Chapter 1

Prentice HallHigh Performance TCP/IP Networking, Hassan-Jain

Chapter 1

Introduction


Objectives

Understand the significance of TCP/IP in the modern era of pervasive computing and communication

Appreciate the need for designing and building high-performance TCP/IP networks

Gain a clear understanding of the metrics used for performance evaluation of TCP/IP networks


Contents

TCP History TCP Applications Significance of TCP Performance Performance Metrics


TCP History


Birth of TCP/IP

1973: First note by Dr. Vinton G. Cerf Only the concept of TCP (no separate IP)

1974: Cerf & Kahn published detailed discussion of TCP design in TranscomStill no separate IP

1974: First official spec. of TCP in RFC 675Still no separate IP

1978: Split into two protocol stacksTCP: RFC 760 IP: RFC 761


Adoption of TCP/IP

1980: DoD adopts TCP/IP as preferred protocol for ARPAnet

1983: All sites connected to ARPANet switch to TCP/IP


TCP

Applications


Basic TCP Applications

Email (SMTP) Web browsing (HTTP) File transfer (FTP) Remote login (RLOGIN)

These are the most popular, standard TCP applications. Other customized applications can be built on top of these basic applications.


Significance of

TCP Performance


Why Study TCP Performance

Dependence on TCP/IP networks The critical role of TCP protocol engine Emergence of new networking technologies

and environments IP convergence


Dependence on TCP/IP Networks

More people rely on TCP/IP networks than ever before

Some use TCP/IP consciously E.g. file download

Some use it without knowingFor example withdrawing money from ATM

machine


Dependence on TCP/IP (cont.)

We depend on TCP at office, home, and while on the move

We depend on TCP not only for research, but also for critical business transactions and entertainment

Internet (powered by TCP/IP) is now a key tool used by our kids to prepare their projects at schools


Critical Role of TCP

Many believe that network performance can be boosted by simply upgrading hardwareNot correct in many occasions

TCP sits between application and network TCP has total control of how application data

should be released to the network TCP is a complex protocol which interacts with

many network elements in the end to end path Unless TCP is optimized, hardware alone cannot

boost network performance


Emergence of New Networking Technologies

We are witnessing proliferation of different networking technologiesWireless, satellite, optical etc.

TCP algorithms suitable for one environment, do not always work best in another

Need for research into new algorithmsEvidence: large number of articles on TCP are

published every year in top journals and conferences


IP Convergence

Many traditional non-TCP/IP industries are converging to TCP/IPE.g. cellular communication, video and other

entertainments, etc.

Understanding TCP/IP performance fundamentals thus becomes important to scientists and engineers working in all these industries


Performance

Metrics


Performance Metrics

Round trip delay:The time needed to travel from source to destination, plus the time to travel from destination back to the source.

One way delay: The time needed to travel from source to destination, or from destination to source.

Maximum delay: Maximum tolerable delay


Performance Metrics (Cont.)

Delay variation (or jitter): Variation in delay for individual packets.

Packet loss rate: Ratio of the number of packets lost (or corrupted) to the total number of packets transmitted.

Bandwidth: Application bytes transferred in seconds.


Performance Metrics (Cont.)

Throughput variation: Variability in the received bandwidth over a given time scale.

File transfer time: Time takes to transfer a file/object on the WWW.

Fairness: Long-term/short-term fairness among all TCP/UDP flows.

Resource consumption: Amount of resource consumed, e.g. CPU cycles, memory usage, battery, etc.

Chapter 1

Documents

Transcript of Chapter 1