lyu9903 qos schemes in wireless networks
DESCRIPTION
LYU9903 QoS Schemes in Wireless Networks. Ho Pun Mo & Ng Maggie Supervised by Prof. Lyu R.T. Michael 6 December, 1999. Outline. Introduction Wireless Networks QoS Performance Evaluation QoS in Wireless Networks Application - Video Future Work. Introduction. - PowerPoint PPT PresentationTRANSCRIPT
LYU9903LYU9903QoS Schemes in Wireless QoS Schemes in Wireless
NetworksNetworksHo Pun Mo & Ng MaggieHo Pun Mo & Ng Maggie
Supervised by Prof. Lyu R.T. Michael
6 December, 1999
Outline
• Introduction
• Wireless Networks
• QoS
• Performance Evaluation
• QoS in Wireless Networks
• Application - Video
• Future Work
IntroductionIntroduction
• Concern about QoS and wireless networks
• QoS is not as simple as one would think
• Platform we choose is Linux
• Focus on: investigating and analyzing QoS schemes on wireless networks measuring and comparing performance on wired/wireless networks
Wireless NetworksWireless Networks
• Wireless Local Area Networks (Wireless LANs)
• Wireless Wide Area Networks (Wireless WANs)
Wireless LANsWireless LANs
• Extension to /Alternative for Wired Network
• IEEE 802.11 standard
• Using Radio Frequency (RF)
• connected as infrastructure network
Wired vs Wireless Wired vs Wireless NetworksNetworks
• different physical & datalink protocols
• different hardware
• wireless networks: Roaming
• different performance
Why Wireless?Why Wireless?
• Importance of Wireless LANs:increasing of mobility
• Trend of Wireless LANs:better performancelower cost
Why Wireless?Why Wireless?
• Applications of Wireless LANs:in hospitalsin campusin retail stores & restaurantsin warehousesin old buildings
Wireless DevicesWireless Devices
• Access Points:
Proxim RangeLAN2 Ethernet & Token Ring Access Point
WaveLAN WavePOINT-II Access Point
Wireless DevicesWireless Devices
• PC Cards:
WaveLAN Turbo(Bronze) PC Card Proxim RangeLAN2 7400 PC Card
• Date Rate: 2-6 Mbps
• Range: 40-115m (indoor) 120-540m (outdoor)
• Freq.: 2400-2483.5MHz
• Date Rate: 1.6 Mbps
• Range: 152m (indoor) 305m (outdoor)
•Freq.: 2.4GHz
Pros & Cons of WirelessPros & Cons of Wireless
• Advantages:MobilityFlexibilityEase of InstallationCost of InstallationSecurityEnough Bandwidth for Office Uses
Pros & Cons of WirelessPros & Cons of Wireless
• Disadvantages:Low BandwidthHigh Error Rates & High DelayLimited Range of CoverageLarge Consumption of BatteryUnwanted Interference
What is QoS?What is QoS?
• There are many QoS’s
• We concern about QoS in computer networks
• Some definitions: the collective effect of service performances which determine the degree of
satisfaction of a user of the service
the ability of a network to deliver time-bounded traffic types (e.g. real time video or voice) with predictable latencies
a way to specify an applications network performance requirements, and it is specified by performance parameters
What is QoS?What is QoS?
• What QoS means to us:
QoS is the guarantee of delivering network packets QoS is the guarantee of delivering network packets punctually and the guarantee of delivering an acceptable punctually and the guarantee of delivering an acceptable numbers of network packets in a compromised time numbers of network packets in a compromised time interval, which would not annoy the receivers.interval, which would not annoy the receivers.
Why QoS?Why QoS?
• Statistic from Cisco shows that multimedia applications become more and more popular
How to Achieve QoS?How to Achieve QoS?
• Many ways
Bandwidth reservation + Packet scheduling
• Bandwidth reservationRSVP
• Packet schedulingCBQ
How to Achieve QoS?How to Achieve QoS? ~ Bandwidth ~ Bandwidth ReservationReservation
• RSVPRSVP is a protocol that allows channels or paths on the networks to be reserved for the transmission of video and other high-bandwidth messages.
