Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

Exploring Computer Networks: Protocols, Layers, and Internet Architecture, Slides of Computer Networks

An introduction to computer networks, explaining why they are worth studying, the goals of the class, and the process of network trace analysis. It covers various topics such as dns traffic, tcp connection establishment, http request/response, and ip datagrams. Students will gain practical skills in network analysis and programming, and learn about the history and growth of the internet.

Typology: Slides

2012/2013

Uploaded on 04/25/2013

avantika
avantika 🇮🇳

4.3

(22)

157 documents

1 / 53

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
-1
1:
Introduction
Docsity.com
pf3
pf4
pf5
pf8
pf9
pfa
pfd
pfe
pff
pf12
pf13
pf14
pf15
pf16
pf17
pf18
pf19
pf1a
pf1b
pf1c
pf1d
pf1e
pf1f
pf20
pf21
pf22
pf23
pf24
pf25
pf26
pf27
pf28
pf29
pf2a
pf2b
pf2c
pf2d
pf2e
pf2f
pf30
pf31
pf32
pf33
pf34
pf35

Partial preview of the text

Download Exploring Computer Networks: Protocols, Layers, and Internet Architecture and more Slides Computer Networks in PDF only on Docsity!

Introduction

Why study computer networks?

 They are engineering marvels!

 Scalability, layered protocols, lots of

subtleties- worthy of study

 They are all around us!

 Understanding the nuts and bolts behind a

technology you use every day is exciting

 They are changing the world!

 Profound societal changes taking place in our

lifetime

Goals of this class

 Understand both basic computer

networking concepts and their instantiation

in the current Internet

 Question why the current Internet is the

way it is

 Appreciate good

 Understand limitations and consider solutions

 Gain practical skills (network analysis,

network programming)

Network Trace Analysis?

 Network Trace Analysis - what happens on

our local network when use a network

application?

Example: Web browsing

 Trace a common network operation like web browsing

 URL like http://www.google.com specifies

  • protocol (http)
  • location (www.google.com)

 What network traffic results?  Request page  Send page  What else? Lots….

DNS traffic

 www.google.com is the

name of a computer

(and, implicitly, of a

file in that computer)

 To find the address,

the application uses a

hierarchical directory

service called the

Domain Name System to translate human readable names to IP addresses

local

com

host

www.google..com?

www.google.com? (^) IP = a.b.c.d

IP = a.b.c.d

TCP Connection Establishment

 The protocol (http) sets up a connection (another

protocol, tcp) between the host and

www.google.com to transfer the page

 SYN, SYNACK, ACK

Host www.google.com

connect

OK get page page; close

HTTP request/response

 GET /foo.html HTTP/1.

 Server responds sending page

2: Application Layer 13

QUICK LOOK AHEAD: TCP vs UDP

TCP service:

 connection-oriented: setup

required between client, server

 reliable transport between

sending and receiving process

 flow control: sender won’t

overwhelm receiver

 congestion control: throttle

sender when nework overloaded

 does not providing: timing,

minimum bandwidth guarantees

UDP service:

 unreliable data transfer between sending and receiving process  does not provide: connection setup, reliability, flow control, congestion control, timing, or bandwidth guarantee

IP Datagrams

 Datagrams labeled with where they are

going and where they are from – no

directions

 Source IP address

 Destination IP address

Path through the Internet

 Network trace analysis very useful but it gave us

very little hint that between our machine and the

remote machine there are many hops

Traceroute/tracert

How are paths established?

 Packets flows from end to end across many links

 Routers receive packet and try to forward one step closer to destination ( routing )

 The packets contain all information necessary to indicate destination (addressing) and are handled individually  Example: Caravan of cars on a road trip

 Packets may take different paths

C

HOST: B

GOOGLE. COM: A A | B | # , CRC | bytes

B: to C

Internet Topology?

 Traceroute gave us one slice through the Internet

 What does that tell us about the routes in the

entire Internet? The full Internet map?