Competition in Access

8/7/2019 Competition in Access

1/27

6.978/ESD.68Com pet i t ion in Ac c ess

N e t w o r k sSharon E. Gillett, MIT


2/27

The past : Si los

Broadcast

radio

Copper

POTS Cable TV

Coax

TV

Figur e 1: Past industry struc ture of resid ential access.

From (Clark, 1999)


3/27

The present :

Convergence

TV

Copper

POTS Internet

IAP

CLEC

Coax Wireless Satelli te

radio

Figur e 2: Emerging indus try structure of residen tial acc ess

VDSLADSL

HFC

Broadcast

From (Clark, 1999)

Th F t (?)


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The Fut ure(?):

In t ernet as Pla t form

Copper

POTS

Coax

Internet

IAP

Wireless Satelli te

radioPhone TVWebE-mail

Figur e 4: Poten tial indus try struc ture surround ing the Internet.

ADSL HFC

From (Clark, 1999)


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Wireless Telephony Competing With Fixed Lines, 2002

0

20,000,000

40,000,000

60,000,000

80,000,000

100,000,000

120,000,000

140,000,000

160,000,000

180,000,000

200,000,000

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 20020

20,000,000

40,000,000

60,000,000

80,000,000

100,000,000

120,000,000

140,000,000

160,000,000

180,000,000

200,000,000

AccessLine

s

Numbe

rofSubscribers

3 mil

Fixed Lines(1) Wireless(2) Broadband(3) Cable Telephony(4)

(1) 1990-1998 data from FCC Trends in Telephone Service May 2002; 1999-2002 data from FCC, Local TelephoneCompetition: Status as of Dec 31 2002; (2) CTIA Semi-Annual Wireless Industry Survey, published 2003; (3) 99-2001:FCC.COM: Trends in Telephone Service May 2002 (High Speed Lines with 200Kbps in at least one direction;Legg Mason Wood Walker, Inc. "Coming Down the Pipe - Interim Report 4Q 2002/1Q 2003 Industry Update - March13, 2003; (4) NCTA, "Residential Cable Telephony Subscribers


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0

5

10

15

20

25

30

Denm

ark

Nethe

rlands

Icela

nd

Korea

Switzerlan

d

Finla

nd

Norway

Swed

en

Canada

UnitedK

ingdom

Belgium

UnitedS

tates

Japan

Luxemb

ourg

Austr

ia

Fran

ce

Austr

alia

Germ

any

Spain Ita

ly

Portu

gal

NewZe

aland

CzechR

epub

lic

Irelan

d

Hungary

Polan

d

Turke

y

SlovakRepub

lic

Mexico

Gree

ce

Source: OECD

DSL Cable Other

OECD Broadband subscribers per 100 inhabitants, by technology, June 2006

OECD average

Courtesy of OECD. Source: OECD Broadband Statistics, http://www.oecd.org/sti/ict/broadband. OECD, 2006.


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7

3. BroadbandTechnolog ies

Courtesy of CSTB. Used with permission.


8/27

8

Net w ork Arc h i t ec t ure

Generic model of a broadband access network system architecture common across technology alternatives

important differences in cost-performance and business models

INTERNETINTERNET

Web Servers ,

e t c .

Acc ess Router /

Headend/Cache

Consumer Equipment

(wi red & w i re less)

Subscr iberInte r fa c e A c c e ss

Medium

(copper, coax ,

f iber , w i re less)

Mu l t ip lexed

broadband p ipe

w / aggregated da t a

IP packets

may be shared

or switched

IP packets

technology-specific

part of the system



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9

Wirel ine Opt ions

Hybrid fiber-coax DOCSIS

Role of fiber (toward FTTC)

Digital subscriber line (DSL) Distance, crosstalk

Role of fiber (toward FTTC)

Optical fiber Flavors of fiber to the home (FTTH)

Service based on equipment at both ends Depends on what kind of FTTH: not all the same

High-performance endpointhighest cost

Powerline



10/27

10

DSL/Fiber Arc hi t ec t ure

Same architecture evolves naturally from ADSL toVDSL to FTTC/FTTH

switching equipment tends to migrate closer to subscribers(..remote DSLAM, gigabit Ethernet switches, etc.)

system deployment cost dominated by physical wiring, due torapid improvements in switching & transport cost/performance

Acc ess Sw i tc h /Router w / cac hes

DSLAM or

Fiber Sw i tc h /

Concent ra to r

High-capac i t y f iber l ink

(ATM or IP/SONET, et c .)

Subscr iber

In te r facemay be placed

in remote location

or central officein-home

or curbside

t o m u l t i p le

ISPsfiber or

copper

pair



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11

HFC Arc h i t ec t ure

Broadband access over cable based on sharedaccess (DOCSIS standard) to existing TV coax

Medium access control (MAC) protocol for coax sharing

Signal converted to analog fiber at remote node

System cost dominated by fiber upgrade investments, due torapidly falling cost of DOCSIS modems & switching gear

Also evolves naturally towards FTTC/FTTH

IP Router &

cache

Cable Modem

Fiber

NodeHFC Analog Fiber Link

at remote

locations

in-homeshared

coax cable

DOCSIS

protocolsdata downstream

TV

data upstream

Aggregated

t ra f f i c

DOCSIS

head-end to In te rne t



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One Arc h i t ec t ure for BPL

IPL-modem

Backbone

network/

Internet

Tr

O/E

Distribution

substation CustomerLV networksOptical fiber

networks

IPL LANPoint-to-point

Link


13/27

13

Wireless Opt ions

Mobile/3G

Future: seamless mobile & portable broadband

Reality: emerging 3G falling short of hype (capacity, speed..)

