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Final report for Ofcom

Telecoms infrastructure access –

sample survey of duct access

3 March 2009

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Contents

1 Executive summary 1

1.1 Context and scope 1

1.2 Results 2

1.3 Analysis and key findings 4

2 Introduction 6

3 Survey scope and methodology 7

3.1 Scope of the survey 7

3.2 Sample selection methodology 9

3.3 Surveys 13

4 Operational issues and success factors 16

4.1 Introduction 16

4.2 Operational issues 16

4.3 Survey success factors 17

4.4 Overall success factors 18

4.5 Key considerations following operational lessons learned 19

5 Interpreting the results 21

5.1 Survey accuracy 21

5.2 Duct continuity 21

5.3 Cable cross-over 22

5.4 Duct accessibility in high usage chambers 22

5.5 Maintenance ducts 23

5.6 Copper recovery 23

6 Survey duct availability results 24

6.1 Introduction 24

6.2 Duct-end analysis 24

6.3 Route continuity analysis 31

7 Analysis and conclusions 36

7.1 Analysis of results 36

7.2 Key findings, next steps and conclusions 38

Annex A: Summary of Type 1 routes Annex B: Summary of Type 2 routes Annex C: Summary of Type 3 routes Annex D: Duct availability scenario Annex E: Route continuity plots

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Confidentiality Notice: This document and the information contained herein are strictly private and confidential, and are solely for the use of Ofcom.

We would like to acknowledge the support of Openreach throughout this project, without which it would not have been possible to have produced this report.

Copyright © 2009. The information contained herein is the property of Analysys Mason Limited and is provided on condition that it will not be reproduced, copied, lent or disclosed, directly or indirectly, nor used for any purpose other than that for which it was specifically furnished.

Analysys Mason Limited Bush House, North West Wing Aldwych London WC2B 4PJ UK Tel: +44 (0)20 7395 9000 Fax: +44 (0)20 7395 9001 enquiries@analysysmason.com www.analysysmason.com

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1 Executive summary

Analysys Mason, Setec Telecom and Lythgoes Limited are pleased to present Ofcom with this report, which forms part of Ofcom’s assessment of next-generation access infrastructure.

1.1 Context and scope

1 As part of the review of next-generation access (NGA), Ofcom is considering how infrastructure competition might be maintained in an FTTx world. The civil work required to deploy NGA infrastructure is a significant part of the business case of any NGA deployment, and some estimates put it as high as 80%1 of the overall cost. Although it is not the only remedy, providing

access to existing ducts, and therefore reducing the cost of deploying fibre for Communication Providers (CPs), is one solution that may lower the barriers to entry for CPs, and therefore support competition. In this context, this report provides the results of the sample infrastructure survey that was commissioned by Ofcom in the UK. The main objective of the survey was to make an indicative assessment of Openreach’s network for the level of occupancy in its telecoms duct infrastructure, and to help determine whether or not this offers a viable option for CPs to deploy new fibre cables in access and backhaul networks.

2 The main principle of the survey was based on contiguous routes to assess the availability and accessibility of the duct infrastructure. For this sample survey, 11 different UK cities/towns were selected to represent the diversity of Openreach’s national infrastructure network. Overall, 31 routes were surveyed, including 817 chambers, 18 206 duct-ends, and 76 street cabinets over a total route distance of 143km. In terms of the number of duct-ends involved, this constitutes the largest sample survey ever carried out and publicly made available in Europe. However, it should be noted that the sample considered only represents 0.02% of the total number of chambers in Openreach’s infrastructure network (4.2 million chambers overall), and, hence, is only indicative of the Openreach network. Different types of sample route, spanning different sections of the Openreach network, were selected according to a rigorous methodology, taking into account geotypes and other criteria (see main report) to be as representative as possible of the national infrastructure network. For each chamber on each selected route, a number of characteristics were recorded, including the number of duct-ends per chamber, and the unoccupied space within each duct-end; a duct-end being the aperture where a duct enters or leaves a chamber. The three types of route considered were:

Type 1 – contiguous route between a metro node and a local exchange • Type 2 – contiguous route between a local exchange and a street cabinet • Type 3 – contiguous route between a metro node and a street cabinet.

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3 The definition of space is key to this report. We differentiate between unoccupied space, available space and useable space, as specified below. During the survey, we used a 25mm tube as the basic unit of for assessing space in each duct.

Unoccupied space is defined as the space that is not occupied by existing cables.

Available space accounts for the fact that unoccupied space may not be available, due to the planning requirements from Openreach (spare capacity), or due to the obstruction of other cables in the duct nest.

Useable space relates to how the available space can be used, considering cable sizes, relative cable layout, installation methods, and infrastructure deployment engineering rules.

1.2 Results

4 The data set surveyed supports the analysis of two different types of result: the overall duct-end statistics and the route continuity statistics. The duct-end statistics involve all chambers surveyed along Type 1 and Type 2 routes, and these form the main part of the survey; the route continuity statistics considered 14 Type 3 end-to-end routes, to assess the capacity of the duct-ends along these routes if deploying new fibre. The duct-end statistics relates to all duct-ends present in each chamber surveyed whereas the route continuity statistics relates only to the two walls of the chamber that contain the duct ends that are along the surveyed route.

1.2.1 Duct-end statistics

5 The duct-end statistics, segregated into Type 1 and Type 2 routes, illustrate a high variability, depending on the section of the network surveyed. Figure 1 provides a high-level summary of our results. Type 3 route statistics do not appear in Figure 1 because they only relate to the continuity analysis.

Parameter Metro node to

exchange surveys (Type 1 routes) Exchange to cabinet surveys (Type 2 routes) Overall

Average no. of duct-ends per chamber

29.3 10.8 26.0

Average % of empty duct-ends

28% 17% 26%

Average unoccupied space per duct-end

36% 30% 35%

Figure 1: Main survey results [Source: Analysys Mason]

6 The average number of duct-ends per chamber increases with proximity to the metro node. This is in line with our expectation, as metro nodes are critical network nodes that connect access and core network of BT’s infrastructure for all voice and data traffic.

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7 The last two rows presented in Figure 1, namely Average percentage of empty duct-ends and

Average unoccupied space per duct are key, as they provide an estimate of the unoccupied space in the existing infrastructure. It can be seen that the level of occupancy is highly dependent on the section of the network surveyed, but that overall there is significant unoccupied space in the ducts surveyed.

8 The results also show that the availability of space varies from city/town to city/town. For example, Cardiff has significantly more unoccupied space than the average city/town surveyed in this project, and Stepney and Peterborough have significantly less unoccupied space than the average city/town surveyed.

