Networking vor dem Internet

1. Networking vor dem Internet Alex Zwahlen, HB9MKU Bern, 29 Oktober 2014

2. Zu meiner Person 1/2 • Ausbildung: • 1964-68: Lehre Elektronikgerätemechaniker (EGM) • 1968-71: HTL Burgdorf (Elektro - Schwachstrom) • 1972-73 Oy Strömberg AB (ABB) Finland • Minicomputer real-time applications design • 1974-94 Digital Equipment Corporation Europe • Tele-/Datacomm Tech. Support & Market Analysis • 1995-2006 AT&T International • Corporate Networking

3. Zu meiner Person 2/2 • 1974-78: DEC Datacomm applications support • Message (TTY) switches, IBM 360/370 Front ends • Batch Terminal emulators for IBM/CDC/UNIVAC • First DECnet products (Point-to-Point) • 1978-1982: DECnet III, X.25 • Packet Switching, Peer-to-Peer, Dynamic routing • 1982-1986: DEC: Office Communications • E-Mail, Videotex, Computer Integrated Telephony • DECnet: ISDN, X.21 integration • 1986-1990: DEC: Scientific/Academic Networks • ISO/OSI vs TCP/IP and their integration into DECnet • 1990-1994: DEC: Central & Eastern Europe Telecom • 1995-2006: AT&T: Global Corporate Networking

4. Main Topics • Data Communication Network Topologies • Hierarchical: Batch Terminal, Multiuser On-Line • Peer-to-peer: Distributed Computing • Timesharing and Message Switching • History of Packet Switching • X.25, Videotex, Ethernet • IBM’s SNA and DEC’s DECnet • Protocol Wars: ISO/OSI vs TCP/IP • Science & Academic networks

5. Early Data Processing • 1884: Punched Cards invented by Hollerith • 1911: Hollerith renamed “Computing Tabulating Recording Corporation (CTRC)”, then • 1924: “International Business Machines (IBM)” • 1964: IBM System/360 introduced • Remote Job Entry (RJE) via terminal IBM 2780 • 1974: RJE emulation with Minicomputers • E.g. DEC to IBM, to Univac, to CDC • File Transfer between heterogeneous systems!

6. Multi-user on-line computing • Multiple Users & Terminals on single system • Timesharing: Full system is shared among users • Program Development, Scientific computing • Typical Terminals were TTY, later glass-tube VDU • Point-to-point asynchronous • Transaction processing: limited functions for high number of users / terminals • Functions as defined by applications, typically against common database • Data Entry, Airline Reservation Systems, Banking, Retail • A typical terminal was IBM 3270 • Multipoint Synchronous (BSC protocol in 1967)

7. Remote Job Entry Terminals IBM 2780 RJE Terminal DEC PDP-11 2780 RJE Emulator

8. Local Area Connections • Local: typically same building, often same floor • To connect terminals to computer • Direct wired 4-20mA current loops • Via Data Switches (e.g. Gangdalf) • Multipoint/Multidrop serial lines (BSC) • To interconnect computer systems • Via (parallel-) channel interfaces • Very Vendor specific, some de-facto standards • E.g. the IBM/360 channel interface

9. Interactive Terminals TTY ASR33 IBM 3277 DEC VT52

10. Message Switching & SITA • 1837: Electric Telegraph for Railroad • 1933: 1st Telex Service in Germany • 1948: Store and Forward TWX – Reperforator • 1950: SITA opens Manual TTY center in Rome • 1966: SITA creates Computer based Store and Forward Message Center in Franfurt • 1969: SITA operates 1st worldwide PS VAN • PS VAN = Packet Switched Value Added Network • 1972: SITA spins off the VAN renamed Equant • 1999: France Telecom (ORANGE) buys Equant

11. Tymeshare & Tymnet • 1964: Tymshare Service Bureau created • 1979: Tymnet Value Added Net is spun off • 1984: McDD buys Tymnet -> MDNSC • 1989: BT buys MDNSC -> BT GNS • 1993-98: “Concert” joint venture BT + MCI • 1998-2003: break up - 5 years to separate networks! • MCI moves customers to TCP/IP • 2000-03: “New Concert” alliance BT + AT&T • 2004: BT shuts down last Tymnet supervisor…

12. History of Packet Switching 1/3 • 1958: DARPA created (after Sputnik shock) • 1960: SAGE + SABRE: TTY based communications • 1961: Sabotage of 3 Microwave Towers in US • US West-coast cut off for days • 1962: Basic Packet Switching Principles defined • P.Baran (US) objective: reduce vulnerability • D.Davies (UK) objective: share expensive links • Chop data in small blocks, route them individually over meshed networks to logical addresses • 1964: NPL and MIT launched PS experiments • 1965: 1st Peer-to-Peer cross-continental WAN • Arpanet precursor with NCP (Network Control Program)

13. History of Packet Switching 2/3 • 1969: 1st message over Arpanet, a remote login • 1969: SITA opens 1st worldwide PS VAN • 1971: CYCLADES (F) starts experimental datagram network (1981 forced to close by FT) • 1973: TCP/IP specifications, includes datagram concepts from CYCLADES (L.Pouzin) • 1974: L.Pouzin paper on “Interconnection of Packet Switched Networks” -> Internet • 1975: Arpanet size 99 computers (1980 = 200)

14. History of Packet Switching 3/3 • 1978: Cerf & Kahn publish stable TCP/IP specification • 1981: CSNET (Computer Science Net) created to avoid conflicts with ARPA. • 1981: BITnet created based on IBM’s VNET • Mainframes, File transfer, E-Mail • 1984: EARN = BITnet Europe • 1983: Arpanet migrates NCP to TCP/IP. • Splitting TCP and IP was critical to move to Internet • Internet = Network Interconnecting Networks • Example: “IP over Avian Carriers” (RFC 1149)

