A Personalized History of Computer Communications 1950s -1970s and Beyond Mischa Schwartz Charles Batchelor Professor Emeritus of Electrical Engineering Columbia University New York, NY 10027

1950s, 1960s US Defense Activity- SAGE Network, 1950s, Radar Data NIKE Zeus Data Network, AT&T Bell Labs, circa 1960 Paul Baran, Rand Corp., early 1960s, Survivable Data Networks Commercial Data Networking: Airlines, Banks, … Computer Time sharing Project Mac, MIT (GE Corp.), early 1960s

Commercial Data Networking, 1950s, 1960s Airline Reservation Systems American Airlines, LGA, 1952 American Airlines/IBM Sabre, 1959 IBM PARS, 1961 SITA, 1964 Banking Networks Ex: Lloyds Bank, UK, 1966 (IBM)

Airline Reservation Systems PARS, 1961 on SITA, 1964 on

Original PARS System

SITA Network

Banking Networks

Late 1960s to mid-1970s Private Data Networks- Tymnet, GE Information Services Network Proprietary Computer Communication Architectures (Computer Manufacturers) Ex: IBM SNA ARPA, ARPAnet

Private Data Networks, late 1960s-1970s Time-shared capability Terminal-oriented Data processing: Interactive, Batch processing Ex: GE Information Services Network TYMNET (Tymshare, Inc.) later- Networking functions

GE Information Services Network Centralized Hosts

TYMNET Distributed Hosts Virtual Routing

Computer Manufacturers, late 1960s on Teleprocessing Networks- Specialized Communication Controllers Proprietary Communication Architectures Ex: IBM SNA (later DNA, BNA,…) Specialized hardware, software Layered architecture

IBM SNA System Network Architecture: Layered Architecture

ARPA, ARPAnet: Formative Years 1962, MIT: J.C.R. Licklider, Globally interconnected computers Len Kleinrock, doctoral dissertation (1964, Communication Nets: stochastic message flow and delay, McGraw-Hill) 1965, Larry Roberts, MIT Lincoln Lab, interconnected-computer expt. Donald Davies, British NPL, packet message vs. packet switching

ARPA, ARPAnet: Network Concept/Development 1967, Roberts, ARPA: computer utility concept BBN contract, IMPs 1969, 4-node ARPAnet, datagram routing (1970, Host-to-Host protocol, NCP) Measurements- incestuous traffic! 1974, Robert Kahn and Vint Cerf- TCP (1978-TCP/IP) 24 node-ARPAnet 1976, 56 nodes

International Standardization Efforts Early 1970s, CCITT, public data networking 1976, X.25 Datapac (Canada), first public data network , ISO, OSI Reference Model: 7-layer communications architecture

X.25 Network-Interface Recommendation

OSI Reference Model Seven-Layer Architecture

ARPAnet Internet , TCP/IP adopted; replaces NCP 1985, 1986, NSFNET organized, regional nets encouraged: Ex: NYSERNET NSFNET expands, commercial service 1995 on: full-fledged Internet!

Internet and Beyond Millions of Hosts! Multimedia traffic Wireless connectivity: 3G cellular data, 4G all packet-switched all-purpose cellphones connections… Future? Your guess is as good as mine! But see following:

Focus on Personal Networks? Example: (with due respect to Magda!) MAGNET (European vision) My Personal Adaptive Global NET