Transcript Chapter 1

CSE 5346 – Networks II: High
Performance Networks
1
Introduction
Performance and
Quality of Service
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Course Foundation Assumptions
(pre-requisites)
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Good understanding of packet-switched
networking concepts and principles of
operation
Good understanding of Internet protocols
and architectures (e.g., IP protocol stack)
Solid foundation in computer operating
systems fundamentals
Ability to learn simple programming
languages (such as ns/2 tcl, C/C++)
Ability to perform independent research,
analyze findings and document results
Introduction
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What will we cover?
Some Review
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New Content
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Networking Introduction/Review
– Today… setting the stage
Frame Relay, ATM & High Speed LANs
Performance Modeling and Estimation
Congestion, Network Traffic
Analysis/Management and Routing
Quality of Service
Compression Standards and Practice
Advanced Topics (time permitting): VoIP,
Mobile IP, Mobile Agents
Introduction
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How will we cover it?
Classroom lectures
 Quizzes and exams
 Incremental modeling and simulation
project using ns/2
 Self-study research, and simulation
reports by students
 Study and student presentations on
relevant papers & RFCs
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Introduction
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Chapter 1 - Introduction
An Overview of Networking the Need for Speed and
Quality of Service
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Growth of the Internet
As of January 2005 …
> 300 million “computers”
in 209 countries
Introduction
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What is an/the Internet?
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connected computing
devices: hosts, endsystems
– PC’s, workstations,
servers
– PDA’s, phones,
toasters, cars
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running network
applications
communication links
– fiber, copper, radio,
satellite
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routers/switches:
forward packets
(chunks) of data thru
network
Introduction
router
server
local ISP
workstation
mobile
regional ISP
company
network
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The Need for Speed!
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Scale
– growing number of
hosts -> growing
demands on
bandwidth
– new technologies
result in new
paradigms for
device and
connection types
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e.g. ??
User Expectations!
Introduction
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Application
– demand for large
to huge file
transfers
– increasing critical
nature of Internet
use
– demand for “realtime” performance
characteristics
– demand for
guarantees of
service levels
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e.g. ??
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High-Speed Networks:
IDN to ATM
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IDN (Integrated Digital Network)
– early ’60s, answer to growth of digital,
computer-controlled, circuit-switched
networking
– WE 4ESS introduced in 1976, 1st large scale
commercial time-division switch
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ISDN (Integrated Services Digital
Network)
– integrated voice and data on the same digital
transmission links/exchanges
– small incremental cost for data over existing
digital voice network
Introduction
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High-Speed Networks:
IDN to ATM
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Frame Relay
– popularized standard (c. 1988) for
packet switching over ISDN
– most widely deployed WAN technology in
use today
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B-ISDN (Broadband ISDN)
– c. 1988: emerging demand for broadband
services
– new high-speed technologies available
– emerging bandwidth hungry applications
Introduction
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High-Speed Networks:
IDN to ATM
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ATM (Asynchronous Transfer Mode)
– early ’90s outgrowth of emerging need for highspeed switching over B-ISDN WAN
– rapidly evolved as high-speed packet switching
technology of its own accord
– primary deployment today is:
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public network infrastructure
LAN backbone
private network, VPN WAN
– services not widely deployed/available until
late-’90s.
Introduction
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High-Speed Networks:
ATM Backbone Example
Introduction
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High-Speed Networks: LANs
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High-speed LANs
– driven by explosive growth in speed and
computing power of PCs in 1990s
– emergence of client-server computing
architecture
– use of centralized server farms
– emergence of “power workgroups” and
workgroup applications
– need for local high-speed LAN
backbones
Introduction
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IP-based Internets (aka
TCP/IP networks)
Internetworking: the dominant
paradigm of computer networking
Evolution - key internetworking
technologies:
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packet switching
TCP/IP
– TCP: reliable end-to-end transport
– IP: internet routing and delivery
dynamic routing, load balancing
high speed Ethernet LANs
Introduction
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The Need for Improved
(better) Levels of Service
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Internet BestEffort Service
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Applications
– often create
inelastic traffic
– often sensitive to
delay
– often sensitive to
jitter
– often critical in
nature
– generate elastic
traffic as well
– all packets treated
equally
– designed for
elastic traffic
– no guarantees of
bandwidth or
throughput
– no guarantees of
delay
– no guarantee of
jitter (delay
 User Requirements!
variation)
Introduction
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Delay Sensitivity & Criticality
Introduction
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Delays in Packet Switched
(e.g. IP) Networks
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End-to-end delay (simplified) =
(dprop + dtrans + dqueue + dproc) x Q
A
B
Where:
 Propagation delay (dprop)
 Transmission delay (dtrans)
 Queuing delay (dqueue)
 Processing delay (dproc)
 Number of links (Q)
Introduction
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So what’s the problem?
What makes this so hard?
(I.e., what are we going to focus on
in this course.)
Introduction
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Delays in Packet Switched
(e.g. IP) Networks
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A
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End-to-end delay (simplified) =
– (dprop + dtrans + dqueue + dproc) … on each link
Where:
B
 Propagation delay (dprop) = d/s
 Transmission delay (dtrans) = L/R
 Queuing delay (dqueue) = ?
 Processing delay (dproc) = ?
More later
 Number of links (Q) = ?
Introduction
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