Computer Networking: A Top Down Approach �6^th edition �Jim Kurose, Keith Ross�Addison-Wesley�March 2012

Computer Communications �& Networks

CSNC-2413

• Introduction; Edge, Access, Core N/W

Lec: 1&2

Course Intro

• Basic course in Computer Networking
• Provides overview of…
• What are computer networks
• How do they operate
• How are they designed; (networks & applications)
• Adopts TOP DOWN approach…
• Types/needs of the distributed applications for N/Ws
• Various layered functionalities required for remote applications to communicate
• Relevant networking protocols/standards in wired/wireless domains

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Course Contents

• Computer Networks & the Internet
• Nuts & Bolts description
• Services description
• Network Edge & Core
• Delay, Loss & Throughput in packet switched networks
• Network architectures (TCP/IP, OSI)
• Application Layer
• Network applications, principles/architectures
• Services made available to Apps (by the N/W)
• Application layer protocols
• Web/HTTP, FTP, SMTP, POP3, DNS
• Apps development; Socket Programming (TCP & UDP)

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Course Contents

• Transport Layer
• Transport layer functions in Internet – Mux & de-Mux
• Connection less, unreliable transport – UDP
• Reliable Data Transfer (Go-Back-N, Selective Repeat ARQ)
• Connection oriented transport – TCP
• TCP Connection management, Flow control, Congestion Control
• Network Layer
• Network service model – Datagram & VC networks
• Forwarding & routing, What’s inside a router
• IPv4 protocol, Addressing, Subnetting, CIDR
• DHCP, NAT, ICMP, IPv6 protocol
• Routing algorithms – LS/DV routing

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4

Course Contents

• Link Layer
• Link layer functions
• Multiple access protocols
• Link layer addressing
• Link layer Technologies
• Ethernet - IEEE 802.3 standard

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Course Contents

• Network Programming :
• Socket Programming
• Client/Server communications paradigm
• TCP & UDP client-server comm
• Iterative & Concurrent servers
• Unix network programming in ‘C’
• Socket API

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Books Recommended

Text:

• Computer Networking: A Top-Down Approach (6^th Ed)
• by James F. Kurose & Keith W. Ross

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• Unix Network Programming – Vol I
• by W Richards Stevens

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Ref:

• Computer Networking: A Systems Approach (5^th Ed)
• by Larry L. Peterson & Bruce S. Davie

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Course Methodology

Lectures

• 30 power point lectures
• Study relevant sections of Text/Ref books

Assignments

• Assignment done in groups
• To be submitted exactly when due
• 5% marks deduction per day for being late
• After one week – Not Accepted

Exam Pattern

• Exams to include complete material in covered chapters
• MCQs, short answers, problems, design questions

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Grading Policy

Quizzes ………. 06 15%

Assignments ……… . 05 15%

Mid-exam ..….…. 25%

Final-exam .……… 40%

Class participation ………. 5%

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Distribution is tentative and flexible

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Academic Honesty

• Your work in this class must be your own
• If students are found to have:
• collaborated excessively, or
• copied/shared answers
• For the first infraction…
• all involved will, at a minimum, receive grades of 0
• Further infractions…
• will result in failure in course

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Attendance Policy

Strictly in accordance with the Univ policy…

Lets Start the Course…

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Chapter 1: Introduction

our goal:

• get “feel” and terminology
• more depth/detail later in course
• approach:
• use Internet as example

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overview:

• What is the Internet?
• What is a network protocol?
• Network Edge: hosts, access N/W, physical media
• Network Core: Internet structure, packet/circuit switching
• Performance: loss, delay, throughput
• Protocol layers, service models

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Chapter 1: roadmap

1.1 what is the Internet?

1.2 network edge

• end systems, access networks, links

1.3 network core

• packet switching, circuit switching, network structure

1.4 delay, loss, throughput in networks

1.5 protocol layers, service models

1.6 networks under attack: security

1.7 history

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What is the Internet: “Nuts & Bolts” view

• Computing devices:�(millions are connected)
• hosts & end systems
• run network apps
• generate data

• Communication links:
• copper, fiber, �radio, satellite
• have some bandwidth (data rate)

• Packet switches: �forward packets (chunks of data)
• switches & routers

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• What basic components make up the Internet…

• Internet: “network of networks”
• hierarchical structure
• interconnected ISPs

(lower tier ISPs, upper tier ISPs, …)

• home N/Ws plug into ISP N/Ws

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• Networking “protocols”
• run at end systems & switches
• control sending/receiving of msgs
• e.g, HTTP, Skype, TCP, IP, 802.11

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• Internet standards
• IETF: Internet Engineering Task Force
• RFC: Request for comments

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What’s the Internet: “Nuts & Bolts” view

“Fun” Internet appliances

IP picture frame

http://www.ceiva.com/

Web-enabled toaster +

weather forecaster

Internet phones

Internet

refrigerator

Slingbox: watch,

control cable TV remotely

Tweet-a-watt:

monitor energy use

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What’s the Internet: Services view

• What services are provided to Apps by Internet…
• Apps: Web, Email, VoIP, E-commerce, Internet TV/radio, audio/video on demand, video conf, online games, social nets
• Distributed Apps: involve multiple end systems that exchange data remotely
• Require different Types of Services: reliable or unreliable data delivery, thruput/delay needs, security
• How do Apps obtain services from network…???

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What’s the Internet: Services view

• End Systems provide an interface to apps
• Network API
• “Functions” that allow “process” on source end system to…
• “connect” to Internet
• “send/recv” data to app on dest end system
• Specifies syntax of how an appl� asks Internet to “deliver data”
• provides options for various types of services …

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• An important buzzword in computer networking… “Protocol“

“pre-defined set of rules”

• Analogy… Human protocol & Computer Network protocol…

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What’s a protocol?

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Network protocols?

• machines need coordination to interact with other machines
• require Network Protocols…

Network protocols define…

format/order of msgs sent/received among network entities,

& actions taken on msg Tx/Rx

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• all communication activity in Internet governed by protocols…
• specific msgs sent
• specific actions taken when msgs received, or other events

Network Structure

• network edge:
• end systems
• hosts & apps
• access networks
• N/Ws connecting end �systems to edge routers
• wired/wireless comm �links

• network core:
• interconnection of routers
• routes pkts from src to dst
• forms network of networks

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A

B

Network Analogy

A

Identify Network Equivalent components

Communication Link

Packets

End Systems

Packet Switches

The network edge

• End systems (hosts):
• host (run) appl programs
• e.g, Web, email

• Client/server model:
• hosts act as clients or servers
• server – always on powerful machine
• client – requests/receives service
• e.g, Web browser/server � Email client/server

• Peer-peer model:
• all hosts equal
• minimal (or no) use of dedicated servers
• e.g, Skype, BitTorrent, Gnutella

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Summary

1.1 what is the Internet?

1.2 network edge

• end systems, access networks, links

1.3 network core

• packet switching, circuit switching, network structure

1.4 delay, loss, throughput in networks

1.5 protocol layers, service models

1.6 networks under attack: security

1.7 history

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