NETWORK MIGRATION TECHNICAL REPORT Page 1 of 57 ADSLForum TR-004, issue 1
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`NElWORK MIGRATION TECHNICAL REPORT
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`Page 1 of 57
`ADSLForum TR-004, Issue 1
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`Technical Report
`Technical Report
`TR-004
`TR-004
`Network Migration
`Network Migration
`
`5
`
`1997
`December
`December 1997
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`10
`
`ABSTRACT:
`
`10 ABSTRACT: This project describes network migration options for telco access networks incorporating ADSL. Different telcos will 15 have different legacy systems, regulatory and competitive environments, broadband strategies and deployment timescales. Hence it is not feasible to make all encompassing recommendations for network migration options. This project seeks to capture the drivers that may lead a telco to consider a particular migration path. lt then presents the various technical options together with the salient features, advantages and disadvantages to assist telcos in forming evolution plans for an access network that will incorporate ADSL. lt is hoped that this working text will serve as a 20 useful reference text for both the technical and marketing professionals in the ADSL Forum.
`
`This project describes network migration options for telco access networks incorporating ADSL. Different telcos will
`have different legacy systems, regulatory and competitive environments, broadband strategies and deployment
`timescales. Hence it is not feasible to make all encompassing recommendations for network migration options. This
`project seeks to capture the drivers that may lead a telco to consider a particular migration path. It then presents the
`various technical options together with the salient features, advantages and disadvantages to assist tel cos in forming
`evolution plans for an access network that will incorporate ADSL. It is hoped that this working text will serve as a
`useful reference text for both the technical and marketing professionals in the ADSL Forum.
`
`15
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`20
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`5
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`NETWORK MIGRATION TECHNICAL REPORT
`NElWORK MIGRATION TECHNICAL REPORT
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`Page 2 of 57
`Page 2 of 57 ADSLForum TR-004, Issue 1
`ADSLForum TR-004, Issue 1
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`Network Migration
`Network Migration
`TR-004
`TR-004
`1997
`December
`December 1997
`©1997 Asymmetric Digital Subscriber Line Forum. All Rights Reserved.
`ADSL Forum technical reports may be copied, downloaded, stored on a server or otherwise re-distributed in their
`entirety only.
`
`5
`
`01997 Asymmetric Digital Subscriber Line Forum. All Rights Reserved. 5 ADSL Forum technical reports may be copied, downloaded, stored on a server or otherwise re-distributed in their entirety only. Notwithstanding anything to the contrary, The ADSL Forum makes no representation or warranty, expressed or implied, concerning this publication, its contents or the completeness, accuracy, or applicability of any information 10 contained in this publication. No liability of any kind shall be assumed by The ADSL Forum as a result of reliance upon any information contained in this publication. The ADSL Forum does not assume any responsibility to update or correct any information in this publication. The receipt or any use of this document or its contents does not in any way create by implication or otherwise any 15 express or implied license or right to or under any patent, copyright, trademark or trade secret rights which are or may be associated with the ideas, techniques, concepts or expressions contained herein.
`
`Notwithstanding anything to the contrary, The ADSL Forum makes no representation or warranty, expressed or
`implied, concerning this publication, its contents or the completeness, accuracy, or applicability of any information
`contained in this publication. No liability of any kind shall be assumed by The ADSL Forum as a result of reliance
`upon any information contained in this publication. The ADSL Forum does not assume any responsibility to update
`or correct any information in this publication.
`
`The receipt or any use of this document or its contents does not in any way create by implication or otherwise any
`express or implied license or right to or under any patent, copyright, trademark or trade secret rights which are or may
`be associated with the ideas, techniques, concepts or expressions contained herein.
