CS4550:CS4550:

Computer Networks IIComputer Networks II

public telecommunication public telecommunication networksnetworks

“ “public” telecom networkspublic” 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 : historyUS telco networks : history

invention of telephone: ~1876 Alex. G. Bell, Elisha Gray, P. Reis original telephone patents: 1876,77 spread of telephone companies:

1893-4 to 1901 establishment of AT&T, its tactics,

monopoly in 3 areas

US telco networks : historyUS 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 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 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 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 loopsUS 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

phone

phone

PBX : private branch exchange 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 telco switch - generic design

controlunit

switching matrix

network interface

digital/analog devices trunks

...

... ... ...

US telco nets : structure < 1984 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 < 1984US 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 < 1984US 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 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, resultsAT&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 areaLATA 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 1984AT&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 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, UStelco 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 trendssome 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 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 comboTV cable -- long distance combo

TV cable network

ATT long distance network

cellular nets : wireless phones cellular nets : wireless phones

central station, and base stations

cellular nets : wireless phonescellular 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. satellite networks : iridium, etc.

iridium project : Motorola and others; already has 80-90 satellites in orbit

other competing will probably be expensive, but a

world-wide network for voice data

internet telephonyinternet 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 summaryinternational 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? 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