WLAN 802.11, unlicensed 2.4 and 5 Ghz bands

Bottom-up deployment is accelerating... (airports, offices, homes..)

FWA (Fixed Wireless Access) MMDS, LMDS,...

much potential, but uncertain business conditions ...

Satellite Geo-synchronous (GEOS) & Low-earth orbit (LEOS)

Viable for certain markets, but with capacity limitations...



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14

Wireless Arc h i t ec t ure

Broadband wireless based on shared access ofradio medium (MMDS, LMDS, 3G, WLAN,..)

MAC protocol for shared use of radio (..similar to cable modems)

Switching or routing beyond access point (...similar to DSL)

FWA, satellite, WLAN & 3G/mobile as potential options, eachwith different entry cost and system cost/performance trade-offs

Wireless

subscr iber

In te r face

Fixed Wireless

or satellite

Wireless

Acc ess Po int

at remote

location

or CO

shared

wireless

medium

High-capac i ty f iber l ink

(ATM or IP/SONET, et c .)

radio

cell for

spatial

reuse

Mobile Wireless

(2.5G, 3G)

WLAN

Acc ess Sw i tc h /

Router w / cac hes

to m u l t i p le

ISPs



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15

Loc a l Ac c ess Tec hs in Cont ex t

Total cost and performance depends on more thanjust local access

Local access aggregates traffic from multiplepremises at POPs, funnels to higher-capacity links

Second mile connects to upstream aggregation Broadband providers pay for Internet transit service

or establish peering arrangements

Caches, service-supporting servers at POPs



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Unbund l ing DSL

After Fryxell, Sirbu, and Wanichkorn, 1999.

Access to

unbundled

loop (Full

unbundling)

Access tobitstream

IPGateway

Router CallServer

ATMSwitch

DSLAM

DSLAM

...

To Interoffice Transport

IP-based Central Office

POTS Customer

AnalogLines

DSLLines

Figure by MIT OCW.

DSL Customer


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Sub-loop Unbundl ing

Remote

electronics

Laser

transmitter

and receiver

Fiber feeder

Remote

electronics

Central

Office

Copper wire

pairs

ADSL S t All ti


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ADSL Spectrum Allocation

(Line Sharing)

POTS

10 KHz 50 KHz 1 MHz

Up stream channel

Downstream channel

Bidirectional


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Open Ac c ess and Layer ing

Layer: Municipality provides

0 Conduit and collocation facilities.

1 (PhysicalLayerUnbundling)

Dark fiber leasing, or perhaps, OpticalLayer unbundling (CWDM or DWDMin PONs)

2 (Data LinkLayerUnbundling)

Dark fiber and link-layer electronics ateach end. For example, Ethernet-based VLAN, or ATM-based PVCs.

3 (NetworkLayerUnbundling)

Basic network service provided. Forexample, IP Layer 3 service overcable using policy-based routing to

multiple ISPs


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Regulat ory Di lem m a

Heisenbergs Uncertainty Principle:

Cant observe situation without perturbing it

FundamentalEconomics

RegulatoryAssumption AboutCompetition

Outcome

Sustainable Free market

Not sustainable Regulation stifles

innovation, competition

Sustainable Government-sanctioned,unregulated monopoly

Not sustainable Necessarily regulatedmonopoly

Competition isnot sustainable

(no competitiveequilibrium)

Competition issustainable(competitiveequilibriumexists)


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Addi t iona l Tec h Sl ides

I t t A i C bl


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Int e rnet Ac c ess v ia Cable

Headend

IP router

TV channels

Data (LAN) channel

Rest of Internet

RF Modem

Translator

Data (LAN) channel

RF Modem

TranslatorConverter Converter

Local Loop Local Loop

Telephone


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IXC = Inter-eXchange

Carrier (longdistance

company)

LECswitching

office

inter-office transmission

"CITY"

LEC

switchingoffice

LEC = LocalExchange

Carrier (localtelephonecompany)

IXCswitch

IXCswitch

Inter-exchange ("long distance") network

LECswitching

office

inter-office transmission

"CITY"

LECswitching

office

Local LoopLocal Loop

Telephone

Network

Hierarchy

Twisted-pair copper

loops dedicated toindividual subscribers

Physical aggregation

at Central Office (CO)

via Main Distribution

Frame

CO Switching: Access

IXC Switching:Tandem

Increasing aggregation

at each level


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Mul t ip lex ing and

Conc ent rat ion in CO Sw i t c h

TDM

600

subscriberlines

8:1concen-tration

600 subscribers

(DS-3) 600 trunks

(5000 subscribers)

port

port

20-portswitchfabric

Splices represented by

Telephone


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Distribution cable

Drop

Drop

Distribution cable

Drop

Drop

Junction

Box

Junction

Box

Feeder cables

Drop

Drop

Distribution cable

Drop

Drop

Distribution cable

toward

Central

Office

Telephone

Access Network

Feeder

Distribution

Drop

Aggregation is physical:

bundles of wire-pairs

In t ernet over ADSL


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In t ernet over ADSL(w i t h VoIP)

After Fryxell, Sirbu, and Wanichkorn, 1999.

Access to

unbundledloop (Full

unbundling)

Access to

bitstream

IPGateway

RouterCall

Server

ATMSwitch

DSLAM

DSLAM

...

To Interoffice Transport

IP-based Central Office

POTS Customer

AnalogLines

DSLLines

Figure by MIT OCW.

DSL Customer

Te lc o m igrat ion t o


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Te lc o m igrat ion t o

Fiber- to- the-Neighborhood

Remote

electronics

Laser

transmitter

and receiver

Fiber feeder

Remote

electronics

CentralOffice

Copper wire

pairs

Documents

Competition in Access