9 The assessment of unoccupied space showed that:

Just over half of duct ends (51%) have unoccupied space for at least three 25mm tubes to

be inserted (three 25mm tubes approximates to 42% unoccupied space within the duct-end). • 26% of duct-ends are empty (100% unoccupied space)

• 22% of duct-ends are full (0% unoccupied space)

• for the 52% of duct-ends that are neither full nor empty, the potential use of the unoccupied space would depend on duct access policies, and the proposed methodology of the potential new cable installation

• 78% of duct-ends have at least 14% of unoccupied space (14% equates to one 25mm sub-duct inserted in the duct).

1.2.2 Route continuity statistics

10 The route analysis considered 14 routes extending to street cabinets, covering a range of different cities/towns and geotypes. The route analysis helps to assess, by visual inspection, where different levels of space availability could occur if access to the ducts were to be provided along these routes. The analysis was based on a red, amber, green (RAG) scale, representing the likelihood of finding useable space. The RAG concept is defined below:

green – two or more empty duct-ends in a chamber wall on the route.

amber – one empty duct-end and one duct-end that can accommodate three or more sub-ducts, or three or more duct-ends that can accommodate three or more sub-ducts

red – all situations not covered by amber and green

11 Of all the 14 routes analysed, 36.4% of the sections were red, 17.1% were amber, and 46.4% were green. Also, all routes analysed had at least one red section in the last 10% of the route (final sections to the street cabinet).

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1.3 Analysis and key findings

12 Overall, significant unoccupied space in the duct infrastructure was found: the overall average space in the duct-ends was 35%. Also, the results show that 51% of all duct-ends surveyed have at least 42% of unoccupied space. We also found that the distribution of the unoccupied space varies according to the cities/towns and sections of the Openreach network considered: more space is unoccupied in sections near the metro node, and less space is unoccupied in sections near the street cabinet. If there is demand for fibre to the cabinet (FTTC) deployment, the duct space between the cabinet and exchange would be of most interest to CPs, as they would have to use that section to connect to the copper access network (starting from the cabinet).

13 It should be noted that the result and interpretation of this analysis will vary depending on the technology used to provide duct access (smaller diameter sub-ducts, mini-ducts, micro-ducts) as improvements in technology will optimise the use of the available space. The engineering rules that would have to be developed to provide duct access would also significantly influence the way space would be utilised within the ducts.

14 During the survey, it was also noted that available space at the duct-end would not always directly translate into useable space for a CP willing to use the ducts, because:

• a duct might have collapsed somewhere in the section

• the cable arrangement far into the duct may be such that existing cables cross over, and may prevent any further cables being inserted in the duct

• engineering rules may prevent unoccupied space being used (e.g. to limit disruption with other cables in the duct).

15 Our sample survey shows that the occupancy of ducts is highly variable depending on the section of the network considered, and on the types of city/town. Based on the indicative sample we studied, ducts between the metro node and local exchanges (backhaul network) are generally less occupied than ducts between exchanges and street cabinets (access network). This implies that there would be a greater probability of CPs being able to install their own fibre in existing ducts in the backhaul network.

16 In the access network, duct-ends are more likely to be congested in some sections of the route, highlighting the fact that there may be a requirement for CPs to use alternative options and/or methodologies to install their cables in the congested sections. While duct access may still be a viable option in the access network, it may need to be complemented by extra civil work to increase infrastructure capacity, the use of dark fibre (where available) or the use of conduits of alternative infrastructure providers.

17 A number of operational difficulties were encountered during the surveys, which would also be applicable to duct access roll-out. We have identified a number of measures that can be used to mitigate these difficulties. For example, we identified that walk-over surveys, prior to commencing full surveys, would significantly improve the efficiency of the overall surveying process. We also found that a close collaboration with local authorities was key in improving the

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efficiency of the planning of the surveys to avoid areas that are shut off during special events, and to facilitate surveys in traffic-sensitive areas. In most cases, operational issues can be mitigated during duct access roll-out by robust processes, sound engineering rules and co-operative planning.

18 Based on the operational experience gained during the sample surveys, we believe it would be prudent for any potential CP who is planning to make use of ducts from an infrastructure provider to first carry out a small number of sample surveys to gauge the accuracy of the infrastructure provider’s plans for each area. Whilst this would require some initial investment, it would help improve the accuracy of implementation planning and costing.

19 Empty ducts would be more desirable from the CP’s perspective, as they would be operationally easier to implement, maintain and manage. However, occupied ducts would inevitably have to be utilised if deployment increased. Practical, workable agreements to allow access to occupied ducts between Openreach and the Communications Provider would have to be addressed.

20 Based on the key learnings of our survey, we identified a number of key actions that would be required to implement a duct access offer, if it was to become available. These include:

• Development of engineering rules to dictate how unoccupied space may be used by a CP • Development of a duct access framework, providing key end-to-end processes involved in a

duct access product

• Development of a governance model for CPs with a single point of contact in a potential multi-infrastructure provider environment

• Development of a framework to monitor deployment Key Performance Indicators (KPIs) • Development of training programmes for field forces to ensure they are properly qualified for

all tasks involved in duct access

• Development of a reference database containing up to date digitised network plans and duct records useable by both infrastructure providers and CPs

• Extension of this survey to other Telecommunication Providers and Utilities infrastructure to encourage competition and provide more options for a CP to deploy their NGA network, especially in congested sections of the infrastructure network (i.e. access network).

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2 Introduction

21 Next-generation access (NGA) networks, as discussed in Ofcom’s September 2007 Consultation on Future Broadband2

, offer opportunities for new services and business models due to the potential ability to provide higher bandwidth and higher quality services. The move to NGA networks is one of the most fundamental changes in telecommunications infrastructure since the introduction of market competition.

22 Although the cost of bandwidth in the active layer has reduced significantly over the years, and continues to reduce, the cost of the civil works – such as digging and trenching – represents a major barrier for operators to deploy NGA infrastructure. Previous studies show that the civil work can account for up to 80%3

of the total cost of the infrastructure to be deployed.

23 It is in this context that Ofcom is looking at open duct access to support future infrastructure-based competition in access and backhaul.

24 Ofcom’s survey of international best practice in infrastructure access, summarised as part of the new build consultation, suggested infrastructure access is more feasible than previously thought.4

In Europe, two major incumbents (Portugal Telecom Communicacoes and France Telecom) are already offering duct access as a regulated product. Also, in an effort to try and harmonise infrastructure access policies throughout the European Union (EU), the EU Commission is currently preparing a recommendation on regulated access to NGA networks, which is expected to be published this year.

