-MILNET- I ntroduction to Data Networks Introduction to ARPANET - PDF document

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

I~ 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 - Securely - Economically I I • I I INTRODUCTION TO ARPANET AND MILNET I ARPANET - Research and Development Since Late 1960s I MILNET ARPANET Military Network Network Research Network I I I {J I 2

Notes Network Overview-MILNET / ARPANET 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 3

II Network Overview-MILNET / ARPANET Notes • I P A C K E T S W I T C H I N G I N E T W O R K S • Common Network Serves Many Hosts and Users I • Computers Talk in Bursts and Want Fast Transfer, Low Delay • Packets Allow Efficient Sharing o I f Common Circuits • Store-and-Forward I I II THE A C C E S S I A N D B A C K B O N E N E T W O R K S I I I I B a c k b o n e Network I I , . 5

I Network Overview-MILNET / ARPANET Notes p I I THE BACKBONE NETWORK I • NODES • TRANSMISSION LINKS t I I • I 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 Notes Network Overview-MILNET / ARPANET 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 ~ ! I TAC 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

--- - .... • • ~- • I N E T W O R I < M O N I T O R I N G AND CONTROL: W H A T C O U L D G O W R O N G ? I • L i n e s G o D o w n or H a v e E r r o r s • P o w e r F a i l u r e a t t h e N o d e • N o d e S o f t w a r e o r H a r d w a r e F a i l s . • Host L o s e s Connection W i t h Network • T A C G o e s D o w n

II N e t w o r k O v e r v i e w - M I L N E T / A R P A N E T N o t e s I - .' I NETWORK MONITORING A N D CONTROL: WHAT COULD GO WRONG? I • Lines Go Down or Have Errors I • Power Failure at the Node • Node Software or Hardware Fails I • Host Loses Connection;)vith Network • T AC G o e s Down I I • I MC RESPONSIBILITIES I • User Assistance - Hotline for Questions and Problems • Isolating, Diagnosing and Correcting Problems I - Verifying the IMP Program - Reloading IMPs - Looping Lines I • Coordinating Overall Network Performance - Conducting Network Tests - Releasing New Software - Scheduling Preventative Maintenance • Measuring Network Performance - Monitoring Status Throughput Summaries - Compiling Reports • Maintaining the Network Controller's L o g I 10

I~ Notes Network Overview-MILNET / ARPANET !-. I-- NETWORK MONITORING CENTER (Artist's Concept) I I I I Located at BBN; Cambridge MA • I ARPANET AND MILNET HISTORY OF ARPANET I • 1960s ARPA (Advanced Research Projects Agency) Sponsored I Computer Time-Sharing Research at Leading Universities 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 12

Network Overview-MILNET / ARPANET Notes M I L N E T • W o r l d w i d e , U n c l a s s i f i e d N e t w o r k P r o v i d i n g D a t a C o m m u n i c a t i o n s B e t w e e n M i l i t a r y a n d O t h e r S e l e c t e d U s e r s - S e r v i c e s a n d A g e n c i e s O p e r a t i o n a l ADP S y s t e m s S p l i t F r o m A R P A N E T t o B e c o m e B a s e l i n e f o r M I L N E T - T o B e D i v i d e d I n t o O p e n a n d C l o s e d C o m m • u n i t i e s o f I n t e r e s t I • 6 5 N o d e s i n E u r o p e , t h e U . S . a n d the P a c i f i c - P l a n s f o r G r o w t h to 120 N o d e s • I I I ARPANET I • E x p e r i m e n t a l N e t w o r k - U t i l i z e d f o r C o m p u t e r N e t w o r k R e s e a r c h a n d to T e s t New C o n c e p t s to b e E m p l o y e d b y I t h e D O N • O v e r 100 C o m p u t e r s a n d 1 0 , 0 0 0 U s e r s M a k e Use o f t h e A R P A N E T - C a r r i e s a n A v e r a g e o f O v e r 2 0 M i l l i o n P a c k e t s P e r Day I I I rt 13

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 <D -+ ~ o -.. ARPANET GEOGRAPHIC MAP, SEPTEMBER 1982 A o < <D -.. < <D" I S r Z m --I '-. » HAWAII ::v ]; luHH.' Z m --I -' U1 -'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 -+ <D en .. - ... ...

.I~ ~N Network Overview-MILNET / ARPANET Notes i j I 0.. « ...1 00 « 0), u .... -0:: C)w oeo ~w w .... zc.. «w o..CI) a: « 16

Notes Network Overview-MILNET / ARPANET 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

., ...... ~ -1t'~ ~. -'~v ~,.,~ c:~:~ I[~ ~ ~ Bc~",dS":.",~5~-, ':'·Du~a! ~ "~'~: )I;; Z TI1non <D -+ 0 -.. A 0 < <D -.. < <D' HWAfII ... 0 ••••••• .... •.. : !'\ .... ' •••• .-I. I .' ..-:-::-...... Lowry AfII .. ' ...... ..... r Z ::- Pu .'vct ...... +--- bnttlcy AFB m ,"- -i 'j- Norfolk ··.0·: :r . ............. » A Ft. B.: .: '.t'- /:' ;V • _. O· • •• Ft. MIrPber~n .' .. obi/ns (f .... B ~ Z ... k ........ m ' ...... nvlll. , ..... .. -i ' 00 '-f· I C-·InAFB··. '.Otlando: " •••• ....... I) • ~ '0" .-\ ...... Randolph UB. • • KftOsl .. KFB : ;0 Existing Area Scheduled Network .. : =C\:::J . . z Q. <D en San Francisco Area