CSE588: Network Systems
Terry Gray*
Director, Networks & Distributed ComputingAffiliate Professor, Computer Science & Engineering
University of Washington
* and friends
Agenda Week 1: Internet History and Basic Concepts
Week 2: Routing vs. SwitchingWeek 3: Architecture and Topology TrendsWeek 4: Multimedia (QoS, CoS, multicast)Week 5: ATM vs. IPWeek 6: Routing part 1 (Intro, RIP, OSPF)Week 7: Routing part 2 (BGP, state of the Internet)Week 8: TBD --Guest lecture(s) Week 9: Failure Modes and Fault DiagnosisWeek 10: Product evaluation criteria
Non-Agenda
• Tutorial on Networking Fundamentals
• Protocol Design
• Device Design
• Network Programming
• Network Modeling/Analysis
The Plan
• Focus on Internet technology from network practitioner’s perspective.
• Focus on enterprise and wide-area issues.
• Use commodity Internet and UW campus network as case studies.
• Discuss and debate alternatives!
Week 1: Background
• Networking Fundamentals
• The Internet: Past, Present, Future
• UW’s Intranet: Past, Present, Future
Networking Fundamentals
• Terminology
• The Reference Model(s)
• The Great Debates
• Conventional Wisdom
• Gray’s Networking Nuggets
• Some Research Questions
Terminology• Open• LAN, CAN, MAN, WAN... VLAN, ELAN• TCP/IP• Internet, Intranet• Packet, Message, Circuit Switching• Frame, Cell• Repeater, Bridge/Switch, Router• MAC Address• IP Address• ATM
The Infamous OSI REFERENCE MODEL
Version 1
• 7 Application
• 6 Presentation
• 5 Session
• 4 Transport
• 3 Network
• 2 Link
• 1 Physical
The Infamous OSI REFERENCE MODEL
Version 2• 10 Religious <--- You are here• 9 Political• 8 Economic• 7 Application• 6 Presentation• 5 Session• 4 Transport• 3 Network• 2 Link• 1 Physical• 0 Cable Plant
The Internet Reference Model
• 5 Application e.g. HTTP
• 4 Transport e.g. TCP
• 3 Network i.e. IP
• 2 Link e.g. Ethernet
• 1 Physical e.g. Fiber
Internet Protocols by Layer
• Application: HTTP, FTP, Telnet, NFS, IMAP, etc
• Transport: TCP, UDP, RTP
• Network: IP (ICMP, IGMP, DHCP, OSPF)
• Link: ARP, RARP
Layers vs. Interoperability
L1
L2
L3
L4
L5 Application
Transport
Network
Link
Physical
OS BB
Conventional Wisdom
• 1988: OSI will replace TCP/IP
• 1992: Cat 3 wire will never carry 10Mbps
• 1995: ATM will replace TCP/IP
• 1995: ISDN will be pervasive
• 1997: VLANs will replace routers
• 1997: Telco competition will reduce costs
The Great Networking Debates circa 1992
• Ethernet vs. Token Ring
• Routers vs. Bridges
• Multi Protocol vs. Single Protocol
• FDDI vs. ATM
• TCP/IP vs. OSI
The Great Networking Debates circa 1997
• Ethernet vs. ATM
• Routers vs. Switches
• Multi Protocol vs. Single Protocol
• TCP/IP vs. ATM
Design/Deployment Questions
• Requirements (protocols, applications)
• Architecture (Topology, technology)
• Routing vs. switching vs. hybrids
• Device evaluation criteria
• Multimedia (QoS, CoS, multicast)
• ATM vs. Fast/Gigabit Ethernet
• IPv6
Gray's Networking Nuggets
• KISS-1: Keep It Simple, Stupid “Heterogeneity always costs more than you think it will”
• KISS-2: Keep It Separate, Stupid “Good fences make good neighbors”
• The last art is the art of glumping
• Design for high-availability... but beware the dark side of Redundancy
• Technology rots: don't buy it before you need it
Gray's Networking Nuggetscontinued
• “Trust but Verify”… "Acid indigestion? Check your source.”