25 Ofcom is aware of the challenges involved in determining whether duct access can, and should be, provided, and what a successful duct access offer might look like for alternative service providers, including those that have little physical infrastructure, for example, new entrants. It believes that an appropriate first step to determine appropriate regulatory policy concerning NGA is to form an initial, indicative view as to the availability and accessibility of suitable telecoms infrastructure in the UK. This follows the example of the French regulator, ARCEP, which conducted a similar sample survey in 2007.

26 In this context, Ofcom engaged Analysys Mason Limited (‘Analysys Mason’) and its partners, Setec Telecom and Lythgoes Limited, to undertake a sample survey of the duct infrastructure of Openreach, to help Ofcom make an informed decisions about NGA regulatory policy. This report provides the results of the survey, along with Analysys Mason’s views of what it would take to implement duct access in practice. It should be noted that other CPs and other utilities may have duct infrastructure which may be appropriate for NGA, but this project focused exclusively on Openreach’s infrastructure. 27 The main objective of the survey was to assess Openreach’s infrastructure network to gain an insight into the potentially available telecoms duct infrastructure, and to determine whether or not it offers a viable option for CPs to deploy new fibre cable in Openreach’s access and backhaul networks.

2

http://www.ofcom.org.uk/consult/condocs/nga/future_broadband_nga.pdf

3

The costs of deploying fibre-based next-generation broadband infrastructure, Analysys Mason for the Broadband Stakeholder Group, September 2008.

4

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3 Survey scope and methodology

3.1 Scope of the survey

3.1.1 Survey structure

28 The samples selected for this survey were based on routes spanning different sections of Openreach’s infrastructure, to assess the continuity of duct access from a ‘starting’ network node to an ‘end’ network node. As illustrated in Figure 2, network nodes included in the survey are of the three main types outlined below.

Metro nodes – network nodes connecting Openreach’s access and core networks, and generally used by Openreach as a handover point to connect to CPs.

Local exchanges – network nodes defining the termination of the copper access network for current generation access networks. In Openreach’s network, two types of local exchange exist: Tier 1 and Tier 2 exchange. Tier 1 exchanges are usually directly attached to one or several metro nodes and Tier 2 exchanges are usually attached to Tier 1 exchanges.

Street cabinets – network nodes providing direct or indirect interconnection between the access network and the customer premises. In NGAs, the role of street cabinets is crucial, as they would provide the termination of the copper network for fibre-to-the-cabinet (FTTC) deployments, significantly shortening the copper local loop (referred to as the sub-loop). 29 In this survey, three types of route were considered to be representative of the different sections of

Openreach’s infrastructure network, as illustrated in Figure 2:

Type 1 – contiguous route between a metro node and a local exchange • Type 2 – contiguous route between a local exchange and a street cabinet

Type 3 – contiguous route between a metro node and a street cabinet – a Type 3 route can be either a combination of Type 1 and Type 2 routes, or a route to a street cabinet located between a metro node and an exchange.

30 From an operations perspective, a route is defined as a series of chamber-to-chamber duct sections that extend between two network nodes. As illustrated in Figure 2, a chamber can be either a manhole or a box. A box is usually defined as a structure with a floor area equal to, and directly below, its opening, and with a volume governed by the depth. In contrast, a manhole is defined as an underground structure with a volume that need not be limited, and usually having one standard opening and a ceiling.

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Intermediate street cabinet Manholes (145k total) Boxes (4.2m total) Customer premises

Chamber Network node Duct Link

(90,000 total) Scope of survey Type 1 Route Metro node (106 total) Exchange (5592 total) ‘Last’ street cabinet Type 2 Route Intermediate street cabinet Type 3 Route Intermediate street cabinet Manholes (145k total) Boxes (4.2m total) Customer premises Chamber

Chamber Network nodeNetwork node Duct LinkDuct Link

(90,000 total) Scope of survey Type 1 Route Metro node (106 total) Exchange (5592 total) ‘Last’ street cabinet Type 2 Route Intermediate street cabinet Type 3 Route

Figure 2: Survey scope [Source: Analysys Mason]

3.1.2 Survey range

31 For this sample survey, 11 different UK cities/towns were considered to be typical examples of Openreach’s national infrastructure network (see Section 3.2 for the selection process). Overall,

817 chambers, 18 206 duct-ends and over 143km of route were surveyed. Figure 3 provides a summary of the range of the survey that was conducted.

Scope Comments

11 cities/towns Birmingham, Cardiff, Crawley, Croydon, Glasgow,

Leeds, Manchester, Milton Keynes, Peterborough, Southampton and London (Stepney)

817 surveyed chambers:

• 510 chambers surveyed on Type 1 routes

• 307 chambers surveyed on Type 2 routes

The breakdown of chamber types was as follows (manhole/boxes):

• 293/217 for Type 1 routes • 25/282 for Type 2 routes 22 exchanges passed,including:

• 17 Tier 1 exchanges • 5 Tier 2 exchanges

The actual exchanges were not surveyed, but the chambers connecting them to the infrastructure network were included in the survey

31 surveyed routes, including:

• 22 Type 1 routes

• 9 Type 2 routes

In total, 14 Type 3 routes starting in metro nodes and terminating on a street cabinet were surveyed. The detail of these routes can be found in Annex C.

18 206 surveyed duct-ends:

• 14 956 duct-end surveyed on Type 1 routes • 3250 duct-end surveyed on Type 2 routes

The survey considered duct-ends in each surveyed chamber

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32 A breakdown of the surveys by city/town is provided in Figure 4. It should be noted that Type 2 route surveys were only conducted in five of the 11 surveyed cities/towns, which explains why there is a larger sample in these cities/towns.

City/town No. of manholes No. of boxes No. of chambers (manholes and boxes) No. of duct-ends No. of street cabinets Birmingham 20 6 26 1286 1 Cardiff 45 77 122 2468 17 Crawley 1 32 33 344 5 Croydon 51 79 130 2853 11 Glasgow 48 82 130 2894 18 Leeds 26 36 62 1959 5 Manchester 18 44 62 1812 7 Milton Keynes 20 77 97 1641 12 Peterborough 40 55 95 1035 0 Southampton 38 11 49 1001 0 Stepney 11 0 11 606 0 Total 318 499 817 18 206 76 Figure 4: Survey sample by city/town [Source: Analysys Mason]

3.2 Sample selection methodology

3.2.1 Introduction

33 The selection of the sample to be surveyed was important, since it had to be indicative of the national Openreach infrastructure network to form a balanced view of the availability and accessibility of the infrastructure throughout the UK. In this section, we explain in detail the selection methodology and criteria that were used to derive the optimum sample, incorporating the following:

• selection criteria for cities/towns to be surveyed

• selection methodology for Type 1, Type 2 and Type 3 routes (as defined in Section 3.1.1). 34 The overall sample selection process is highlighted in Figure 5.