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`10
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`Page 3 of 57
`NETWORK MIGRATION TECHNICAL REPORT Page 3 of 57 ADSLForum TR-004, Issue 1
`ADSLForum TR-004, Issue 1
`NETWORK MIGRATION TECHNICAL REPORT
`
`TABLE OF CONTENTS
`TABLE OF CONTENTS
`
`1. STATEMENT OF PROJECT
`1. STATEMENT OF PROJECT
`
`INFLUENCING MIGRATION TO ADSL
`2. FACTORS
`2. FACTORS INFLUENCING MIGRATION TO ADSL
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`6
`6
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`6
`6
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`NETWORK/ARCEITECITJRERELATEDFACTORS
`2.1 NETWORKIARCIDTECTURE RELATED FACTORS
`
`~.~EQUIPMENTRELATEDFACTORS
`2.2 EQUIPMENT RELATED FACTORS
`
`2.3 BUSINESS/SERVICE RELATED FACTORS
`2.3 BUSINESS/SERVICE RELATED FACTORS
`
`3. ACTIVE AND PASSIVE NT ISSUES
`3. ACTIVE AND PASSIVE NT ISSUES
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`6
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`7
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`8
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`8
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`STAND-AL~NEACTIVENTADSL REMOTEUNIT
`~.~ADVANTAGESOFA
`3.1 ADVANTAGES OF A STAND-AWNE ACTIVE NT ADSL REMOTE UNIT
`
`ADVANTAGES OF A PASSIVE NT WITH ADSL REMOTE UNIT EMBEDDED IN CPE
`3.2 ADVANTAGES OF A PASSIVE NT WITH ADSL REMOTE UNIT EMBEDDED IN CPE
`
`9 3.2
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`6 6.5
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`5
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`10
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`15
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`4. CLASSIFICATION OF MIGRATION OPTIONS
`4. CLASSIFICATION OF MIGRATION OPTIONS
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`5. OVERVIEW OF MIGRATION OPTIONS RELATIONSHIP
`5. OVERVIEW OF MIGRATION OPTIONS RELATIONSHIP
`
`6. DESCRIPTION OF POTENTIAL MIGRATION PATHS
`6. DESCRIPTION OF POTENTIAL MIGRATION PATHS
`
`~.~INTERNET ACCESS:VOICEBAND MODEMTOADSL MODEM
`6.1 INTERNET ACCESS: VOICEBAND MODEM TO ADSL MODEM
`6.1.1
`6.1.1 Starting Network Scenario
`6.1.2 Target Network Scenario
`6.1.3 Drivers
`6.1.4 Options
`6.1.5 References
`
`PAIR-GAIN PROVIDED POTS TO ADSL
`6.2 PAIR-GAIN PROVIDED POTS TO ADSL
`6.2.1
`20 6.2
`20
`6.2.1 Starting Network Scenario
`6.2.2 Target Network Scenario
`6.2.3 Drivers
`6.2.4 Options
`
`CO-BASED ADSL TO NGDLC-BASED ADSL
`6.3 CO-BASED ADSL TO NGDLC-BASED ADSL
`6.3.1
`25 6.3
`25
`6.3.1 Starting Network Scenario
`6.3.2 Target Network Scenario
`6.3.3 Drivers
`6.3.4 Options
`6.3.5 References
`
`30
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`35
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`30 35 6.4
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`ISDN TO ADSL FOR INTERNET ACCESS
`6.4 ISDN TO ADSL FOR INTERNET ACCESS
`6.4.1
`6.4.1 Starting Network Scenario
`6.4.2 Target Network Scenario
`6.4.3 Drivers
`6.4.4 Options
`6.4.5 References
`
`ADSLIN AN ATMNETWORK: FROMINTERNETONLYTOFULLSERVICE
`6.5 ADSL IN AN ATM NETWORK: FROM INTERNET ONLY TO FULL SERVICE
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`Starting Network Scenario
`6.1.2 Target Network Scenario
`6.1.3 Drivers
`6.1.4 Options
`6.1.5 References
`Starting Network Scenario
`6.2.2 Target Network Scenario
`6.2.3 Drivers
`6.2.4 Options
`Starting Network Scenario
`6.3.2 Target Network Scenario
`6.3.3 Drivers
`6.3.4 Options
`6.3.5 References
`Starting Network Scenario
`6.4.2 Target Network Scenario
