Post on 19-Dec-2015
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EECS 122: Introduction to Computer Networks
Course Goals and Overview
Computer Science Division
Department of Electrical Engineering and Computer Sciences
University of California, Berkeley
Berkeley, CA 94720-1776
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Instructors
Instructors- Randy Katz (randy@cs.Berkeley.edu), Office Hours: Tu 1-2 PM, W
11-12 noon, and by appointment, 637 Soda Hall
- Ion Stoica (istoica@cs.Berkeley.edu), Office Hours: M 5-6 PM, W 4-5 PM, 645 Soda Hall
Textbooks- L. L. Peterson and B. Davie, Computer Networks: A System
Approach, 3nd Edition, Morgan Kaufman, San Francisco, 2003.
- W. R. Stevens, B. Fenner, A. M. Rudoff, Unix Network Programming: The Sockets Networking API, Vol. 1, 3rd Ed., Addison-Wesley, Boston, 2004.
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TAs
Byung-Gon Chun, bgchun@cs.Berkeley.eduTu 4-5 PM, room TBD
Xuanming Dong, xuanming@eecs.Berkeley.edu Time and room TBD
Ling Huang, hling@cs.Berkeley.eduTu 2-3 PM, room TBD
Sonesh Surana, sonesh@cs.Berkeley.eduTime and room TBD
For final office hour schedule, please see the web
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Administrivia
Course Web page: - http://inst.eecs.berkeley.edu/~ee122/- Check often to get the latest information
Deadlines- HWs: due 10:50 am on the indicated date (10 minutes
before lecture) Exams are closed-book, with open crib sheet Come to office hours, request an appointment,
communicate by e-mail- We are here to help, including general advice!- TAs first line for help with programming problems
Give us suggestions/complaints as early as possible
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Course Goals
Learn the main architectural concepts and technological components of communication networks, with the Internet as the overarching example
- Understand how the Internet works
- And why the Internet is the way it is
Apply what you learned in three mini-class projects
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Class Workload
NOTE: EE122 is a 4 unit course starting this semester! Four homeworks spread over the semester
- Strict deadlines and due dates (no slip days!) Three (mini-)projects
- 1st and 3rd are part of a larger project, which involves implementing a comprehensive network application
• C (or C++) required
- 2nd is a simulation project Two midterm exams
- September 30 and November 4 Final exam
- December 16
- Note dates and plan your travel accordingly!
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Grading
Consultation on HWs is OK, but must hand in own work- Correlation between understanding HWs and doing well on exams
Course graded to mean of B- Relatively easy to get a B, harder to get an A or a C- 10% A, 15% A-, 15% B+, 20% B, 15% B-, 15% C+, 10% C- A+ reserved for superstars (only 1 or 2 per class)- Mean can shift up for an especially great class
Homeworks 20%
(5% each)
Projects 40%
(10% + 10% + 20%)
Midterm exams 20%
(10% each)
Final exam 20%
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Overview
Administrivia Overview and History of the Internet
• See http://www.isoc.org/internet/history/ for more details
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What is a Communication Network?(End-system Centric View)
Network offers one basic service: move information- Bird, fire, messenger, truck, telegraph, telephone, Internet …- Another example, transportation service: move objects
• Horse, train, truck, airplane ... What distinguish different types of networks?
- The services they provide What distinguish the services?
- Latency- Bandwidth- Loss rate- Number of end systems- Service interface (how to invoke the service?)- Others
• Reliability, unicast vs. multicast, real-time...
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What is a Communication Network?(Infrastructure Centric View)
Communication medium: electron, photon Network components:
- Links – carry bits from one place to another (or maybe multiple places): fiber, copper, satellite, …
- Interfaces – attach devices to links
- Switches/routers – interconnect links: electronic/optic, crossbar/Banyan
- Hosts – communication endpoints: workstations, PDAs, cell phones, toasters
Protocols – rules governing communication between nodes- TCP/IP, ATM, MPLS, SONET, Ethernet, X.25
Applications: Web browser, X Windows, FTP, ...