How to Achieve QoS?How to Achieve QoS? ~ Packet ~ Packet
SchedulingScheduling• There are many packet scheduling algorithms
• Some examples: FIFO - First In First Out SFQ - Stochastic Fairness Queuing WFQ - Weighted Fair Queuing CBQ - Class Based Queuing
• Focus on CBQ
Performance EvaluationPerformance Evaluation~ Wired ~ Wired
NetworksNetworks• Scenario:
Server Client
Ethernet
Application:FTP
Application:MP3 player
Performance EvaluationPerformance Evaluation~ Wired ~ Wired
NetworksNetworks• Results with & without QoS
Received Bandwidth of FTP & MP3using QoS with 200Kbit
0
50
100
150
200
250
300
350
400
0 50 100 150 200 250 300 350Time (sec)
Cur
rent
Ban
dwid
th (K
bps)
FTP
MP3
Received Bandwidth of FTP & MP3with NO QoS, with 200Kbit
0
50
100
150
200
250
300
350
400
0 100 200 300 400 500
Time (ms)
Cur
rent
Ban
dwid
th (
Kbp
s)
FTP
MP3
Performance EvaluationPerformance Evaluation~ Wired ~ Wired
NetworksNetworks• Applied QoS & NoQoS in same experiment
Received Bandwidth of FTP & MP3using NO QoS at first 2min and
using QoS after 2min with 200Kbit
0
50
100
150
200
250
300
350
400
0 100 200 300 400Time (sec)
Cur
rent
Ban
dwid
th (
Kbp
s)
FTP
MP3
noqos qos
Performance EvaluationPerformance Evaluation~ Wired ~ Wired
NetworksNetworks• What can you see from the results?
QoS makes MP3 playing smoothly
QoS benefits both MP3 and FTP applications
QoS can be applied on the fly
Performance EvaluationPerformance Evaluation~ Wireless ~ Wireless
NetworksNetworks• Scenario:
Server
Client
Ethernet
Application:FTP
Application:MP3 player
Access Point
Performance EvaluationPerformance Evaluation~ Wireless ~ Wireless
NetworksNetworks• Performance on using the Proxim devices
Received Bandwidth of FTP & MP3 using QoS with200Kbits (using Proxim)
0
50
100
150
200
250
300
0 100 200 300 400 500
Time (sec)
Cur
rent
Ban
dwid
th (K
bps)
FTPMP3
Received Bandwidth of FTP & MP3 without QoSwith 200Kbits (using Proxim)
0
50
100
150
200
250
0 100 200 300 400 500 600
Time (sec)
Cur
rent
Ban
dwid
th (
Kbp
s)
FTP
MP3
Performance EvaluationPerformance Evaluation~ Wireless ~ Wireless
NetworksNetworks• Performance on using the WaveLAN devices
Received Bandwidth of FTP & MP3 using QoSwith 200Kbits (using WaveLAN)
0
50
100
150
200
250
300
0 100 200 300 400 500Time (sec)
Cur
rent
Ban
dwid
th (K
bps)
FTPMP3
Received Bandwidth of FTP & MP3 without QoSwith 200Kbits (using waveLAN)
0
50
100
150
200
250
300
0 100 200 300 400 500 600
Time (sec)
Cur
rent
Ban
dwid
th (K
bps)
FTPMP3
Performance EvaluationPerformance Evaluation~ Wireless ~ Wireless
NetworksNetworks• With / without QoS in the same experiment
Received Bandwidth of FTP & MP3 with 200Kbits (using Proxim)
Received Bandwidth of FTP & MP3 with 200Kbits (using WaveLAN)
noqosnoqos
qosqos
Performance EvaluationPerformance Evaluation~ Wireless ~ Wireless
NetworksNetworks• What can you see from the results?
QoS makes MP3 playing smoothlyQoS benefits both MP3 and FTP applicationsWired Networks vs Wireless Networks:
Wireless Networks have larger delayProxim vs WaveLAN:
seems Proxim performs better!
QoS in Wireless QoS in Wireless NetworksNetworks
• Problems: Variable bandwidth Roaming Low Reliability and Long Delay Interference Hard disk bottleneck
• Solutions: Renegotiation Apply QoS in Access Points Network Collision Control
Application - VideoApplication - Video
• Real time video player for both wired and wireless networks with QoS enabled
• Design:RPCEnabled QoS
Buffering at both client and server side RAPI
Future WorkFuture Work
• Measure the delay jitter of the QoS systems (both wired and wireless)
• Measure the performance of the QoS systems with router presented
• Finish our video application with QoS enabled• Measure the performance of our video application • Inspect the source code of WaveLAN driver in order to
make it QoS enabled