`6.4.3 Drivers
`6.4.4 Options
`6.4.5 References
`2.1
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`6.5.1 Starting Network Scenario
`6.5.2 Target Network Scenario
`6.5.3 Drivers
`6.5.4 Options
`6.5.5 Summary
`6.5.6 References
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`25
`26
`27
`28
`39
`39
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`TO"FULL SERVICE"SETVIA
`INTERNETONLY VIA
`6.6 INTERNET ONLY VIA "IP" ADSL TO "FULL SERVICE" SET VIA ATM ADSL
`6.6.1 Starting Network Scenario
`6.6.2 Target Network Scenario
`6.6.3 Drivers
`6.6.4 Options
`
`40
`40
`40
`41
`41
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`ATM ADSL 40 6.6.1 Starting Network Scenario 40 6.6.2 Target Network Scenario 40 6.6.3 Drivers 41 6.6.4 Options 41 6.7
`
`TO “FULL SERVICE"
`INTERNET ONLY VIA
`6.7 INTERNET ONLY VIA "IP" ADSL TO "FULL SERVICE" SET VIA "IP-ONLY" ADSL
`6.7.1 Starting Network Scenario
`6.7.2 Target Network Scenario
`6.7.3 Drivers
`6.7.4 Options
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`SET VIA “IP-ONLY” ADSL 41 6.7.1 Starting Network Scenario 41 6.7.2 Target Network Scenario 42 6.7.3 Drivers 42 6.7.4 Options 42 6.8 ADSL SERVICE DELIVERY TO VDSL SERVICE DELIVERY 43 6.8.1 Starting Network Scenario 43 6.8.2 Target Network Scenario 43 6.8.3 Drivers 44 6.8.4 Options 44 6.8.5 References 46 6.9 NGDLC-Based ADSL to ONU-Based ADSLNDSL 47 6.9.1 Starting Network Scenario 47 6.9.2 Target Network Scenario 47 6.9.3 Drivers 48 6.9.4 Options 49 6.9.5 References 49 6.10 VDSL FOR RESIDENTIAL SERVICES TO VDSL FOR
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`NETWORK MIGRATION TECHNICAL REPORT Page 4 of 57 ADSLForum TR-004, Issue 1 5 10 15 20 25 30 35 40 45 6.5.1 Starting Network Scenario 25 6.5.2 Target Network Scenario 26 6.5.3 Drivers 27 6.5.4 Options 28 6.5.5 Summary 39 6.5.6 References 39 6.6
`
`6.8 ADSL SERVICE DELIVERY TO VDSL SERVICE DELIVERY
`6.8.1 Starting Network Scenario
`6.8.2 Target Network Scenario
`6.8.3 Drivers
`6.8.4 Options
`6.8.5 References
`
`6.9 NGDLC-Based ADSL to ONU-Based ADSLIVDSL
`6.9.1 Starting Network Scenario
`6.9.2 Target Network Scenario
`6.9.3 Drivers
`6.9.4 Options
`6.9.5 References
`
`BUSINESS SERVICES
`6.10 VDSL FOR RESIDENTIAL SERVICES TO VDSL FOR BUSINESS SERVICES
`6.10.1 Starting Network Scenario
`6.10.2 Target Network Scenario
`6.10.3 Drivers
`6.10.4 Options/lssues
`
`50 6.10.1 Starting Network Scenario 50 6.10.2 Target Network Scenario 50 6.10.3 Drivers 50 6.10.4 Optionshsues 50 6.11ADSL
`51 6.11.1 Starting Network Scenario 51 6.11.2 Target Network Scenario 51 6.11.3 Drivers 51 6.11.4 Options/hues 51 6.12 ADSL PLUS POTS
`END LINE POTS 6.12.1 Starting Network Scenario 6.12.2 Target Network Scenario 6.12.3 Drivers 6.12.4 Options & Issues 52 52 52 52 52 6.13 FTTN &
`VDSL 6.13.1 Starting Network Scenario 6.13.2 Target Network Scenario 6.13.3 Drivers 6.13.4 Option&sues 52 52 53 53 53
`
`FORRESIDENTIALSERVICES
`FORBUSINESSSERVICESTO
`6.11 ADSL FOR BUSINESS SERVICES TO ADSL FOR RESIDENTIAL SERVICES
`6.11.1 Starting Network Scenario
`6.11.2 Target Network Scenario
`6.11.3 Drivers
`6.11.4 Options/lssues
`
`PLUS
`TO
`6.12 ADSL PLUS POTS TO ADSL PLUS 2ND LINE POTS
`6.12.1 Starting Network Scenario
`6.12.2 Target Network Scenario
`6.12.3 Drivers
`6.12.4 Options & Issues
`
`SHORT RANGE
`TO
`LONG-RANGE
`6.13 FTTN & LONG-RANGE VDSL TO FTTK & SHORT RANGE VDSL
`6.13.1 Starting Network Scenario
`6.13.2 Target Network Scenario
`6.13.3 Drivers
`6.13.4 Options/lssues
`
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`“1P”ADSL
`“IP’ ADSL
`ADSL
`ADSL
`VDSL
`FTTK &