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Network Components (Examples)
Fibers
Coaxial Cable
Links Interfaces Switches/routers
Ethernet card
Wireless card
Large router
Telephoneswitch
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Types of Networks
Geographical distance- Local Area Networks (LAN): Ethernet, Token ring, FDDI- Metropolitan Area Networks (MAN): DQDB, SMDS- Wide Area Networks (WAN): X.25, ATM, frame relay- Caveat: LAN, MAN, WAN may mean different things
• Service, network technology, networks Information type
- Data networks vs. telecommunication networks Application type
- Special purpose networks: airline reservation network, banking network, credit card network, telephony
- General purpose network: Internet
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Types of Networks
Right to use- Private: enterprise networks- Public: telephony network, Internet
Ownership of protocols- Proprietary: SNA- Open: IP
Technologies- Terrestrial vs. satellite- Wired vs. wireless
Protocols- IP, AppleTalk, SNA
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The Internet (cont’d)
Global scale, general purpose, heterogeneous-technologies, public, computer network
Internet Protocol- Open standard: Internet Engineering Task Force (IETF) as
standard body ( http://www.ietf.org )
- Technical basis for other types of networks
• Intranet: enterprise IP network
Developed by the research community
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Internet vs. Telephone Net
Strengths
- Intelligence at ends
- Decentralized control
- Operates over heterogeneous access technologies
Weaknesses
- No differential service
- Variable performance delay
- New functions difficult to add since end nodes must be upgraded
- No trusted infrastructure
Strengths
- No end-point intelligence
- Heterogeneous devices
- Excellent voice performance Weaknesses
- Achieves performance by overallocating resources
- Difficult to add new services to “Intelligent Network” due to complex call model
- Expensive approach for reliability
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History of the Internet
68-70’s: started as a research project, 56 kbps, initially 4 nodes (UCLA, UCSB, SRI, Utah) then < 100 computers
- 2 September 2004/35th Anniversary of the Internet- http://www.cnn.com/2004/TECH/internet/08/29/internet.birthda
y.ap/index.html
80-83: TCP/IP, DNS; ARPANET and MILNET split 85-86: NSF builds NSFNET as backbone, links 6
Supercomputer centers, 1.5 Mbps, 10,000 computers 87-90: link regional networks, NSI (NASA), ESNet (DOE),
DARTnet, TWBNet (DARPA), 100,000 computers 90-92: NSFNET moves to 45 Mbps, 16 mid-level networks 94: NSF backbone dismantled, multiple private backbones;
Introduction of Commercial Internet Today: backbones run at 10 Gbps, close to 200 millions
computers in 150 countries
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The ARPANet
Paul Baran
- RAND Corp, early 1960s
- Communications networks that would survive a major enemy attack
ARPANet: Research vehicle for “Resource Sharing Computer Networks”
- 2 September 1969: UCLA first node on the ARPANet
- December 1969: 4 nodes connected by phone lines
SRI940
UCLASigma 7
UCSBIBM 360
UtahPDP 10
IMPs
BBN team that implementedthe interface message processor
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ARPANet Evolves into Internet
Web HostingMultiple ISPsInternet2 BackboneInternet Exchanges
Application HostingASP: Application Service ProviderAIP: Application InfrastructureProvider (e-commerce tookit, etc.)
