CSE588: Network Systems

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23 Οκτ 2013 (πριν από 3 χρόνια και 5 μήνες)

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CSE588: Network Systems

Terry Gray*


Director, Networks & Distributed Computing

Affiliate Professor, Computer Science & Engineering


University of Washington


* and friends

Agenda


Week 1: Internet History and Basic Concepts

Week 2: Routing vs. Switching

Week 3: Architecture and Topology Trends

Week 4: Multimedia (QoS, CoS, multicast)

Week 5: ATM vs. IP

Week 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 Diagnosis

Week 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 Nuggets

continued



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 Internet

overview…


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 Fail

circa 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

Fail

circa 1997


Scaling:


Addresses,


Routing,


Bandwidth,


DNS


Function:


QOS,


Security

Why the Internet
might

Fail

non
-
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