15. X.25 • X.25 design assumes error prone circuits • Corrects errors in the network • Mostly used with switched virtual circuits • 1980: Stable X.25 standard, used in Public nets • US: Compuserve, Tymnet, UK: PSS, F: Transpac, D: Datex-P, Telenet, etc. • X.25 made Mass-Terminal Nets cost-effective: • Cash-dispenser networks, Point-of-Sales • Videotex services (D: Btx, F: Minitel)

16. Videotex – precursor to WWW • 1983 Bildschirmtext (Telephony Approach) • All Data on “Btx-Zentrale” in Ulm (IBM based) • Pages are cached in regional centers • External Databases complex, only large companies could afford them (e.g. mail-order Quelle) • Btx -> Datex-J (1993) -> T-Online Classic (1995) • 1982-2012 Minitel (IT Approach) • Terminal connects to PAD on Transpac (X.25 net) • PAD connects via Transpac to Minitel Servers, • Servers can be any size, ideal for SME • 2000: 25Mio Users, 9Mio terminals, €1Billion/year • 1982: DEC VAX VTX: Corporate Videotex system

17. LAN Packet Switching - Ethernet • 1971: ALOHAnet: 1st public demo of Packet Radio • 1980: Ethernet standard available (CSMA/CD), developed during 1970’s by Xerox, Intel, DEC • 1981: 1st Ethernet products by 3-Com • 1983: DEC sells Ethernet, IBM announced TR

18. DECnet IV Peer-to-Peer Dynamic Routing (as in Internet) LAN’s Ethernet based 64’000 addressable nodes IBM SNA Terminal – Mainframe Strictly controlled by NCP LAN’s Token Ring TR Status 1983: DECnet vs IBM SNA

19. Science & Academic Networks • 1981: CSNET & BITnet created • 1983: UNIX (with free TCP/IP) spreads in S&A • Creates UNIX specific networked applications • UUCP mail & file transfer, newsgroups, bulletin boards • 1985: RARE (Réseau Associée pour la Recherche Européenne) created, promotes ISO/OSI • USEnet (UNIX), EARN (IBM), HEPnet & SPAN (DEC) • 1986: CSNET => NSFNET based on TCP/IP • Open to all S&A, creating TCP/IP market • 1990: European S&A officially supports TCP/IP • 1991: NSF lifts restrictions on commercial use • 1992: WWW/HTML, 1993 Mosaic browser

20. Large Distributed Computing Nets • DECnet • 1987: DEC EASYNET has 25’000 nodes • Internet has 28’000 hosts • 1990: HEPnet+SPAN have 20’000 nodes • Internet has 300’000 hosts • Gateways • 1983: HEPnet+SPAN to NSFnet/Internet • Full function • 1985 EASYNET-Internet for E-Mail, File x-fer • Important for Firewall Developments

21. First Abuses • 1978: 1st Spam mail: DEC to all on ARPANET • DEC sends DEC-20/ARPANET sales information • DEC blamed for “Commercial Abuse” of network • 1987: German (KGB) Hacker in sensible US Systems • Traced via Tymnet/Telenet and Dial-Up • Wake-up call for better authentication/protection • 1987: Christmas worm - BITnet, EARN, VNET • Infected IBM systems only • 1988: First Internet worm (Morris on UNIX) • Estimated 10% of 60’000 nodes attacked • 1989: DECnet worm in HEPnet/SPAN

22. ISO/Open Systems Interconnect • 1980: First OSI model published • 1988-95: Government OSI Profiles (GOSIP) • 1990: OSI in European Procurement Handbook and in US Federal Info Processing Standards (FIPS) • 1990: European Academics formally adopt TCP/IP • 1995: FIPS mandates no longer OSI, instead any ISO, ITU-T or IETF standards can be used • Why OSI didn’t succeed? • OSI too late, complicated, expensive, unproven • Euro Academic’s “supported” OSI mainly to get € • EDP suppliers “not really” supporting a 3rd stack

23. Frame Relay, ATM • FR designed during 1980’s for low error links • 1990 Gang of 4: Cisco, DEC, NT, Stratacom created FR Forum. Standards accepted in 1991 • Removed lots of X.25 error correcting overhead • DTE’s have to detect + correct errors, 56Kbps–45Mbps • QoS by Service Providers • 1993-98 Plusnet AG (CH + D) • ATM – Broadband ISDN • Low jitter, fixed 53 byte cells, • 34-155Mbps

24. International Network Alliances • Motivation: Single Point of Contact for • FR/ATM ports & PVCs, Access, On-Premise Routers • Unisource (1991-99) • KPN (NL), Televerket (S), Swisscom (CH), Telefonica (E) • AT&T (USA) in 1994 (AT&T – Unisource) • Concert (1993-2003) • 1993-98: British Telecom & MCI (USA) • 2000-03: British Telecom & AT&T (USA) • GlobalOne (1996 - 2000) • Deutsche Telekom, France Telecom, Sprint (USA) • Ended in 2000 when FT acquired Equant

25. International Corporate Networks • BMW 2000 • Domestic sites networked by Deutsche Telekom • Other countries by AT&T • Siemens 2003 • IT Network outsourced to AT&T and Telekom • Telekom: D, Eastern Europe, Italy, Nordic • AT&T: Rest of Europe & Worldwide • 2003+: VPN over Internet, ADSL access • No QoS, but cheap!

26. Cost-Example: Transatlantic Cable