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Selection of a single Metro Node per city/town

Identification of 2 Local Exchanges(LE) linked to the Metro Node per town

Selection of one or several Street Cabinets and selection of Type 2 routes Selection of Type 1 routes and chambers

between Metro Node and LE

BT duct plans (Ordnance Survey maps)

Street cabinet list and pressure line diagrams (502 maps) Selection of cities and towns

Geotype and Exchange Type BT/OFCOM collaboration Input in decision process

Selection of a single Metro Node per city/town

Identification of 2 Local Exchanges(LE) linked to the Metro Node per town

Selection of one or several Street Cabinets and selection of Type 2 routes Selection of Type 1 routes and chambers

between Metro Node and LE

BT duct plans (Ordnance Survey maps)

Street cabinet list and pressure line diagrams (502 maps) Selection of cities and towns

Geotype and Exchange Type BT/OFCOM collaboration Input in decision process Figure 5: High-level sample selection process [Source: Analysys Mason]

3.2.2 Selection of cities/towns

35 Eleven cities/towns were selected for this sample survey. The selection criteria for the cities/towns included:

• geographical spread throughout the UK to be representative of the 27 BT ‘districts’ • the age of Openreach’s infrastructure (new towns versus old towns)

• city/town characteristics (capital city, other major city, coastal city, etc.)

36 The selection criteria for each of the cities/towns selected is listed in Figure 6. It should be noted that this survey concentrated on urban areas, since NGA is expected to be deployed first in the most commercially attractive areas (i.e. areas of highest line density and hence revenue density).

Towns BT district Other selection criteria

Birmingham Central Midlands Second largest city in UK

Cardiff South Wales Capital of Wales

Crawley South Downs New sub-urban town

Pilot survey

Croydon London South New city within the M25 conurbation

Glasgow West Scotland Largest city in Scotland

Leeds Mid Yorkshire Third largest city in the UK, and legal

centre

Manchester Manchester Major commercial centre with

residential property

Milton Keynes South Midlands New town

Peterborough East Midlands New town

Southampton South Major port

Stepney (London) Central London Capital city

Figure 6: Cities/Towns selected [Source: Analysys Mason]

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3.2.3 Route selection process

37 As specified in the scope section of this document, three types of route were considered for this sample survey (Type 1, Type 2 and Type 3). The selection process for each type of route is provided in the sections below.

Type 1 routes – selection methodology

For each of the selected 11 cities/towns, a single metro node was chosen as the starting point of the Type 1 routes. For each metro node selected, two local exchanges were identified to define two routes. Local exchanges were identified to give a broad spread of examples within the following criteria to ensure the sample routes were reasonably representative:

• geotypes defined by Openreach (see Figure 7) • national distribution of local exchanges • type of exchange (i.e. Tier 1 or Tier 2).

38 Once the metro nodes and associated local exchanges were identified for each of the routes, Openreach provided duct plans and Ordnance Survey plans, where all chambers along the defined routes could be identified and marked in preparation for the survey. Where there was more than one route between metro node and the local exchange, a unique set of chambers defining that route was selected based on the distribution of manholes versus boxes on that route.

Type 2 routes – selection methodology

39 Type 2 routes span from a local exchange to a street cabinet. Type 2 routes were surveyed in five cities/towns, starting from the same exchanges that were identified during the Type 1 route selection process for the same five cities/towns. Street cabinets were identified by obtaining a ‘Street Cabinet List’ from Openreach for the exchange areas selected in the previous phase, and then obtaining ‘Pressure Line Diagrams (502)’ from Openreach for each of the cables from the exchange to the listed street cabinets. Pressure Line Diagrams are schematic diagrams that provide the layout of the cable pressure system, which is used in large copper cables to prevent water ingress. The Pressure Line Diagrams provide the total cable length from the exchange to the cabinet. Two cable routes from the exchange to a ‘target’ street cabinet were then selected, with each route passing a minimum of two additional street cabinets. For the selected routes, duct plans and Ordnance Survey plans were obtained from Openreach, followed by walkover surveys of the actual route.

Type 3 routes – selection methodology

40 Type 3 routes are a combination of Type 1 and Type 2 routes. Type 3 routes are either a concatenation of Type 1 and Type 2 routes (metro node to street cabinet route through one or several exchanges), or a sub-route of Type 1 routes (metro node to street cabinet located before an

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exchange route). The selection methodology for Type 3 routes was therefore dictated by the selection of Type 1 and Type 2 routes. Type 3 routes were exclusively used for the route continuity analysis (see Section 6.3).

3.2.4 Route sample summary

41 Annex A illustrates the 22 Type 1 routes that were selected for the survey, Annex B summarises the nine Type 2 routes and Annex C the 14 Type 3 routes.

Geotype Geotype definition Line density (lines per sq. km) % exchanges (national BT network) % household per geotype (national BT network) No. of exchanges in sample % exchanges in sample 1 Super-urban >13 431 0.5 0.8 3 13.6 2 Urban 1939–13 431 4.2 15.4 8 36.4 3 Sub-urban (5,000+ lines) 326–1938 15.5 52.4 7 31.8 4 Sub-urban (<5,000 lines) 326–1938 0.7 0.4 1 4.5 5 Rural (5,000+ lines) <326 8.5 14.0 1 4.5 6 Rural (<5,000 lines) <326 70.5 16.3 2 9.1

Figure 7: Sample exchange distribution [Source: Analysys Mason]

42 Figure 7 shows that the majority (82%) of sample exchanges selected for this survey are either in Super-urban, Urban or Sub-urban areas. This is consistent with areas where NGA is likely to be deployed first (i.e. areas of highest line density and, hence, revenue density). It also shows that we considered a range of geotypes to try to capture the different infrastructure characteristics of different areas.

43 It should also be noted that, although this is the largest sample survey in Europe of this type, it is very small when compared to the overall network, representing only 0.02% of the (up to) 4.2 million chambers of the infrastructure network. This sample provides an indicative view of the Openreach network.

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3.3 Surveys

3.3.1 Survey recorded data

44 For each surveyed chamber, on every route identified during the route selection process, the following data was recorded, using standard survey forms, as illustrated in Figure 8:

• location and type of chamber

• total number of duct-ends in the chamber

• existence of sub-ducts within each duct-end surveyed • diameter of duct-end

• number and diameter of cables in each duct-end surveyed

• unoccupied space in each duct-end surveyed, measured in multiples of 25mm sub-ducts (see Section 3.3.3 for details).

Chamber ID Lat. Long.

