CS4550: Computer Networks II public telecommunication networks

“public” telecom networks “public” telecom networks  US telco networks : history, business, politics  US telco networks: basic structure  cable TV networks  wireless networks  international telephone networks  future (?) - fiber to the home?

US telco networks : history  invention of telephone: ~1876  Alex. G. Bell, Elisha Gray, P. Reis  original telephone patents: 1876,77  spread of telephone companies: to 1901  establishment of AT&T, its tactics, monopoly in 3 areas

US telco networks : history  hush-a-phone, pres. address, etc.  antitrust lawsuits : 1921, 1956, 1984  divestiture of 1984  other LD companies, Baby Bells, etc.  after 1984  1996: second divestiture and TC Act  recent events

US telco networks : business  generally very profitable, because - telephone service universal (in US) - local service companies often enjoy monopolies - ATT enjoyed 3 monopolies (<1984), protected by gov’t many years - ATT subsidized local service by overcharging on long distance (<84)

US telco networks : politics  often have had major influence on telecommunications industry - companies are very large, have many customers (voters) - telecom. essential to modern economy - control of communications is power (political, economic) - at times gov’t has protected monopolies; at times, divested them - antitrust laws

US telco nets : structure < 1984  ATT enjoyed monopolies in 3 areas: - local telco service - long distance - network equipment  telco network divided into 5-level hierarchy

US telco nets : local loops  local loop; “end office” or central office; star topology; app. 19K in US end office phone twisted pair to l.d. switch phone

PBX : private branch exchange  a privately owned telephone switch; enables companies, etc. to have own private local phone network  several generations; most recent are digital, capable of data and voice  connect to public telco through a “trunk,” or higher capacity line  centrex - similar service, but owned and maintained by the telco

telco switch - generic design control unit switching matrix network interface digital/analog devices trunks...

US telco nets : structure < 1984 regional switch (10) end office (19000) ATT l.d. structure < 84 -simple hierarchy, augmented by tandem lines -easy design, but not most efficient use of resources

US telco nets : structure < 1984  AT&T was major telco in US, largest in world (approximations below) -70% of local telephones in US - 99% of l.d. traffic - 99% telecom equipment - 1,000,000 employees - total revenue was 2% of annual GNP of US

US telco nets : structure < 1984  AT&T before 1984  22 BOCs (Bell Operating Companies) --> local telephone service  Western Electric --> equipment  Long lines department --> long distance service  Bell Telephone laboratories --> research lab “national resource”

AT&T : divestiture  background : 1956 consent decree  1974 : US DOJ brought suit against ATT for violation of antitrust law. Charged that ATT “denied benefits of free and competitive market to purchasers of telecommunications equipment and service”  settlement negotiated after years of negotiations and softball

AT&T divestiture, results  22 BOCs separated, grouped into 7 RBOCs  RBOCs to provide “equal access”  RBOCs may sell but NOT manufacture CPE  ATT retained WE, long lines, part of Bell labs  Bell labs split between ATT and RBOCs (Bellcore)  161 LATAs defined  ATT released from 1956 decree

LATA local access transport area  defines boundaries local telcos cannot cross; so 3 types of calls  local (truly local) - no charge ; Monterey to Monterey  local access : toll charge to local company (Monterey to Salinas)  long distance : must use a long distance company (Monterey - San Jose)

AT&T since 1984  l.d. share has decreased from 95%+ to ~60% or less, still quite profitable  employees --> ~300,000 (until 96)  ventured into computers - failed twice (ATT PC, NCR purchase)  bought out Craig McCaw’s cellular company -- > cellular network  gone to all digital network  2nd divestiture, 1996 (--> 180,000)  has agreement to merge with TCI

telecom since 1984  AT&T doing well, but only 1 of several major companies  Sprint, MCI major competitors after 84  Worldcom-MCI merger produced major telecom power  Lucent Tech. --> another power  telecom in other countries have moved towards competition, freedom  technology moved forward faster than ever before

telco companies today, US  ATT, Sprint, MCI-Worldcom ; GTE  original 7 RBOCs : Pacific Telesis; Nynex; Ameritech; US West ;Southwestern Bell (now SBC); Bell Atlantic;Bell South.  mergers have reduced these  SBC bought Pacific Telesis, and pending Ameritech  Nynex and Bell Atlantic merged  GTE may merge with Bell Atlantic

some current and future trends  all networks converging towards data networking (Internet)  i.e., voice, TV cable and internet become 1 network  TCI-ATT merger pending  Sprint-Cisco agreement on data network  will have higher bandwidth available to home & throughout

TV cable networks  designed for TV broadcast to homes  uses coaxial cable : 1 TV channel has 6 MHz, or 1500 voice channels; 1 cable can carry hundreds of channel  to carry voice/data, switching equipment needs to be modified.  TV networks can provide competition for voice, and higher speed internet access  ATT-TCI merger: ATT hopes to use TV cable for voice and data to penetrate home.

TV cable -- long distance combo TV cable network ATT long distance network

cellular nets : wireless phones  central station, and base stations

cellular nets : wireless phones  base stations communicate through radio signals with end users  competition for local phone and limited data. Has difficulties inherent in wireless media - inference, capacity, handoffs between cells; but these are being addressed.  security also more difficult

satellite networks : iridium, etc.  iridium project : Motorola and others; already has satellites in orbit  other competing  will probably be expensive, but a world- wide network for voice data

internet telephony  already here... will get better  quality less than conventional, but as speed improves, this will too  many parts of world have poor phone penetration; this may be the way to bring service, and break nationalistic monopolies (e.g., Telmex) and US telco monopolies

international telco summary  US most advanced, but western Europe, Japan, Taiwan, Hong Kong, Singapore, others close  much of world - India, China, Indonesia, Mexico/Latin America - far behind; some still have monopolies (e.g. Telmex)  some leading internat’l companies: Erricson, Deutche Telecom, British Telecom, Cable and Wireless, Hong Kong Telecom, NTT Lucent Tech., MCI-Worldcom, Sprint-Cisco, ATT, GTE, SWB

future : fiber to the home?  high capacity of fiber has drastically altered world of telecom  breakup of ATT 1984 has also drastically improved progress  fiber to the home? some predict this, may happen; but in whatever form, we can expect higher capacity internet and telephone access... possibly through TV cable... and continued progress in communications