• Beware standardization by government edict (Ada, OSI, X.400)
• Standardization always happens too soon technically, but too late practically
• "Conventional Wisdom" is completely orthogonal to "Wisdom"
Research Questions
• Performance:– Transient delay analysis tools– Multi-layer congestion control effects– QOS and COS– TCP, RTP, etc, design improvements
• Topology: Hierarchy, mesh, lattice, ring
• Security: Infrastructure, session/packet
End of Fundamentals
• If the terminology is unfamiliar, hit the books!
• Discussion?
• Next up:
30 years of the Internet in 30 minutes
The Internet: Past, Present, Future
• Introduction
• History
• Issues
• Summary
Introduction: How many of you...
• Use Email almost every day?
• Use the Web almost every day?
• Consider yourself an "Internet Junkie"?
• Plan to become one Real Soon Now! ?
• Have seen a TV documentary on the Internet?
• Know what the ARPANET was?
• See the 'Net as a Really Big Deal?
My view of the Internet:
• A powerful tool, with both good and bad uses.
• An unparalleled sociological phenomenon.
• Both a trigger and a medium for defining 21st century values.
• Some pretty interesting technology.
POP QUIZ #1 ( True or False):
• The ARPANET was designed to be a military command/control network that could survive nuclear war.
• Packet switching technology was chosen for ARPANET primarily because of its ability to go around faulty portions of a net.
• Packet switching technology was one of the most important achievements of Bell Labs, and AT&T was an enthusiastic partner in the ARPANET project.
• Computer Scientists at major universities were universally supportive of the ARPANET, unlike those at smaller schools.
POP QUIZ #1 ( Cont’d):
• The World Wide Web was invented at CREN (the Corporation for Research and Educational Networking)
• Email was one of the prime motivators for the net.
• Unlike the telecommunication industry, the computer industry quickly adopted Internet standards in their quest to provide open systems.
• Restricting use of encryption on the Internet will ensure that communication remains open.
POP QUIZ #2 (True or False):
• ARPA projects led not only to today's Internet, but also to
cellular telephone and Ethernet technology.
• The Web is not the Internet.
• The Internet will eliminate many jobs.
• The Internet will create many jobs.
• The Internet is a powerful tool for world peace.
• The Internet is a powerful tool for Western Imperialism.
• In the Internet, the U.S. Constitution is a local ordinance.
The History of the Internetoverview…
• 1960s: The Vision > Remote Resource Sharing
• 1970s: Making it Work > Packet switching, LANs, Internets
• 1980s: Widespread Deployment > NSFnet, Bitnet, CSnet, Usenet, Fidonet
• 1990s: Success Problems > Scaling, Navigation, Filtering, Politics, Economics
The History of the Internet highlights…
• 1962: Dr. Licklider goes to Washington• 1966: Bob Taylor has too many terminals on his desk• 1969: ARPANET begins (also Woodstock, Apollo 11)• 1972: ARPANET and ALOHANET interconnect• 1973: Metcalf/Boggs develop Ethernet from Alohanet • 1974: Cerf/Kahn publish TCP/IP specification• 1977: TCP/IP demo: ARPANET, SATNET, PRNET,
Ethernet
The History of the Internet highlights cont’d…
• 1979: USENET (distributed BBS) begins• 1981: BITNET, CSNET, Minitel begin• 1983: ARPANET cutover to TCP/IP completed• 1986: NSFNET begins• 1988: The Internet Worm attack• 1990: ARPANET ends • 1991: World Wide Web invented• 1993: NCSA Mosaic released• 1995: NSFNET ends, Netscape goes public
Why the Internet will Failcirca 1992
• "TCP/IP is a sunset technology"
• "You can't use TCP/IP for mission critical applications"
• "TCP/IP can't go very fast"
• "FTP will corrupt complex data files"
• "You can't do multimedia over SMTP"
• "TCP/IP is a proprietary protocol developed by DOD"
• "The Internet standards process is not open”
Why the Internet might Failcirca 1997
• Scaling: – Addresses, – Routing, – Bandwidth, – DNS
• Function: – QOS, – Security
Why the Internet might Failnon-technical issues
• Threats from policy problems:– Usage: Censorship, Copyright, Spam/junk– Micro-economic: distance/time/usage pricing– Macro-economic: Haves/HaveNots, Investment
• Threats to individuals:– Privacy: Exposure of info, usage patterns– Addiction: impact on social contact/activities– Productivity: signal-to-noise ratio
More Internet concerns...