Chamber ducts 1 2 3

-CH-Adress (nearest building)

Potential additional number of 25 mm tubes into the duct Duct Diameter (mm) 50 76 90 No of existing cables More 2 3 4 0 1 20 Other Diameters D u c t N o . S u b -d u c te d Wall To chamber or 110 non surveyed object

Figure 8: Example survey form (used for each chamber) [Source: Setec Telecom]

3.3.2 Survey planning and execution with Openreach’s team

45 In Openreach’s network, the infrastructure is segregated into districts, where each regional team has the responsibility of deploying and maintaining the infrastructure in its own district. Since our survey, conducted by our partner Lythgoes Ltd, spanned 11 different BT districts, the detailed planning and execution of each set of surveys involved close liaison with the regional Openreach team responsible for each district surveyed. This stage of the project involved:

• communicating the selected survey routes to Openreach

• checking for any traffic sensitive areas (the responsibility of Openreach), or other local restrictions, and applying for any necessary work permits, and/or opening-up notices

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• allocating an Openreach survey support team to the Analysys Mason survey team • agreeing day-to-day meeting points, and programmes of work

• opening up of the chambers by Openreach, ready for the Analysys Mason survey team (this included removing manhole/box covers, testing for gas, pumping out of water, if necessary, and generally providing safe access

• closing of the chambers by Openreach after the Analysys Mason survey was completed.

3.3.3 Assessment of unoccupied duct space

46 In this report we differentiate between unoccupied space, available space and useable space, as specified below.

Unoccupied space is defined as the space that is not taken by existing cables.

Available space accounts for the fact that unoccupied space may not be available, due to the planning requirements from Openreach (spare capacity), or due to the obstruction of other cables in the duct nest.

Useable space relates to how the available space can be used, considering cable sizes, installation methods, and infrastructure deployment engineering rules.

47 Part of this study has been the examination of different methods of assessing unoccupied duct space. At the start of the project, the first set of surveys (Crawley) was executed as a pilot study, and unoccupied space was assessed on a subjective basis by simple visual inspection, e.g. the duct has approximately 25% free space. After the pilot study it was realised that a more objective and consistent method was required to record unoccupied space in the ducts. For this purpose, we used a 25mm tube as the basic unit of measuring unoccupied space. The selection of the size of the tube was based on two operational considerations:

• the vast majority of sub-ducts in Openreach’s network have a diameter of 25mm

• the size of the pulling rod required to pull a rope or a cable from one chamber to the next adjacent chamber is 25mm (smaller pulling rods are more flexible and tend to bend and jam in the middle of the ducts).

48 The use of a short length of tube was appropriate, as it made allowances for the way in which existing cables enter the duct, e.g. from below, resulting in the cable arcing towards the top of the duct, and thus reducing the space.

49 The 25mm tube methodology is not a definitive guide for measuring unoccupied space, but it offers a consistent, objective and practical approach. The diameter of the tube to be used would vary with new cable installation technologies, but offers a reasonable measure of today’s installation technique and sub-duct sizes currently used in Openreach’s network.

50 The vast majority (95%) of the Openreach surveyed ducting is 90mm in diameter. From a geometric perspective, a maximum of seven 25mm tubes (sub-ducts) can be inserted in a 90mm

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duct. Therefore, we assume that each tube that can be inserted in a duct represents 14.2% of unoccupied space in a 90mm duct. The unoccupied space, defined according to the number of 25mm tubes that can be inserted in a duct, is provided in Figure 9.

Number of 25mm tubes that be inserted in a 90mm duct unoccupied space (%) 0 0 1 14 2 28 3 42 4 56 5 70 6 84 7 100 Figure 9: Unoccupied space definition [Source: Analysys Mason]

51 Figure 10 provides illustrative examples of 90mm ducts with 28% of unoccupied space (i.e. two 25mm tubes can be inserted in addition to the existing cables). Other examples of duct occupancy are provided in Annex D.

90 mm duct Inserted 25mm tube Existing cable 90 mm duct Inserted 25mm tube Existing cable

Figure 10: 28% unoccupied space [Source: Analysys Mason]

52 Figure 10 also illustrates that our methodology dictates that the measured unoccupied space will always be less than the actual unoccupied space. This is consistent with the fact that, for practical reasons, the small areas of unoccupied space around existing cables are not available for use.

53 In the surveys, duct-ends that contained no cables (empty duct-ends) would have ‘zero’ recorded on the survey form in the ‘number of existing cables’ box (see Figure 8). However, not all empty ducts would be fully accessible to allow the maximum number of tubes to be inserted. For example, ducts at the bottom of a chamber could be obscured by cables above, or across, them, preventing tubes from being inserted.

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4 Operational issues and success factors

4.1 Introduction

54 The execution of this study has demonstrated that there is a wide range of operational issues and success factors involved in the field survey of underground duct networks. These issues are not only pertinent for CPs considering duct access products to deploy their own fibre network, but also for the infrastructure provider who has to install and maintain its duct network.

4.2 Operational issues

55 The survey teams encountered a number of operational issues while conducting the surveys, which are described in this section.

56 Climatic conditions – heavy rain during the survey period caused the need for extensive pumping of chambers, leading to significant delays, and programme disruption. In some cases, some chambers were completely flooded, making it impractical to drain the water out of them. The impact of this could be reduced by avoiding the need for field operations in wet weather, but, in reality, the availability of pumping teams and equipment is essential, as the presence of water in chambers is high in the UK.

57 Restrictions in traffic-sensitive areas – some chambers located in traffic-sensitive areas could not be accessed or surveyed, because Openreach could not obtain the necessary permissions from the authorities, given the restricted time windows offered by this project. This factor could be reduced by a longer project planning period, providing greater notice to the local authorities responsible for traffic control.

58 Special event restrictions placed by local authorities – some chambers could not be accessed or surveyed because they were located in areas restricted by the council due to special events, such as Christmas parking embargos, national conferences, religious festivals, and street parties, preventing access to whole areas of the network. Initial discussions with a local authority regarding any future planned restrictions would reduce the issue.

59 Health and safety issues (sewage) – in some cases, some chambers could not be accessed for health and safety reasons due to the presence of sewage. This was because the chambers had been completely flooded, and the sewage network had spilled into the telecoms infrastructure network. It is difficult to mitigate this risk, as it cannot be predicted.

60 Health and safety issues (deep manholes) – also, some chambers were very deep, requiring a surveyor to use scaffolding and/or wear a safety harness to gain access to the working area. These extra access restrictions cause time delays, and potential disruption to the programme. One approach to mitigate the issue would be to deploy a specialist survey team with additional access

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equipment to survey the deep manholes. This would carry significant cost, and may not be effective, especially if records identifying the deep manholes are not accurate.

61 Health and safety issues (residual gas) – in some cases, there was still a high level of residual gas in the chamber, causing the chamber to be an unsafe place of work, hence, these chambers were not surveyed. It is difficult to mitigate this issue as it cannot be predicted.