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`TO
`6.14 FTTNIFTTK & VDSL TO FTTH
`6.14.1 Starting Network Scenario
`6.14.2 Target Network Scenario
`6.14.3 Drivers
`6.14.4 OptionslIssues
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`NETWORK MIGRATION TECHNICAL REPORT Page 5 of 57 ADSLForum TR-004, Issue 1 5 10 15 6.14 FTTN/FTTK & VDSL
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`FTTH 54 6.14.1 Starting Network Scenario 54 6.14.2 Target Network Scenario 54 6.14.3 Drivers 54 6.14.4 Options/Issues 54 6.15 HDSL
`ACCESS 6.151 Starting Network Scenario 6.152 Target Network Scenario 6.15.3 Drivers and Issues 55 55 55 55 6.16 IDSL
`ACCESS 55 6.16.1 Starting Network Scenario 55 6.16.2 Target Network Scenario 56 6.16.3 Drivers and Issues 56
`
`FOR INTERNET
`TO
`FOR INTERNET
`6.15 HDSL FOR INTERNET ACCESS TO ADSL FOR INTERNET ACCESS
`6.15.1 Starting Network Scenario
`6.15.2 Target Network Scenario
`6.15.3 Drivers and Issues
`
`FOR INTERNET
`ACCESS TO
`FOR
`6.16 IDSL FOR INTERNET ACCESS TO ADSL FOR INTERNET ACCESS
`6.16.1 Starting Network Scenario
`6.16.2 Target Network Scenario
`6.16.3 Drivers and Issues
`
`7. ANNEX A : WORK SCHEDULE
`7. ANNEX A WORK SCHEDULE
`
`15
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`8. ANNEX B : CONTRIBUTING MEMBERS OF WORKING GROUP
`8. ANNEX B CONTRIBUTING MEMBERS OF WORKING GROUP
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`57
`57
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`9. DOCUMENT HISTORY
`9. DOCUMENT HISTORY
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`ACCESS
`ADSL
`INTERNET
`ADSL
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`NElWORK MIGRATION TECHNICAL REPORT
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`Page 6 of 57
`ADSLForum TR-004, Issue 1
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`1. STATEMENT OF PROJECT
`1. STATEMENT OF PROJECT
`
`The objective of this project is to capture ADSL network migration options for a set of defined initial and target
`It will also describe related technical
`network scenarios, identifying the key issues associated with each option.
`issues that may impact the deployment of an ADSL access network.
`
`The scope of the project is any access network migration scenarios that would involve use of ADSL or VDSL on a
`customers line in either the initial or target network scenarios. i.e. evolution to or from ADSL / VDSL.
`
`The primary focus is ADSL and VDSL technologies and architectures. However, to complete the picture of evolution
`scenarios, other xDSL technologies are not specifically excluded.
`
`The approach taken is that for each evolution situation, define it by :-
`
`• Starting network scenario
`
`• Target network scenario
`
`• Drivers (factors that will initiate and influence the migration)
`
`• Options (including advantages and disadvantages)
`
`Each evolution situation forms an individual SUb-section within this Network Migration Working Text.
`generic factors influencing migration to ADSL are also described.
`
`In addition
`
`TO ADSL
`INFLUENCING MIGRATION
`FACTORS
`2. FACTORS INFLUENCING MIGRATION TO ADSL
`
`This section seeks to list some of the major factors influencing the willingness, ability and speed of a telco or other
`service provider to migrate their access network to one that embraces the deployment and use of ADSL
`technology1. The influencing factors are categorised as being related to either network/architecture issues,
`equipment issues or business/service issues. Some of these may be regarded as critical success factors for ADSL.
