230 likes | 462 Views
Introduction. 1-2. Introduction. Overview of the courseBasic concepts and structures in computer networkingNetwork architecture. Introduction. 1-3. Computer Networks. A computer network is a system for communication among two or more computersWhat amounts to
E N D
1. Introduction 1-1 COSC6377: Computer Networks Rong Zheng
rzheng@cs.uh.edu
2. Introduction 1-2 Introduction Overview of the course
Basic concepts and structures in computer networking
Network architecture
3. Introduction 1-3 Computer Networks A computer network is a system for communication among two or more computers
What amounts to “computers”?
What kind of communication? – “digital”
System: both software & hardware
Examples?
4. Introduction 1-4 History of the Internet 61-72: development of packet switching
72-80: Proprietary networks and internetworking
Multiple packet switching networks
“Networks of networks”: earlier development of TCP, UDP, IP
ALOHA, Ethernet
80-90: proliferation of networks
Standardization of networking protocols TCP/IP, DNS etc
NSF builds NSFNET as backbone, links 6 Supercomputer centers, 1.5 Mbps, 10,000 computers
90’s: Internet explosion
94: NSF backbone dismantled, multiple private backbones
Emergence of World Wide Web (invented by Time Berners-Lee) Chap 1.3Chap 1.3
5. Introduction 1-5 Internet “Hall of Fame” Al Gore, former vice president of USA
Vinton G. Cerf and Robert E. Kahn
2004 Turing Award winner “For pioneering work on internetworking, including the design and implementation of the Internet's basic communications protocols, TCP/IP, and for inspired leadership in networking”
Turing lecture: http://www.acm.org/sigs/sigcomm/sigcomm2005/webcast.html
David Clark et al “end2end arguments”
Van Jacobson, TCP congestion control
Robert Metcalfe, inventor of Ethernet
…
6. Introduction 1-6 Growth of the Internet Number of Hosts on the Internet:
Aug. 1981 213
Oct. 1984 1,024
Dec. 1987 28,174
Oct. 1990 313,000
Oct. 1993 2,056,000
Apr. 1995 5,706,000
Jan. 1997 16,146,000
Jan. 1999 56,218,000
Jan. 2001 109,374,000
Jan 2003 171,638,297
7. Introduction 1-7 Growth of the Internet Traffic on Internet (in TB/mo)
1990 1.0
1991 2.0
1992 4.4
1993 8.3
1994 16.3
1996 1,500
1997 2,500 - 4,000
1998 5,000 - 8,000
1999 10,000 - 16,000
2000 20,000 - 35,000
2001 40,000 - 70,000
2002 80,000 - 140,000
8. Introduction 1-8 Growth of the Internet Internet bandwidth
Nielsen’s law: 50% each year What do you gather from the data?What do you gather from the data?
9. Introduction 1-9
10. Introduction 1-10 What is Next Big Thing? I wish I have the answer
Technology
Wireless broadband networks
Optical switching networks (?)
Application
VOIP
Peer-to-peer applications
Online gaming
Sony’s EverQuest servers host 600,000 PC gamers
11. Introduction 1-11 A Few Words on Networking Research Wireless System Research Group (WiSeR)
http://coco.cs.uh.edu/~rzheng
12. Introduction 1-12 What will be covered? Network architecture, services, apps
TCP/IP
Protocol details
Algorithms
Performance analysis
Ethernet, Wireless networks
Multimedia networks
QoS scheduling
Signaling
Network security
Basic knowledge
Attacks and counter-measures
Network management
13. Introduction 1-13 What will not be covered? Socket programming (chap 2.7-2.9)
Physical layer technologies (chap 1.4)
Cellular networks
Multicast routing (chap 4.7)
ATM, frame relay, PPP (chap 5.7-5.8)
The emphasis is no only on “how” but also “why”
Knowledge base
Reasoning behind the design
14. Introduction 1-14 Logistics Textbook, reference book
Office hour
Homework, project policy
Grade
Prerequisite test:
What are the OSI-ISO layers? How is it related to the practice in the Internet?
What is protocol?
What is the difference between packet switching and circuit switching?
Sockets
15. Introduction 1-15 Introduction Overview of the course
Basic concepts and structures in computer networking
Network architecture
16. Introduction 1-16 What’s the Internet: “nuts and bolts” view End systems
Host computer
Network applications
Access networks
Local area networks
communication links
Network core:
routers
network of networks
17. Introduction 1-17 What’s the Internet: “nuts and bolts” view Protocols control sending, receiving of msgs
e.g., TCP, IP, HTTP, FTP, PPP
Internet: “network of networks”
loosely hierarchical
public Internet versus private intranet
Internet standards
RFC: Request for comments
IETF: Internet Engineering Task Force
18. Introduction 1-18 Network Components (Examples)
19. Introduction 1-19 Juniper Routers
20. Introduction 1-20 Internet structure: network of networks roughly hierarchical
at center: “tier-1” ISPs (e.g., MCI, Sprint, AT&T, Cable and Wireless), national/international coverage
treat each other as equals
21. Introduction 1-21 Tier-1 ISP: e.g., Sprint
22. Introduction 1-22 Internet structure: network of networks “Tier-2” ISPs: smaller (often regional) ISPs
Connect to one or more tier-1 ISPs, possibly other tier-2 ISPs
23. Introduction 1-23 Internet structure: network of networks “Tier-3” ISPs and local ISPs
last hop (“access”) network (closest to end systems)
24. Introduction 1-24 Internet structure: network of networks a packet passes through many networks!