62 Accuracy of infrastructure drawings – some ofOpenreach’s drawings are no longer maintained, and, hence, depending upon the timing of the more recent infrastructure works, they may not be accurate. These inaccuracies can lead to time delays, programme disruption, and possibly inaccurate surveys. In one instance, a metro node located on the Openreach plan had been recently relocated to another Openreach premise. A walk-over survey to verify drawing accuracy before the main survey would prevent many of these issues.

63 Hazardous objects placed on the top of chambers – in some cases, scaffolding was built on the top of chambers, making the chambers inaccessible. In other cases, cars were parked over chambers. A walk-over survey could eliminate some of these issues by, for instance, identifying scaffoldings built over the target chambers to survey.

64 Overgrown vegetation – many chambers were overgrown, leading to time delays, and programme disruption. In some cases, it was not possible to remove the obstructions with the equipment available to the survey team. These issues could be overcome by a walk-over survey, and a programme of access works before the main surveys.

65 Chambers located in dense pedestrian areas – working in chambers under pavements at pedestrian crossings would have caused an unacceptable level of congestion, and a potential for injury to pedestrians, and, hence, these chambers were not surveyed. These issues could be overcome by a walk-over survey, and a programme of access works before the main surveys. 66 High cable density in chambers – in densely populated chambers, the survey of ducts and cables

can be challenging, and less accurate, due to the general congestion and complexity of cable and duct arrangements.

67 In summary, the field surveys demonstrated that it can be challenging to gain access to a selected part of a duct network, and that working conditions can make operations ineffective. However, it should be noted that, in real operations, access would be required to all relevant parts of the network. Also, the survey team was totally dependent on the Openreach field team to provide safe access into the chambers. It is critical that access teams are fully equipped with equipment suitable for the task, and that the equipment is well maintained to prevent breakdowns.

4.3 Survey success factors

68 Due to the operational constraints highlighted in Section 4.2, chambers identified on Openreach plans could not always be surveyed. We define the success rate as the proportion of chambers

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identified on the plan that could be surveyed. The success rate can be optimised by mitigating some of the operational risks identified in Section 4.2 by:

• gaining prior knowledge of major events that would lead to the closure of an entire area for surveys

• giving enough notice to the local authorities to survey chambers located in traffic-sensitive areas

• trying to avoid surveys during months that traditionally have the highest levels of rainfall to minimise the water that has to be pumped out of the chambers

• carrying out prior walk-over surveys to locate the chambers to be surveyed to a) reconcile chambers shown on the plans and chambers located in the street and b) estimate and mitigate the risks with surveying these chambers.

69 The success rate of the completion of the surveys over the duration of this study was 57%. This success rate was largely attributed to very poor climatic conditions during the survey period – the Met Office reported that the summer of 2008 was “one of the wettest on record across the UK.”5

. Many chambers required pumping, which often took a long time. The other main factor was accessibility of chambers located in traffic-sensitive areas, and the available timeframe of the survey did not provide sufficient prior notice to the local authorities for planning traffic management issues.

70 The success rate for manholes (42%) was significantly lower than that of boxes (74%). The reason for this difference was associated with the fact that manholes are significantly larger than boxes, and therefore it is not always possible to drain manholes in the provided time window. For instance, one manhole was pumped for around five hours, and there was still water pouring out of the ducts at a rate estimated by the survey team to be 200 litres per minute.

71 The introduction of walk-over surveys prior to the commencement of the phase 2 surveys (Type 2 routes) increased the success rate from 51% to 70%. This demonstrates that walk-over surveys provide effective mitigation against survey failure, as highlighted in paragraph 68.

72 The variability of success rate across different chamber types and survey phases indicates that any programme/costing for the roll-out of fibre in existing ducts should include a contingency for abortive field costs. However, in a real deployment scenario, a survey success rate of 100% would have to be achieved.

4.4 Overall success factors

73 Factors that have contributed to the overall successful execution of the study have been: • support and cooperation from Openreach throughout the work

• open communications with Ofcom and Openreach

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• good working relationships with the Openreach regional managers • operational knowledge of the extent and nature of the Openreach network

• access to Openreach data, e.g. metro node lists, exchange lists, and street cabinet lists • availability of Openreach network plans, and duct plans

• access to chambers provided by Openreach • safe working environment provided by Openreach.

The above factors illustrate the key role of the owner/operator of the existing infrastructure in any successful operations to be executed by a new cable owner/service provider within the existing infrastructure. If any of the factors had been negative, the study would have been considerably hampered, and, in fact, may not have been successfully completed. The development of any potential ‘Duct Offer’ would need the full co-operation of the existing infrastructure owner, i.e. Openreach.

4.5 Key considerations following operational lessons learned

74 From the operational issues and success factors above, we have summarised operational lessons learned that would be relevant to the roll-out of a future duct access project. These are key considerations in any fibre roll-out project, and are detailed below.

75 The extent of the existing duct network – the extent of the existing network will have a direct influence on the economic grounds for providing duct access, and the planning of any potential duct access project, as it will constrain where a network can be deployed without conducting civil works.

76 The nature of the existing duct network – ideally the existing duct network will have been developed in a planned manner, providing capacity for growth, and contiguous routes. The nature of the existing network would govern the feasibility of providing any new duct access, as spare capacity is further pre-requisite of not having to conduct civil works.

77 The condition of the existing duct network – if the existing network is poorly maintained there would be a direct impact upon the viability of expanded duct access. For example, if the existing duct chambers do not provide a safe working environment, or are liable to flooding, it is unlikely that duct sharing will be economically viable due to the cost of remedial works to fix the existing infrastructure.

78 Access to the existing duct network – if the existing network cannot be physically accessed in an efficient manner, there is little value in providing regulated access. For example, physical access would be required for survey, installation, testing, maintenance, repair, and upgrade.

79 Availability of network records – existing accurate records would significantly de-risk the roll-out of new access to existing ducts. The existing records would reduce the extent of survey required, speed up the out planning process, and improve the efficiency of new network roll-out by CPs.

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80 Access to duct-ends – the existing duct network will be of limited value if the duct-ends cannot be accessed. For example, the chambers would need to provide access to duct-ends at a workable height and location, and the duct-ends would need to be clear of crossing cables and other apparatus.

81 Useable duct space – useable duct space is key to the feasibility of the use of existing ducting. The extent of useable space depends upon the future space requirements of the existing cable company, and the space requirements of any new cable company. The nature, and space requirements, of the technology to be deployed is critical.

82 Scope for duct sharing – if there are no empty ducts, the alternative would be duct sharing, which consists of installing a new cable within a duct that is already occupied by some cables. While there are different technologies available for duct sharing, there is a higher level of risk of damage to existing cables, especially if these are old, fragile, and possibly already damaged.

