Network Overview-MILNET / ARPANET
INTRODUCTION TO THE ADVANCED RESEARCH PROJECTS AGENCY NETWORK -ARPANET- AND THE MILITARY NETWORK -MILNET-
• I ntroduction to Data Networks • Introduction to ARPANET and MILNET • Components of the Networl< • ARPANET and MILNET
1 Network Overview-MILNET / ARPANET Notes I;)
INTRODUCTION TO DATA NETWORKS
I • Provide Data Flow Services to Users • Fast, Low-Delay Communications Between I People - People People - Computers I Computers - Computers - Speedily - Reliably
I~ - Securely - Economically I I
•I I INTRODUCTION TO ARPANET AND MILNET
ARPANET - Research and Development I Since Late 1960s
MILNET ARPANET I Military Network Network Research Network I I I {J
I 2 Network Overview-MILNET / ARPANET Notes 1
OBJECTIVES OF ARPANET
• Provide Efficient Communications Between Geographically Separated Heterogeneous Computers • Allow Convenient and Economical Sharing of Hardware, Software and Data Resources
•
COMPONENTS OF THE NETWORK
• Terminals • Host Computers
• Lines • Nodes (Switches)
• TACs • Network Management
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Network Network
THE THE
Overview-MILNET Overview-MILNET
• •
• •
• •
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Store-and-Forward Store-and-Forward
Packets Packets
Computers Computers
Common Common
Low Low
ACCESS ACCESS
PACKET PACKET
Delay Delay
Allow Allow
Network Network
Talk Talk
AND AND
SWITCHING SWITCHING
Efficient Efficient
in in
Serves Serves Bursts Bursts
/ /
BACKBONE BACKBONE
ARPANET ARPANET
Sharing Sharing
and and
Many Many
Want Want
5 5
of of
Hosts Hosts
NETWORKS NETWORKS
Common Common
Fast Fast
and and
NETWORKS NETWORKS
Transfer, Transfer,
Users Users
Backbone Backbone
Network Network
Circuits Circuits Notes Notes I Network Overview-MILNET / ARPANET Notes p I
I THE BACKBONE NETWORK I • NODES • TRANSMISSION LINKS t I I
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I THE BACKBONE NETWORK
IMP Interface Message Processor
• Interface Hosts to Backbone Network So That They Can Send and Receive Data Traffic • Act as a Tandem Switch So That Intransit Traffic Can Be I Properly Directed to Its Destination IMP
I pt
6 I Network Overview-MILNET / ARPANET Notes
IMP
• Dynamic Adaptive Routing • Automatic line Monitoring • End-to-End Error Control • Response to Failures/Congestion • Restart Procedures I I • DYNAMIC ROUTING • Route Around Outage or Congestion - vs. Predetermined or Fixed Route