`
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`5 10 15 20 25 30 NETWORK MIGRATION TECHNICAL REPORT Page 6 of 57 ADSLForum TR-004, Issue 1
`
`The objective of this project is to capture ADSL network migration options for a set of defined initial and target network scenarios, identifying the key issues associated with each option. lt will also describe related technical issues that may impact the deployment of an ADSL access network. The scope of the project is any access network migration scenarios that would involve use of ADSL or VDSL on a customers line in either the initial or target network scenarios. i.e. evolution to or from ADSL / VDSL. The primary focus is ADSL and VDSL technologies and architectures. However, to complete the picture of evolution scenarios, other xDSL technologies are not specifically excluded. The approach taken is that for each evolution situation, define it by :- Starting network scenario Target network scenario Drivers (factors that will initiate and influence the migration) Options (including advantages and disadvantages) Each evolution situation forms an individual sub-section within this Network Migration Working Text. In addition generic factors influencing migration to ADSL are also described. 2.
`(a) The presence of loading coils in some telco networks. This may have to be dealt with in the same way as they are for ISDN. (b) The degree to which Digital Loop Carrier (DLC) technology has been deployed to provision narrowband services, especially the older SLC96 and SLC5 systems. How is ADSL to be jumpered onto the final distribution copper? How will POTS from the SLC be “merged” with the ADSL signal via the splitter? Is the ADSL housed in an adjacent remote housing? (c) How will ADSL be housed and provided in next Generation DLCs (NGDLC)? (d) The remainder of the broadband network needs to be installed to exploit ADSL. E.g. ATM switches and backbone network or other broadband data overlay network, VoD servers etc. (e) There is no “plug and play” standard network solution available in a turn-key form yet. It requires extensive network design, integration and performance analysis skills. ’ Factors influencing migration FROM ADSL are described in sub-sections 6.8 & 6.9
`
`This section seeks to list some of the major factors influencing the willingness, ability and speed of a telco or other service provider to migrate their access network to one that embraces the deployment and use of ADSL technology’. The influencing factors are categorised as being related to either network/architecture issues, equipment issues or business/service issues. Some of these may be regarded as critical success factors for ADSL. 2.1
`
`NETWORK/ARCHITECTURE RELATED FACTORS
`2.1 NETWORK/ARCHITECTURE RELATED FACTORS
`
`(a) The presence of loading coils in some telco networks. This may have to be dealt with in the same way as they are
`for ISDN.
`
`(b) The degree to which Digital Loop Carrier (DLC) technology has been deployed to provision narrowband services,
`especially the older SLC96 and SLC5 systems. How is ADSL to be jumpered onto the final distribution copper?
`How will POTS from the SLC be "merged" with the ADSL signal via the splitter? Is the ADSL housed in an
`adjacent remote housing?
`
`(c) How will ADSL be housed and provided in next Generation DLCs (NGDLC)?
`
`(d) The remainder of the broadband network needs to be installed to exploit ADSL. E.g. ATM switches and
`backbone network or other broadband data overlay network, VoD servers etc.
`
`(e) There is no "plug and play" standard network solution available in a tum-key form yet. It requires extensive
`network design, integration and performance analysis skills.
`
`1 Factors influencing migration FROM ADSL are described in sub-sections 6.8 & 6.9
`
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`Page 7 of 57
`ADSLForum TR-004, Issue 1
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`(f) Solutions to the problem of dynamic IP address assignment and binding to physical network hardware addresses,
`particularly over ATM networks need to be solved, standardised (with one approach, not many) and widely
`supported.
`
`(g) Security concerns, especially with some of the earlier proposed router/Ethernet architectures need to be
`mitigated and the solutions disseminated.
`
`5
`
`(h) The integration of ADSL into the existing copper access network. Changes required to operational processes,
`test equipment and line-test procedures, network management systems2 and their databases. In addition, field
`personnel need to be trained to understand, install, operate and maintain this technology. Data equipment such
`as ATM or Ethernet/router interfaces will be new to many of them.
`
`10
`
`(i) Quantifying the impact on existing services (POTS band equipment on the same pair and spectral compatibility
`with other services on adjacent pairs) and removing any concerns.