ARPANetSATNetPRNet
TCP/IP NSFNet Deregulation &Commercialization
1965 1975 1985 1995 2005
WWW
ISPASPAIP
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Parallel BackbonesQwest IP Backbone (Late 1999)Digex BackboneGTE Internetworking Backbone
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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
Jan. 2004 233,101,481
1
10
100
1000
10000
100000
1000000
10000000
100000000
1000000000
1981 1985 1989 1993 1997 2001
Data available at: http://www.isc.org/
Estimated number of users: http://www.internetworldstats.com/stats.htm
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Services Provided by the Internet
Shared access to computing resources- telnet (1970’s)
Shared access to data/files- FTP, NFS, AFS (1980’s)
Communication medium over which people interact- email (1980’s), on-line chat rooms, instant messaging (1990’s)- audio, video (1990’s)
• replacing telephone network? Medium for information dissemination
- USENET (1980’s)- WWW (1990’s)
• replacing newspaper, magazine?- Audio, video (late 90’s)
• replacing radio, CD, TV? - File sharing (late 90’s)
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BackboneISP
ISP
Internet Physical Infrastructure
Residential Access
- Modem- DSL- Cable
modem- Satellite
Enterprise/ISP access, Backbone transmission
- T1/T3, DS-1 DS-3
- OC-3 … OC-76
- ATM vs. SONET, vs. WDM
Campus network- Ethernet, ATM
Internet Service Providers- access, regional, backbone
- Point of Presence (POP)
- Network Access Point (NAP)
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RegionalNet
Regional Nets + Backbone
RegionalNet Regional
Net
RegionalNet Regional
Net
RegionalNet
Backbone
LAN LANLAN
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ISP
Backbones + NAPs + ISPs
ISP
ISPISP
BusinessISP
ConsumerISP
LAN LANLAN
NAPNAP
Backbones
Dial-up
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CoreNetworks
Covad
Core Networks + Access Networks
@home
ISPCingular
Sprint AOL
LAN LANLAN
NAP
Dial-up
DSLAlways on
NAP
CableHead Ends
CellCell
Cell
SatelliteFixed Wireless
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Covad
Computers Inside the Core
@home
ISPCingular
Sprint AOL
LAN LANLAN
NAP
Dial-up
DSLAlways on
NAP
CableHead Ends
CellCell
Cell
SatelliteFixed Wireless
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The Evolution of the Enterprise
Private CorporateNetwork
Dedicated facilities/computer centers
Dedicated applications/3rd party DBMS
E.g., Oracle
Late-1980sInternal users
Limited customer/external access
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The Evolution of the Enterprise
Private CorporateNetwork
Dedicated facilities/computer centers
Outsourced“Enterprise Resource
Planning” Appse.g., PeopleSoft, BAAN
1995Internal users
Limited customer/external access
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The Evolution of the Enterprise
OutsourcedWeb Hosting
Dedicated FacilityOutsourcedERP Apps
1997Internal users
Internet
External Customers
Virtual Private Network
ISP Mesh
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The Evolution of the Enterprise
OutsourcedWeb Hosting
Dedicated FacilityOutsourcedERP Apps
1997Internal users
Internet
External Customers
Virtual Private Network
ISPMesh
InternetServices
SearchCachingAdsEComm
Portal
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The Evolution of the Enterprise
ApplicationsService Provider
1999
Customers
Content Delivery “Net”
3rd PartyFacilities Mgmt
Caching +Media Servers
InternetServices
SearchCacheAdsEComm
OutsourcedWeb Hosting
Portal
ISP Mesh
VPNs
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Services Within the Network: Content Distribution
“Internet Grid”Parallel Network BackbonesInternet Exchange Points
Co-Location
Scalable Servers
WebCaches
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P2P Services in the Internet:Napster, Gnutella, Freenet, …
. . .
Madonna Like a Virgin
Madonna Material Girl
. . .
Directory Service
Register my copy
Find me a copy
Look here
Grid computing: sharing resources/enabling collaboration
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Services Within the Network:Streaming Media
Clients
Broadcasters
Content Broadcast
ManagementPlatform and
Tools
Steve McCanne
EdgeServers
Load Balancing ThruServer Redirection;
Content BroadcastNetwork
Content DistributionThrough MulticastOverlay Network
RedirectionFabricInter-ISP Redirection
Peering