83 Blocked ducts – it is inevitable that an existing duct network will contain blocked, and/or collapsed ducts, yet it is difficult to assess the extent of the issue without inspection. End-to-end surveying of all proposed new duct routes would be time consuming and costly. A CP will not want to take the risk of dealing with all blocked/collapsed ducts, especially as there may be a legacy cost of lack of repair in the existing network.

84 New civil works – it is very likely that any new network would require the construction of new ducts on sections of routes. This could be due to lack of existing duct space, blocked ducts, collapsed ducts, or lack of access to existing duct space. The extent of new ducting that is required would be a key factor in the economic viability of duct access.

85 Proposed technology for deploying infrastructure – the nature of the proposed technology for any new deployment of fibre, and its related infrastructure, will impact upon all of the above considerations as, for example, a smaller diameter cable would be much easier to install in existing ducting.

86 Existence of electronic records – the existence of up-to-date electronic records may have accelerated the process of information collection for each route surveyed. During this project, all maps and plans from Openreach were sent in a paper format, and had to be scanned for communication around the project team. Whether these records are in electronic or paper format, they must be up to date and accurate to be of value to any future project.

87 Explicit engineering rules – The application of engineering rules is key when analysing the results, and a better understanding of the applicable Openreach engineering rules would have assisted with our interpretation of the survey results.

88 National security – providing access to Openreach infrastructure has a critical aspect, as it potentially provides access to communications medium that can be used in the context of national security e.g. Ministry of Defence communications. In this context it is important that Openreach retains full control of access to its ducts.

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5 Interpreting the results

5.1 Survey accuracy

5.1.1 Survey environmental conditions

89 Any interpretation of the survey results should take account of the environmental conditions during the field surveys. As stated in Section 4.2, there were a number of operational issues during the surveys, and these issues may have led to inaccuracies in the survey results. For example, under heavy rain, the surveyor had to look at the duct-ends and record on paper his findings, creating an environment prone to errors (record the wrong number of ducts on the form etc). However, the inaccuracies are not significant in terms of any assessment.

5.1.2 Cable and duct accessibility

90 Some survey inaccuracies occurred due to the arrangement of ducts and cables in chambers. Many chambers are extremely congested, with several layers of ducting and cabling, and it is not always possible to accurately observe the duct-end, e.g. if the duct-ends were in the middle of a highly utilised large duct nest. In addition, when cables are bundled, it can be difficult to count the number of cables in a bundle, e.g. the cables hidden in the middle of a bundle. However, these inaccuracies do not represent a statistically significant proportion of the overall 18 206duct-ends surveyed.

91 During the surveys, a number of inaccessible, or partly inaccessible, duct-ends were encountered, e.g. duct-ends partly covered by other cables, and duct-ends at the bottom of a duct nest with many cables above. In order to avoid the potential of damage/disturbance to cables, our survey team made no effort to move cables to create better access, and, hence, in reality, in some cases there may be more useable duct space than recorded. However, again, this factor is not statistically significant within the overall 18 206 duct-ends surveyed.

5.2 Duct continuity

5.2.1 Duct–end correlation assumptions

92 The field surveys were conducted from a duct-end perspective, and any study of duct continuity will be based upon an interpretation/correlation of duct-end results. From the survey results we have checked duct continuity along a duct route (from a chamber wall in chamber A to the next chamber wall along the route in chamber B) as follows:

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• the correct reciprocity of empty ducts/total no. of ducts between two adjacent chambers • the correct correspondence of ducts between adjacent chambers based on the number of cables

in the duct

• the relative positioning of duct-end in the duct nest in two adjacent chambers.

Considering the expected survey inaccuracies, and the random nature of the mismatches evaluated above, the checks executed did not show any factors that will have any impact on the conclusions of this study.

5.2.2 Collapsed/blocked ducts

93 As stated, this study considers duct continuity by considering the two ends of a duct section. This approach cannot detect/record, or take account of, any part of the duct section that may be collapsed or blocked. Full physical testing would be required to check for collapses/blockages. The consideration of the detection and repair of collapsed/blocked ducts is beyond the scope of this study.

5.2.3 Testing continuity

94 The only true test of duct continuity is a full physical test along the length of a duct route, e.g. the use of a rod/maul robot. This type of intrusive test involves a much higher risk of damage, or disturbance, to the incumbent cables, and was not carried out in the scope of the present survey.

5.3 Cable cross-over

95 Another factor to potentially affect the installation of a new cable in an existing duct is cable cross-over along the length of a duct section. For example, at a duct-end, existing cables may be in the bottom of a duct, and the potential useable space at the top of the duct; if along the length of the duct the existing cables cross over the duct to become positioned in the top of the duct, the useable space/new cable route could be eliminated. Since this study has considered only duct-ends, the consideration of the effect of cable cross-over has not been tested.

5.4 Duct accessibility in high usage chambers

96 In chambers with significant duct occupation, and a high number of cables per duct, not all potentially useable duct space will be accessible due to existing cables preventing access to other ducts. The tube methodology, described previously, takes account of this factor.

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5.5 Maintenance ducts

97 Any assessment of the availability of duct space will need to take account of the maintenance requirements of the owners of the existing cables in the ducts. It is reasonable to assume that if a cable fault involves a collapsed/blocked duct, the cable operator may wish to use a spare duct/duct space to run a new cable (temporary or permanent). It is also reasonable to assume that duct owners/cable operators, as a matter of policy, plan/build networks with capacity for maintenance/repair.

5.6 Copper recovery

98 In addition to the current duct space already identified, we have identified two potential economic drivers to realise additional duct space; the soaring price of copper, and an effective and cost efficient method of extracting copper cables from ducts. Some copper cables in Openreach’s network are unusable due to, for example, damage and old age, that obviously take up valuable duct space. Until recently the removal of unusable cable has not been financially viable, due primarily to the civil engineering costs required to recover the cable. However, recent soaring global demand for copper has pushed up raw copper prices, therefore making the recovery of unused copper cable financially attractive for organisations that own significant underground copper-based networks, such as incumbent operators. The extent to which copper can/will be removed, and therefore additional duct space made available, will be dependent upon two factors: • the level of risk of damaging adjacent fiber or copper cable when removing unusable copper

cable in the same duct • the raw price of copper.