`
`15
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`20
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`0) Concern on how to navigate through all the existing transmission technology "barriers" to ADSL that are in
`today's network e.g. ISDN, pair-gain systems, fibre systems. Also, concern about what barrier ADSL may be to
`future technologies such as FTTN or FTTK with VDSL, particularly if the telco has made a public commitment to
`VDSL or entered into a longer term contract. Will they have to fork-lift any ADSL deployed today to make way for
`the VDSL deployment committed to for tomorrow?
`
`(k) Satisfactory solutions to the home-wiring topology and installation and process. Can the customer self-install the
`ADSL remote unit? If so under what circumstances? What POTS splitter locations are convenient, work well,
`facilitate fault demarcation and look OK from the customer's perspective? Is an active or passive NT approach
`best?
`
`(I) Satisfactory solutions (equipment and process) to identifying the bit-rate that can be supplied (if at all) to an
`individual customer. What is the process from the point of sale (e.g. Can I have 2 Mbit/s VoD service?) to service
`provisioning with a high degree of confidence and minimal failures.
`
`(m) The ability of DSL products to ''fif' existing ISP network architectures in terms of existing router interfaces, impact
`on firewall, mUlti-cast, authentication capabilities, tools/methodology for Radius database updates etc.)
`
`25
`
`NETWORK MIGRATION TECHNICAL REPORT Page 7 of 57 ADSLForum TR-004, Issue 1 5 10 15 20 25 30 35 (f) Solutions to the problem of dynamic IP address assignment and binding to physical network hardware addresses, particularly over ATM networks need to be solved, standardised (with one approach, not many) and widely supported. (g) Security concerns, especially with some of the earlier proposed router/Ethernet architectures need to be mitigated and the solutions disseminated. (h) The integration of ADSL into the existing copper access network. Changes required to operational processes, test equipment and line-test procedures, network management systems’ and their databases. In addition, field personnel need to be trained to understand, install, operate and maintain this technology. Data equipment such as ATM or Ethernet/router interfaces will be new to many of them. 0) Quantifying the impact on existing services (POTS band equipment on the same pair and spectral compatibility with other services on adjacent pairs) and removing any concerns. Concern on how to navigate through all the existing transmission technology “barriers” to ADSL that are in today’s network e.g. ISDN, pair-gain systems, fibre systems. Also, concern about what barrier ADSL may be to future technologies such as FlTN or FITK with VDSL, particularly if the telco has made a public commitment to VDSL or entered into a longer term contract. Will they have to fork-lift any ADSL deployed today to make way for the VDSL deployment committed to for tomorrow? (k) Satisfactory solutions to the home-wiring topology and installation and process. Can the customer self-install the ADSL remote unit? If so under what circumstances? What POTS splitter locations are convenient, work well, facilitate fault demarcation and look OK from the customer’s perspective? Is an active or passive NT approach best? (1) Satisfactory solutions (equipment and process) to identifying the bit-rate that can be supplied (if at all) to an individual customer. What is the process from the point of sale (e.g. Can I have 2 Mbit/s VoD service?) to service provisioning with a high degree of confidence and minimal failures. (m) The ability of DSL products to “fit” existing ISP network architectures in terms of existing router interfaces, impact on firewall, multi-cast, authentication capabilities, tools/methodology for Radius database updates etc.) 2.2
`
`(a) Cost of equipment. When will it reach its floor and what will this be? Questions over port density (number of customers per line card, related to power consumption) and rack density/over booking levels. The common equipment costs at start-up represent exposed capital expenditure until there is a high service take up and hence equipment utilisation. (b) Spectral compatibility of ADSL equipment with other DSL technologies, especially in the unbundled “dark copper” regulatory regimes affecting some networks. (c) Physical space, power and cooling requirements in the CO. Linked to rack density issues in (a). A particular concern for ISPs/CLECs seeking co-location in ILEC Cos. These factors will also be very important to externally sited ADSL electronics for example when embedded in a next generation DLC. (d) Physical size and design aesthetics of the remote ADSL customer unit including the POTS splitter. (e) The best choice of physical interface on the remote ADSL customer unit e.g. Ethernet, ATM25, two ATM25, one ATM25 plus one Ethernet, Universal Serial Bus (USB), RS422 etc. 2 The contribution “Management of ADSL-Based Access Network” ADSLForum97-109 by Tsu-Kai Lu et al describes the evolution issues associated with ADSL network management.
