TRIBAN Workshop Bern, 17-19 November 1998 Wiring (a small piece of) the world Target and interim...
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Transcript of TRIBAN Workshop Bern, 17-19 November 1998 Wiring (a small piece of) the world Target and interim...
TRIBAN WorkshopBern, 17-19 November 1998
Wiring (a small piece of) the world
Target and interim solutions
W. Warzansky
Telefonica I+D
TRIBAN WorkshopBern, 17-19 November 1998
Access network: target architectures
• From conclusions of former EURESCOM work,
later adopted by FSAN, it is considered that the
access network target architecture for broadband
interactive services in residential areas is
ATM-PON with ATM-PP as a variety.
• Full PON specification is now available (ITU-T G.983)
TRIBAN WorkshopBern, 17-19 November 1998
Present situation
• ATM-PON/PP deployment has not started, mainly because there is not yet a significant market for broadband interactive services.
• But there are already many access networks with a real, or latent, broadband capability:- Plain copper (POTS)
- Fibre access networks (active and passive)
- HFC
TRIBAN WorkshopBern, 17-19 November 1998
Evolution paths towards B-ISDN access networks
• EURESCOM (P-614) has performed a study of
possible (recommended) evolution paths from
existing access networks towards ATM-PON/PP,
with the aim of determining the possible
reutilization of part of the existing access
infrastructure.
TRIBAN WorkshopBern, 17-19 November 1998
Evolutionary paths
• From HFC to ATM-PON
• From existing fibre to ATM-PON/PP
• From existing copper to ATM-PON
• From existing copper to ATM-PON through LMDS
• ... and also, some interim solutions
TRIBAN WorkshopBern, 17-19 November 1998
From HFC to ATM-PON: step 1
Coaxdrop
PON
ONU
ANN/LTHE
duplexer return channel
E/OO
E/OO
TVset
set topbox
CPN
Cablemodem
Cablemodem
Port
To PC or LAN
TRIBAN WorkshopBern, 17-19 November 1998
Step 1: use of cable modems
• Deployment of cable modems and return path amplifiers
• Penetration level it can satisfy: around 1%
• Price tag: 670 Euro/user connected
TRIBAN WorkshopBern, 17-19 November 1998
Step 2: B-ISDN ONUs and coax reuse
Coaxdrop PON
(TV)ONU
LTHE
TVset
set topbox
CPN
NT
To LAN
OLTB-ISDN
ONU
Combiner
TRIBAN WorkshopBern, 17-19 November 1998
Step 2: B-ISDN ONUs and coax reuse
• Deployment of B-ISDN ONUs and NTs with coax line cards, combiners and return amplifiers (e.g., 620-860 MHz).
• ONUs fed by spare fibres or WDM
• Penetration level it can satisfy: up to 10%
• Price tag: 1150 Euros/user connected @penetration of 10%
TRIBAN WorkshopBern, 17-19 November 1998
Step 3: Enhancement of coax drop
• Upgrade of coax drop by replacing junction and distribution boxes. Deployment of extended band return amplifiers (e.g. 1-2 GHz).
• Price tag: increment from step 2 of 162 Euros/user connected.
TRIBAN WorkshopBern, 17-19 November 1998
From existing fibre to ATM-PON/PP
• Existing active fibre access networks are not standardised. There are many proprietary solutions deployed.
• Three starting situations have been considered:- PDH based active optical networks
- SDH based active optical networks
- Narrow band passive optical network
TRIBAN WorkshopBern, 17-19 November 1998
Example of SDH based AON
OLT
STM-1/ 4FMUX
FP2
drop sg.feeder
sectiondistribution segment
NT
STM-1
STM-1/4
L E X
SNI
A
D
M
A
D
M
A
D
M
FMUX
FP2
FMUX
NT
NTMLLN
TRIBAN WorkshopBern, 17-19 November 1998
Evolution paths for fibre based ON
• NB-PONs evolve naturally to ATM-PONs
• The recommended evolution of PDH AONs is to overlay an ATM-PP. Evolution to SDH is very expensive.