• Threats from crime:– Real crime: technology helps the bad guys, too.– Pseudo-crime: misguided legislation
• Threats to organizations: – Open communication– No hierarchy
• Threats to business: – Some middlemen will be toast– Legal liabilities will stifle some businesses
More Internet concerns...
• Threats to scholarly quality:– Content: lots of junk, lots of old versions– Searching/catalogs: best stuff may never be found
• Shared files/authorship: coordination problems
The NSFnet is Gone
• NSFnet ceased to exist 30 April 1995
• Initially a non-event, but trouble followed.
• There is no longer *a* national backbone
• MCInet is now carrying >> max NSFnet traffic
• MCInet traffic doubling every 4-6 months
• MCInet backbone: DS-3 to OC-3 to OC-12
• Extrapolation to 2000: Need OC192
The Internet Goes P.C.
• PC = Personal Computer:– Nov 1994: Bill Gates announces 2 initiatives:
• Investment in UUNET
• Reorientation of Microsoft Network
• PC = Politically Correct:– Oct 1996: Bill Clinton announces 3 initiatives:
• Internet II
• Next Generation Internet
• Internet 2000
INTERNET II ?
• Is this a government or Higher-Ed initiative?
• What are the goals?
• Will commercial net providers meet Higher-Ed needs?
• How do Higher-Ed needs differ from, say, Chrysler's?
• Will "Virtual University" needs force dedicated net?
• Would it even help to have a Higher-Ed net?
Summary: The Internet...
• Is an amazing tool and an amazing phenomenon.
• Tends to eliminate time, distance, and rank.
• Breeds misinformation on and about it.
• Faces challenges that are growing exponentially.
• Brings opportunities that are growing exponentially.
• The hardest problems ahead are not technical (but there are some dandy technical problems, too!)
End of Internet: Past, Present, Future
• At least, from a non-technical perspective!
• Discussion?
• Next up: UW Network Overview
UW’s Intranet: Past, Present, Future
• Environment
• Growth
• Key Decisions
• Topology
UW Network: Environment
• 1988: five anti-interoperable campus nets...– 3,000 machines on a bridged Ethernet– A large Micom terminal network– Separate library, hospital, and administrative nets
• 1997: one campus net with...– 12,000 PCs– 6,000 Macs– 4,000 Unix workstations– 3,000 X terminals– 1,000 hubs, routers
UW Network: Growth
• By 12/94 we had 17,000 nodes and 650 modems
• By 12/95 we had 22,000 nodes and 1,300 modems
• By 12/97 we had 27,000 nodes and 1,500 modems
• Run-rate had been 3k/yr nodes, now flat… > Saturation at last??
UW Network: Key Decisions
• Use Internet standards
• Route only IP
• Use lots of subnets
• Use lots of 10BaseT Ethernet
• Move to dedicated/switched 10
UW Network: Backbone Topology
• Epoch 1 (c. 1989): Dual Shared Ethernet Backbones
• Epoch 2 (c. 1992 ): Dual Routers
• Epoch 3 (c. 1995): Quad Ethernet Switches
• Epoch 4 (c. 1998): Quad Fast Ethernet Switches
End of UW Network Overview
• Stay tuned for more on UW network issues!
• Discussion?
• Next up: – Week 2: Switching and Routing
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