated services
• VoIP, VPN, Applications Hosting etc
• Gain competitive advantage by deploying new
  services more quickly, placing a premium on time
  to market and time to scale
• Reduce cost and operation complexity
• Evolve from static network management to dynamic
  service provisioning
• Reduce costs by automating network and service
  management

4
Internet Structure
5
NORDUnet Traffic Analysis
6
NORDUnet Traffic Analysis

• Results
• All access links (interconnect ISPs or connect
  private networks to ISPs), including
  trans-Atlantic links, can get congested.
• Average utilization is low 20-30
• Peak utilization can be high up to 100
• Congestion Ratio (peak/average) as high as 5.
• Peak duration can be very long
• Chicago NAP congested once in 8/00, lasted 7
  hours.
• TeleGlobe links congested every workday in 8/00
  and 9/00
• Reasons Frequent re-configuration and
  upgradingLoad balancing to protect own users.

7
Solution - Over-provisioning?

• Add enough bandwidth for all applications in
  access network / backbone
• Will over-provisioning be sufficient to avoid
  congestion?
• How much bandwidth is enough to meet diverse user
  requirements?
• No intrinsic upper limit on bandwidth use
• How much does it cost to add capacity?

8
Bandwidth Pricing

• Reality leased bandwidth price has not been
  dropping consistently and dramatically.
• Facts
• 300 mile T1 price (rent)
• 1987 10,000/month
• 1992 4,000/month
• 1998 6,000/month (thanks to high Internet
  demand)
• 100-mile cabling cost in 1998 65,000
• Links connecting ISPs are very expensive

9
Bandwidth Pricing (cont.)

• Facts
• International Frame Relay with 256-kbps
  thousands dollars a month.
• Transit DS-3 link 50,000/month between
  carriers.
• Transit OC-3 link 150,000/month between
  carriers.
• Chicago NAP
• 3,900/month/DS-3,
• 4,700/month/OC-3.

Bandwidth may be cheap, but not free Higher-speed
connection -- higher recurring monthly
costs. Option - manage the existing bandwidth
better, with a service model which uses bandwidth
efficiently.
10
Solution - Other Service Models

• Quality of Service (QoS)
• Condition the network to provide predictability
  to an application even during high user demand
• Provide multiple levels of QoS to meet diverse
  user requirements
• How efficient a QoS mechanism manages the
  bandwidth? How much a user needs to pay for QoS?
• Application adaptation
• Source rate adaptation based on network
  conditions can avoid congestion and lead to
  efficient bandwidth utilization
• Why would an application adapt?

11
A more Efficient Service Model

• Dynamic resource negotiation
• Network commits resources for short intervals -
  better response to changes in network conditions
  and user demand
• Usage-,QoS-,demand-sensitive pricing
• Allow network to price services based on
  resources consumed, and allocate resources
  based on user willingness-to-pay
• Give user incentive to select appropriate service
  based on requirements, adapt demand during
  network resource scarce in response to price
  increase

12
What We Add to Enable This Model?

• A dynamic resource negotiation protocol RNAP
• An abstract Resource Negotiation And Pricing
  protocol
• Enables user and network (or two network domains)
  to dynamically negotiate multiple services with
  different QoS characteristics
• Enables network to formulate and communicate
  prices and charges
• Lightweight and flexible embedded in other
  protocols, e.g., RSVP, or implemented
  independently
• Ensures service predictabilitycommit service and
  price for an interval
• Supports multi-party negotiation senders,
  receivers, or both
• Reliable and scalable
• A demand-sensitive pricing model
• Enables differential charging for supporting
  multiple levels of services services priced to
  reflect the cost and long-term user demand
• Allows for congestion pricing to motivate user
  adaptation

13
What we add... (contd)

• Demonstrate a complete resource negotiation
  framework (RNAP, pricing model, user adaptation)
  on test-bed network
• Simulations show significant advantages relative
  to static resource allocation and fixed pricing
• Much lower service blocking rate under resource
  contention
• Service assurances under large or bursty offered
  loads, without high provision complexity, or
  over-provision cost
• Higher perceived user benefit and higher network
  revenue