7 Network Overview-MILNET / ARPANET Notes ,. \.9 ..'
TRANSMISSION LINKS
• Land-Analog (50 Kb; 9.6 Kb Europe) • Land-Digital (56 Kb) • Satellite and Submarine Cable • Microwave
THE ACCESS NETWORK
• Terminals That Use and Are Located at a Single Host Access Network Through Host Systems • Terminals That Use Several Hosts or Are Not Located Near Primary Host Access Network Through a T AC - Through Dedicated Circuit - Dial-Up a TAC Port
8 Network Overview-MILNET / ARPANET Notes
~ ! TAC I Terminal Access Controller
• BBNCC C/30. With 64 K Memory • Acts Like Telephone Switchboard - Connects Users to Any Authorized Host Computer I • Controls Access to the Networl< (via IMP) • Support Many Users on "1 Circuit" to IMP t • Network-Terminal Connection is Transparent
I • I CONNECTING TO THE REMOTE HOST
Computer in Los Angeles User in Boston
User's Procedures:
• Prepares His Terminal • Alerts the T AC • Logs on Host as User, When Connected • Continues Session as if Directly Connected to Host
9 ~- --- - .... •• •
NETWORI< I MONITORING AND CONTROL: WHAT COULD GO WRONG? I • Lines Go Down or Have Errors • Power Failure at the Node • Node Software or Hardware Fails . • Host Loses Connection With Network • T AC Goes Down
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NETWORK NETWORK
Overview-MILNET Overview-MILNET
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Maintaining Maintaining
Measuring Measuring
Coordinating Coordinating
Isolating, Isolating,
User User
- -
- -
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-
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-
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WHAT WHAT
Assistance Assistance
Compiling Compiling
Monitoring Monitoring
Scheduling Scheduling
Conducting Conducting
Releasing Releasing
Looping Looping Verifying Verifying
Reloading Reloading
Host Host
Node Node
Hotline Hotline
Power Power
Lines Lines
MC MC
AC AC
Diagnosing Diagnosing
Network Network
MONITORING MONITORING
Goes Goes
the the
Loses Loses
Software Software
Go Go
RESPONSIBILITIES RESPONSIBILITIES
Overall Overall
Failure Failure
for for
COULD COULD
Lines Lines
Network Network
New New
the the
Down Down
Reports Reports
IMPs IMPs
Down Down
Preventative Preventative
Status Status
Connection;)vith Connection;)vith
Questions Questions
Network Network
/ /
Performance Performance
IMP IMP
ARPANET ARPANET
at at
Network Network Software Software
and and
or or
or or
the the
Throughput Throughput
Program Program
Hardware Hardware
Controller's Controller's
Correcting Correcting
Have Have
GO GO
Node Node
Tests Tests
and and
Maintenance Maintenance
Performance Performance
Errors Errors
WRONG? WRONG?
AND AND
10 10
Problems Problems
Fails Fails
Network Network
Problems Problems
Summaries Summaries
Log Log
CONTROL: CONTROL: Notes Notes Network Overview-MILNET / ARPANET Notes !-. I-- NETWORK MONITORING CENTER (Artist's Concept) I I
I~ I I Located at BBN; Cambridge MA • I ARPANET AND MILNET I HISTORY OF ARPANET • 1960s ARPA (Advanced Research Projects Agency) Sponsored Computer Time-Sharing Research at Leading Universities I and Research Labs • These Projects and Their Computers Provided an Ideal . Environment for a Pilot Network Project • 1967 An Experimental R&D Network (ARPANET) Planned to Link These Computers - To Provide Efficient Communications Between Heterogeneous Computers, so That Hardware, Software and Data Resources Could Be Economically and Efficiently Shared by a Wide Community of Users I r'
11 Network Overview-MILNET / ARPANET Notes
HISTORY OF ARPANET (Cont)
• 1969 4 Nodes Installed and Operating
• Mid 1970s ARPANET Operational as Well as Experimental - Operational Responsibility Transferred to Defense Communications Agency (DCA) • 1983 DCA Divided ARPANET Into Two Separate Networks - MILNET - Unclassified Military Network -ARPANET - Continuing as a Facility for Network Research
PROBLEMS FACED IN DEVELOPING ARPANET
• Reliability • Allow Communication Between Computers of Varying Makes • Control Errors • Provide High Performance • Control Switching Remotely
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Network Network
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ARPANET ARPANET Over Over
Research Research
Experimental Experimental
• •
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-
65 65
Selected Selected
Communications Communications
Worldwide, Worldwide,
Overview-MILNET Overview-MILNET
100 100
Carries Carries
Nodes Nodes
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-
-
and and
Computers Computers
Plans Plans
of of
To To
Split Split
Services Services
an an
to to
Interest Interest
Users Users
Network Network
in in
Be Be
for for
Average Average
Test Test
From From
Europe, Europe, Unclassified Unclassified
Divided Divided
and and
Growth Growth
and and
New New
Between Between
ARPANET ARPANET
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Agencies Agencies
of of
ARPANET ARPANET
the the
10,000 10,000
Utilized Utilized
Into Into
Concepts Concepts
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Over Over
to to
MILNET MILNET
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Network Network U.S. U.S.