`
`EQUIPMENT RELATED FACTORS
`2.2 EQUIPMENT RELATED FACTORS
`
`30
`
`35
`
`(a) Cost of equipment. When will it reach its floor and what will this be? Questions over port density (number of
`customers per line card, related to power consumption) and rack density/over booking levels. The common
`equipment costs at start-up represent exposed capital expenditure until there is a high service take up and hence
`equipment utilisation.
`
`(b) Spectral compatibility of ADSL equipment with other DSL technologies, especially in the unbundled "dark
`copper" regulatory regimes affecting some networks.
`
`(c) Physical space, power and cooling requirements in the CO. Unked to rack density issues in (a). A particular
`concern for ISPS/CLECs seeking co-location in ILEC Cos. These factors will also be very important to externally
`sited ADSL electronics for example when embedded in a next generation DLC.
`
`(d) Physical size and design aesthetics of the remote ADSL customer unit including the POTS splitter.
`
`(e) The best choice of physical interface on the remote ADSL customer unit e.g. Ethernet, ATM25, two ATM25, one
`ATM25 plus one Ethernet, Universal Serial Bus (USB), RS422 etc.
`
`2 The contribution "Management of ADSL-Based Access Network" ADSLForum97-109 by Tsu-Kai Lu et al describes
`the evolution issues associated with ADSL network management.
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`Page 8 of 57
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`(f) The capability and current status of operational support systems for ADSL (element managers etc.)
`
`(g) The availability, cost effectiveness and ease of use of appropriate test equipment for commissioning ADSL
`installations (e.g. line qualification testing, field deployable ATM testers for DSLAM commissioning etc.)
`
`(h) The status of equipment standards (approved and de-facto) for ADSL (line code, ATM via dual latency), ATM
`signalling and IP over ATM (inc. LANE, MPOA etc.) and subsequent impact on interoperability. Availability of
`equipment implementing these standards such as software application driven SVC set-up.
`
`5
`
`(i) Lack of turn-key end to end network equipment from ATM switch to CPE with inherent protocol stacks and plug &
`play software applications.
`
`BUSINESS/SERVICE RELATED FACTORS
`2.3 BUSINESS/SERVICE RELATED FACTORS
`
`(a) Need for a well defined strategy and service proposition backed by a viable business case with acceptable levels
`of risk (to both technology and market).
`
`(b) Forced to deploy ADSL in response to competition (by for example cable modems) when the telco business
`proposition isn't fully ready yet.
`
`(c) Lack of confidence in the broadband market and concem over maturity of broadband technology inhibits some
`telcos from committing to large volume procurements in the near term. This holds equipment prices high which
`doesn't help the telco business case unless a supplier is prepared to drop margins and carry all the risk with a loss(cid:173)
`leader.
`
`(d) The process for identifying customers in range of constant bit-rate (CBR) services such as VoD to be delivered
`over ADSL isn't accurate or cost-effective enough. This impacts on the marketing method for such services and
`the process for deciding on when/where the point of sale occurs.
`
`NETWORK MIGRATION TECHNICAL REPORT Page 0 of 57 ADSLForum TR-004, Issue 1 5 (h) The status of equipment standards (approved and de-facto) for ADSL (line code, ATM via dual latency), ATM signalling and IP over ATM (inc. LANE, MPOA etc.) and subsequent impact on interoperability. Availability of equipment implementing these standards such as software application driven SVC set-up. (i) Lack of turn-key end to end network equipment from ATM switch to CPE with inherent protocol stacks and plug & play software applications. 10 2.3
`(a) Need for a well defined strategy and service proposition backed by a viable business case with acceptable levels of risk (to both technology and market). (b) Forced to deploy ADSL in response to competition (by for example cable modems) when the telco business proposition isn’t fully ready yet. 15 (c) Lack of confidence in the broadband market and concern over maturity of broadband technology inhibits some telcos from committing to large volume procurements in the near term. This holds equipment prices high which doesn’t help the telco business case unless a supplier is prepared to drop margins and carry all the risk with a loss- leader. 20 (d) The process for identifying customers in range of constant bit-rate (CBR) services such as VoD to be delivered over ADSL isn’t accurate or cost-effective enough. This impacts on the marketing method for such services and the process for deciding on when/where the point of sale occurs. (e) The impact of regulations on service packaging, unbundling, cross-subsidisation and accounting separation limit 25 the degrees of freedom of some telcos e.g. are they allowed to deliver broadcast services over ADSL as has been trialled in France and Australia? Do they have to ensure spectral compatibility with other service providers exploiting dark-copper or does the incumbent telco have full control over all ADSL installed on their network? (0 3. Concern over the impact of ADSL on existing product lines such as ISDN and Tl or El private circuits. When is the broadband ADSL market mature enough to risk eating into these revenue streams?
