Differentiated Services Over UMTS

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Differentiated Services Over UMTS
Math 884 Presentation
Presented By

• Nidal Nasser

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Presentation Outline

• QoS Definition
• DiffServ Overview
• UMTS Overview
• DiffServ Over UMTS
• Current Work
• Case Study

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Quality of Services

• Definition
• Ability of a network element (e.g. application,
  host or router) to have some level of assurance
  that its traffic and service requirements can be
  satisfied
• Main QoS Parameters
• Delay
• Delay variations (jitter)
• Throughput
• Packet loss rate

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The DiffServ Model

• DiffServ
• allowing network service providers to offer
  different levels of Quality of Service (QoS) to
  different traffic streams
• Design goals
• Keep the forwarding path simple
• Push complexity to the edges
• Avoid assumptions about traffic type

Diffserv Domain
SLA
Sender
Egress
Receiver
Ingress
Core
SLA Service Level Agreement
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The DiffServ Model
SLA

• Ingress routers
• Police/shape traffic
• Set Differentiated Service Code Point (DSCP) in
  Diffserv (DS) field

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Differentiated Service (DS) Field
0
5
6
7
DS Filed
0
4
8
16
19
31
Version
HLen
TOS
Length
Identification
Flags
Fragment offset
IP header
TTL
Protocol
Header checksum
Source address
Destination address
Data

• DS filed reuse the first 6 bits from the former
  Type of Service (TOS) byte
• The other two bits are reserved for future use

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Differentiated Services

• Current PHBs defined for DiffServ to implement
  QoS
• Premium Forwarding (PF)
• Assured Forwarding (AF)
• Best-Effort (BE)
• The type of traffic currently supported by the
  Internet with no guarantees or QoS

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Premium Forwarding (PF)

• Provides the abstraction of a virtual pipe
  between an ingress and an egress router
• Network
• guarantees that premium packets are not dropped
  and they experience low delay
• User
• does not send more than the size of the pipe
• If it sends more, excess traffic is delayed, and
  dropped when buffer overflows
• low delay low loss low jitter guaranteed BW

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Assured Forwarding (AF)

• Defined in terms of user profile, how much
  assured traffic is a user allowed to inject into
  the network
• 4 classes with each 3 different levels of drop
  priority
• Network
• provides a lower loss rate than best-effort
• In case of congestion best-effort packets are
  dropped first
• User
• sends no more assured traffic than its profile
• If it sends more, the excess traffic is converted
  to best-effort
• Low loss, target BW rate, but no guarantee on
  delay

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UMTS Overview

• UMTS Universal Mobile Telecommunication System
• International Telecommunication Union (ITU)
  defines the set of requirements of the 3G
  IMT-2000
• Used worldwide
• Used for all mobile applications (e.g. streaming
  video)
• Support both packet-switched (PS) and
  circuit-switched (CS) data transmission
• Offer high data rates up to 2 Mbps
• Offer high spectrum efficiency

• Spectrum for UMTS
• 1920 MHz - 1980 MHz FDD Uplink 
• 2110 MHz - 2170 MHz FDD Downlink
• 1900 MHz - 1920 MHz TDD 2010 MHz - 2025 MHz
• 1980 MHz - 2010 MHz MSS (Mobile Satellite
  Service) Uplink
• 2170 MHz - 2200 MHz MSS Downlink

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UMTS Cell Structure
Building, 2 Mbps
City, 188 kbps
Campus, 384 kbps
Satellite area, ???
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UMTS Network Architecture
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UMTS QoS Architecture

• QoS is defined by ITU as the collective effect of
  service performance which determines the degree
  of satisfaction of a user of the service

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UMTS QoS Classes (Traffic Classes)
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UMTS QoS Classes Parameters
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Wireless Environment Problems

• Radio link
• Higher bit error rates
• Multipath propagation phenomena
• Reflection Diffraction Scattering
• gt The received signal power is affected
  randomly by each or combination of these
  mechanisms
• Interference
• Many users use a common share bandwidth at the
  same time
• Spectrum Limitation
• Mobility

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A QoS Model for DiffServ over UMTS
Q. Is it possible to apply the DiffServ model
over UMTS environment?

• Ans.
• How to map between the UMTS classes onto DiffServ
  classes?
• No standard
• Where is the DiffServ in the CN of UMTS?
• Where is the DiffServ in the RAN of UMTS?
• Air Interface Wideband CDMA (WCDMA)

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UMTS to DiffServ

• A proposal for mapping UMTS classes onto DiffServ
  classes

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DiffServ in the CN of UMTS
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DiffServ in the RAN of UMTS

• Resource management (Uplink and Downlink)
• Admission Control
• Congestion Control
• Flow Control
• Power Assignment

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Case StudyPacket Priority Scheduling Algorithms
in UMTS Downlink

• Scheduling enhances system capacity by
  dynamically sharing the same resources among
  different classes of users
• The goal providing the required QoS guarantee to
  different classes of users

MS 2
MS 3
MS 4
MS N
MS1
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Packet Priority Scheduling Algorithms

• Two types of traffic classes
• Real-time, voice the highest priority
• Non-real-time, data packets the lowest priority
• Within each class FIFO
• Scheduling Algorithms
• Least Served Priority Scheduling
• Best Quality Scheduling
• Earliest Deadline Priority Scheduling

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Simulation Results
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Simulation Results
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DiffServ over UMTS
For more information Nidal Nasser nasser_at_cs.queens
u.ca Goodwin Hall, 623 or 627