Open Open
ARPANET ARPANET 120 120
Military Military
20 20
Users Users
Operational Operational
and and
for for
to to
Nodes Nodes
to to Million Million
and and
Become Become
13 13
Computer Computer
the the
Providing Providing
be be
Make Make
and and
Closed Closed
Employed Employed
Pacific Pacific
Packets Packets
Other Other
Use Use
Baseline Baseline
ADP ADP
Communities Communities
Network Network
Data Data
of of
Systems Systems
the the
Per Per
by by
for for
Day Day
the the
MILNET MILNET
DON DON Notes Notes Network Overview-MILNET / ARPANET Notes
GROWTH OF ARPANET
1969 Supporting 4 Hosts 1971 Supporting 23 Hosts 1974 Supporting 62 Hosts 1977 Supporting 111 Hosts 1984 Supporting 350* Hosts
*Before ARPANET/MILNET Split •
•
14 ... • ., Z -'VVV SATElLITE CIRCUIT • C:30 IMP o 316 TAC l:J. C'30 TAC NO IE THIS MAP ODES NOT SHOW ARPA'S FXPERIMENT Al SATEllITE CONNECTIONS. NAMES SHOWN ARE IMP NAMFS, NOT INECESSARll VI HOST NAMES T1NK{R- OKLAHOMA CITY z o-+ .~--~ .. - ...~-~ ...-~~-.----~---~- Network Overview-MILNET/ ARPANET Notes i j I «0.. ~N ...1 00 « 0), u .... -0:: C)w oeo ...I~ ~w zc..w .... o..CI)«w a: « 16 Network Overview-MILNET / ARPANET Notes ARPANET HOST ADMINISTRATOR • Actas Advisors to Network Users, MC, Network Information Center (NIC) and DCA • Each Host Has Only One • First Point of Contact for Most ARPANET Users • Monitor ARPANET Against Unauthorized Use I SECURITY • Unlike MILNET, ARPANET Communications Backbone Contains No Security Features to Insure Privacy or Protection of Information Transiting the Network ) 17 ., )I;; ...... Z .. ' ~ ...... ~,.,~~~ ..... ~. r ...... ::- Pu .'vct Z +--- bnttlcy AFB m ," -i . ··.0·:'j- :rNorfolk ...... : A Ft. B.: '.t'- /:' ;V» • _. O· • •• Ft. MIrPber~n .' ..obi/ns (f .... B ~ ... k ...... Z ' ...... nvlll. , m ..... -i 00 .. ' "~'~: " I •••• '-f· ...... C-·InAFB··. '.Otlando:I) ...... --1t'~ Randolph UB. • • KftOsl .. KFB • ~'0" .-\ -'~v c:~:~ :I[~ ;0 ~~ Existing Area Scheduled Network ...: .=C\:::J z Q. Bc~",dS"::.",,~5~~--, i. . _. g . _Ii X Network Overview-MILNET / ARPANET Notes EkhoDAFB .? .. Greely ••• : ·.0 .... : ...... ...... ' ..' ...... ' .. , ...... ' ...... ' .' .' .. .' .' Humosa ~ ...... 6: ·0...... ft. Buckner : ...... : I" ...... ' .' .' . . M ..' .. ' .. ' • • Existing Network I Y ... ' .. 0" •••• ··0 Scheduled Network Clark A.FB .. " I .. " \ ~.:./...... 'l~0 .. ~...... ' Land"~ •••••••• ••••••••••••••••••••••••••• 0 ••• •• V ~ "'. nti Flol':ga)"an 19 Network Overview-MILNET / ARPANET Notes Berlin ...... ·0 I o .... --... Existing Area o· .... ··0 Scheduled Network I ~ 20