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