`
`AND PASSIVE NT ISSUES 30 35 40 The regulatory view of who owns the remote ADSL unit together with the exact physical manifestation of the end- point of the telco network can affect the preferred ADSL remote unit form-factor. This in turn can have a profound impact on migration to and beyond ADSL-based networks. In some telco networks (such as in the USA) the regulatory regime dictates that the remote ADSL unit at the customer end of the line is Customer Premises Equipment (CPE) owned by the customer. Hence the network termination (NT) presented to the customer is a “wires-only” interface and is sometimes termed “passive”. In other networks such as in many European countries, the ADSL remote unit is itself considered part of the access network. Hence the NT interface presented to the customer is the ADSL customer interface connection (e.g. 10baseT Ethernet, ATM 25 etc.). In this latter scenario, the NT contains the ADSL electronics and is hence termed “active”. Hybrid architectures where the POTS splitter is separated from the ADSL remote unit are possible and some of these splitters may themselves be active requiring back-powering from the ADSL remote unit. However, the basic definitions of active/passive NT and the relative merits are broadly the same. (f) The capability and current status of operational support systems for ADSL (element managers etc.) (g) The availability, cost effectiveness and ease of use of appropriate test equipment for commissioning ADSL installations (e.g. line qualification testing, field deployable ATM testers for DSLAM commissioning etc.)
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`(e) The impact of regulations on service packaging, unbundling, cross-subsidisation and accounting separation limit
`the degrees of freedom of some telcos e.g. are they allowed to deliver broadcast services over ADSL as has
`been trialled in France and Australia? Do they have to ensure spectral compatibility with other service providers
`exploiting dark-copper or does the incumbent telco have full control over all ADSL installed on their network?
`
`(f) Concem over the impact of ADSL on existing product lines such as ISDN and T1 or E1 private circuits. When is
`the broadband ADSL market mature enough to risk eating into these revenue streams?
`
`ACTIVE
`3. ACTIVE AND PASSIVE NT ISSUES
`
`The regulatory view of who owns the remote ADSL unit together with the exact physical manifestation of the end(cid:173)
`point of the telco network can affect the preferred ADSL remote unit form-factor. This in tum can have a profound
`impact on migration to and beyond ADSL-based networks. In some telco networks (such as in the USA) the
`regulatory regime dictates that the remote ADSL unit at the customer end of the line is Customer Premises
`Equipment (CPE) owned by the customer. Hence the network termination (NT) presented to the customer is a
`''wires-only" interface and is sometimes termed "passive". In other networks such as in many European
`countries, the ADSL remote unit is itself considered part of the access network. Hence the NT interface
`presented to the customer is the ADSL customer interface connection (e.g. 10baseT Ethernet, ATM 25 etc.). In
`this latter scenario, the NT contains the ADSL electronics and is hence termed "active". Hybrid architectures
`where the POTS splitter is separated from the ADSL remote unit are possible and some of these splitters may
`themselves be active requiring back-powering from the ADSL remote unit. However, the basic definitions of
`active/passive NT and the relative merits are broadly the same.
`
`

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`NElWORK MIGRATION TECHNICAL REPORT
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`Page 9 of 57
`ADSLForum TR-004, Issue 1
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`1 0
`
`This section presents a list of the advantages often cited for each approach. To keep it simple it compares a stand
`alone active NT ADSL remote unit with a passive NT where the ADSL is emb