• For SDH based AONs:- Add B-ONU to N-ONU. Provide ADSL interfaces
- Overlay ATM-PP to ADMs
TRIBAN WorkshopBern, 17-19 November 1998
Enhanced SDH based AON
ATM
STM-1
POTS MUX ISDN II
xDSL ATM MUX
ATM NTxDSL
ONU-B
ONU-N
SNIs
STM-1
OLT-B
OLT-N
UNIs
Combined ONU
n x 2Mbit/s
Terminalmultiplexer
TRIBAN WorkshopBern, 17-19 November 1998
From existing copper to ATM
• xDSL from the exchange is NOT a long term solution- The bandwidth achievable in copper links is low
(probability of provision 15%)
- Noise from HDB3 (and others)
- Copper OAM costs are on the rising
- Very long payback time for new installation cables
- For high penetrations xDSL is more expensive than fibre
- Small number of DSL lines per cable
TRIBAN WorkshopBern, 17-19 November 1998
Step 1 (900 Euros/client)
V
Drop SegmentDistribution Segment
FP1
Twisted Pairs
Twisted Pair
Twisted Pair
MDF
DLCOptical Fibre
DLCODF
NB
BB
FP2
U T
DP
DP
DP
DP
DPATU-R+
SplitterMUX
DSLAM
FP2
MUX
POTSsplitters
DPATU-R+
Splitter
ATU-R+
Splitter
ATU-C
TRIBAN WorkshopBern, 17-19 November 1998
From copper to ATM: Step 2
• Option 1: Overlay ATM-PON for BB servicesPrice: 1150 Euros/client @10% penetration
• Option 2: Integrate NB and BB transport- Implement V5.x protocols in the ONU and use AAL1 for
transparent transport of 2 Mbit/s frames to NB switch
- Implement AAL2 at the ONU• Efficient bandwidth usage through VBR
• Supports voice compression
• Multiple voice channels on a single ATM connections
- Price: add 700 Euro/client @10% penetration
TRIBAN WorkshopBern, 17-19 November 1998
From copper to ATM: step 3
• The third step is to go all the way to ATM-PON with fibre deeper into the network and ONUs closer to the customer than in step 1
• Price: 1300 Euros/client @10% penetration
TRIBAN WorkshopBern, 17-19 November 1998
LMDS as an intermediate solution
• Starting situation: existing copper
• First step: LMDS
• Second step: augmenting LMDS
• Third step: ATM-PON
• The advantages of LMDS are those of wireless systems
TRIBAN WorkshopBern, 17-19 November 1998
1% 2% 3% 4% 5% 6% 7% 8% 9%10
%
11%
12%
13%
14%
15%
0%
30%
60%
90%
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
Cost Per Connected
Penetration
Interactivity
LMDS Cost: 1 Base Station
TRIBAN WorkshopBern, 17-19 November 1998
LMDS cost @10% penetration
10% Coverage
0
500
1,000
1,500
2,000
2,500
3,000
3,500
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Interactivity
TRIBAN WorkshopBern, 17-19 November 1998
Interim solutions
• Set of unconventional systems to deliver
somewhat more than NB but less than BB (e.g.,
200- 1000 Kbit/s)
• Some of these “interim solutions” look at
circumventing the existing fixed access
infrastructure, . . ., and the incumbent operator
TRIBAN WorkshopBern, 17-19 November 1998
Reflections on interim solutions
• Most of these “interim solutions” looks dubious,
at least now.
• Consequently, we heartily recommend them to
new entrant operators, though it seems unlikely
they will follow the recommendation.
• It seems advisable to keep an eye on these
solutions, because you never know what might
turn up
TRIBAN WorkshopBern, 17-19 November 1998
Low-cost XDSL implementations
• ADSL- wide variety of implementations and vendors
- HDSL (1- or 2-pairs) as symmetric counterpart
- medium/high maturity, medium cost, service limitations
- mostly rate adaptive and ATM based!
- provide both ATM and ATM interfaces
- typically PPP over AAL5
• CDSL (DSL lite)- widely discussed, little known
- uncertain maturity, low cost, major service limitations
- probably IP based
TRIBAN WorkshopBern, 17-19 November 1998
Example 1: Netspeed, key: modem sharing
POTS splitter
ATU-RDSLAM
ATU-C
ATU-C
ATU-C
Local Exchange Customer Premises
DSLAM = Digital Subscriber Line Access Multiplexer
ATU-C = ADSL Terminal Unit - Central side
ATU-R = ADSL Terminal Unit - Remote side
Off hookdetector
&Switch
Controller
n x m
n = number of ATU-C
m = number of ATU-R
n < m
TRIBAN WorkshopBern, 17-19 November 1998
Example 2: Paradyne, point-to-multipoint
DSLAM
ATU-C
ATU-C
ATU-C
ATU-R
ATU-R
ATU-R
sharedprinter
web server
Home Working
PC
4 kHz 20 kHz 100 kHz
broadband signalPOTS
DSLAM = Digital Subscriber Line Access MultiplexerATU-C = ADSL Terminal Unit - Central side
ATU-R = ADSL Terminal Unit - Remote side
Local Exchange Customer Premises
TRIBAN WorkshopBern, 17-19 November 1998
Example: CAIS system
NT
NT
NT
NT
OverVoiceEthernet
Hub
CC
MDF
twisted pair
fiber optical
Local Exchange Customer Premises
CC = Cross Connect
MDF = Main Distribution Frame
NT = Network Termination
Router
TRIBAN WorkshopBern, 17-19 November 1998
Powerlines
• Widely discussed, little proven, possibly expensive
• IP based, to overcome noise problems
• Further concerns- security aspects: maintenance of 240 V lines is
dangerous;
- privacy aspects: it is a physical bus, everybody receive everything (like in HFC networks);
- electromagnetic emission: possible noises produced by powerline systems affecting other electric devices (e.g. complaints from HiFi users);
- regulatory aspects: e.g. ownership of the lines.
TRIBAN WorkshopBern, 17-19 November 1998
Example: Nortel/Norweb approach
HV current
OLT
TxRx
Controller
TxRx
Powering
meter
TxRx
NT
NT
NT
NT
building meter
filter for inserting or extracting the BB signal
splitter
LV current
Router
Local Exchange Base Station and transformer
HV/LV transformer
power lines
Customer Premeses
low voltage power line (Cu)
high voltage power line (Cu)
fiber optic
coaxial cable
HV/LV = High Voltage / Low Voltage
OLT= Optical Line termination
NT = Network termination
TRIBAN WorkshopBern, 17-19 November 1998
Conclusions (I)
• The residential broadband interactive services
market has not yet arrived.
• One of the reasons for this (among others) is the
high capital investment required, in an
environment where capital investment goes to
acquisitions and home networks are under
intensive pressure to reduce costs.
TRIBAN WorkshopBern, 17-19 November 1998
Conclusions (II)
• Once way to reduce capital investment is to reuse
existing access infrastructure as much as
possible.
• EURESCOM has done this, studying how existing
access networks can be made to evolve gracefully
to ATM-PON, the already identified target access
network.