99 Copper cables that have been stranded due to collapsed ducts may also be successfully recovered cost-effectively using new cable extraction technologies, such as Kabel-X6

. Kabel-X has patented a novel technique to extract underground copper cable from the original cable conduit without the need for digging, and therefore without incurring significant civil engineering costs. The conduit can then be used as a sleeve/pipe in which, for example, optical fibre cable can be inserted. This technique involves injecting a custom-designed liquid between the cable conduit and its core. This allows the cable to be drawn out of the conduit easily without having to dig, and without damage to adjacent cables. This technique potentially allows the cost-effective creation of additional duct space whilst retaining the integrity of remaining usable cable. It should be noted that this technology can only be applied to a cable with a robust outer sheath, which can be a significant constraint especially with older cables.

100 The removal of otherwise valueless stranded copper cables from current infrastructure will create additional space in the duct infrastructure, therefore having a direct positive impact on access to ducts if access were to be made available.

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6 Survey duct availability results

6.1 Introduction

101 The survey data set supports the analysis of two different types of result: • duct-end analysis

route continuity analysis.

102 The duct-end analysis considers all 817 chambers surveyed during this exercise, including 510 chambers on Type 1 routes, and 307 chambers of Type 2 routes (as defined in Section 3.1.1). The

duct-end analysis considers the duct-ends located on all four walls of each surveyed chamber. 103 The route continuity analysis considered 14 Type 3 routes, end-to-end from metro node to street

cabinet. While Type 3 routes are a combination of Type 1 and Type 2 routes, considering end-to-end routes from the metro node to the street cabinet provides a good indication of the potential capacity pinch points along the selected routes. The route continuity analysis considers the duct-ends located on the two walls of each surveyed chamber that are in the direction of the surveyed route. Duct-ends located on walls that are orthogonal to the route are not considered in the route continuity analysis.

6.2 Duct-end analysis

6.2.1 Overall survey results

Parameter Metro node to

exchange surveys (Type 1 routes) Exchange to cabinet surveys (Type 2 routes) Overall

Average no. of duct-ends per chamber

29.3 10.8 26.0

Average no. of cables per duct-end 1.9 2.2 2.0 Average % of empty duct-ends 28% 17% 26% Average unoccupied space per duct-end

36% 30% 35%

Figure 11: Main survey results [Source: Analysys Mason]

104 The average number of duct-ends per chamber increases with proximity to the metro node. This is in line with our expectation, as metro nodes are strategic network nodes that connect access and core network of Openreach’s infrastructure for all voice and data traffic (transit point).

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105 The average number of cables per duct is around two overall and does not significantly vary between Type 1 routes and Type 2 routes as shown in Figure 11. When analysing the data further, the vast majority of ducts (88%) have between zero and three cables in them, where a single cable in a duct is the most common occurrence (40% of the ducts).

26% 40% 13% 9% 5% 3% 1% 3% 0 cable 1 cable 2 cables 3 cables 4 cables 5 cables 6 cables 7 cables or more

Figure 12: Number of cables per duct-end [Source: Analysys Mason]

106 The average percentage of empty duct-ends is an important statistic, as it provides an indication of the infrastructure that could be used by third-party operators with minimum disruption to existing Openreach infrastructure (existing installed cable). Installing third-party cables in a duct that is already used by Openreach’s own cable is more risky, although sub-ducting would partially alleviate this risk. Figure 13 provides a summary of the number of empty duct-ends, full duct-ends and partially filled duct-ends.

Not full or empty 52% Full 22% Empty 26%

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107 The average distribution of unoccupied space per duct-end was determined using the 25mm tube methodology described in Section 3.3.3 to objectively assess the unoccupied space in the duct-ends. The distribution of unoccupied space is illustrated in Figure 13. Figure 14 shows that, overall 21% of all duct-ends surveyed have at least 70% of unoccupied space (five or more 25mm tubes can be inserted). This is in contrast with the previous figure of 26% of empty duct-ends described in Figure 13. To explain this, one needs to consider the congestion of a chamber, and the fact that empty duct-ends may not always be accessible due to other cables from other duct-ends in the same nest. In this context, of the empty duct-ends, 73% could accommodate five or more 25mm tubes, 17% could accommodate four 25mm tubes, 5% could accommodate three 25mm tubes, 2% could accommodate two 25mm tubes, 1% could accommodate one 25mm tube and 1% could not accommodate any 25mm tubes.

108 Also, considering the distribution for all chambers surveyed, it can be seen that 51% of all duct-ends have more than 42% of unoccupied space. This is an important result, as it shows that significant space exists within the Openreach network.

21% 13% 17% 16% 12% 22% 5 or more

more than 70% of unoccupied space 4 tubes 56% of unoccupied space 3 tubes 42% of unoccupied space 2 tubes 28% of unoccupied space 1 tube 14% of unoccupied space 0 tube 0% of unoccupied space

Figure 14: Total average distribution of unoccupied space in duct-ends [Source: Analysys Mason]7

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6.2.2 Detailed survey results

Duct-ends per chamber

109 Figure 15 illustrates the total number of duct-ends per surveyed chambers for Type 1 and Type 2 routes and per city/town. It should be noted that Type 2 route surveys were conducted in five cities/towns. The significant difference of duct-ends per chamber between Type 1 routes and Type 2 routes is consistent across all cities/towns surveyed. It can also be noted that there are significantly more duct-ends per chamber along Type 1 routes in large cities. This is expected as, in dense urban areas, more infrastructure needs to be deployed to address the denser demand. For Type 2 routes (closer to the user premises), there is very little variation between the different cities/towns surveyed, which would indicate that the infrastructure is normalised towards the cabinet. 0 10 20 30 40 50 60 70 Birm ingh am Car diff Cra wle y Cro ydon Gla sgow Leed s Man ches ter Milt on K eyne s Pete rbor ough Sou tham pton Step ney

Route Type 1 Route Type 2 Average

Figure 15: Detailed average duct-end per chamber [Source: Analysys Mason]

Cables per duct-end

110 Figure 16 illustrates the cable count per duct-end for different cities/towns. It can be seen that the number of cables per duct is consistently higher for Type 2 routes than for Type 1 routes for the cities/towns where we surveyed both types. This could be explained by the fact that, as the network reaches out towards the street cabinet, fewer and fewer ducts are available, as illustrated in Figure 15.

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111 The average of 2.0 cables per duct-end is consistent with the Openreach planning approach of generally overlaying an existing cable within an occupied duct, rather than using space within an empty duct. 0 0.5 1 1.5 2 2.5 3 3.5 Birm ingh am Car diff Cra wle y Cro ydon Gla sgow Leed s Man ches ter Milt on K eyne s Pete rbor ough Sou tham pton Step ney

Route Type 1 Route Type 2 "Average"

Figure 16: Average number of cables per duct-end [Source: Analysys Mason]

Percentage of empty duct-ends

112 Figure 17 illustrates the proportion of empty duct-ends (i.e. duct-ends with no cables in them) varies across the different cities/towns surveyed, from 7% for Crawley, to 44% for Cardiff on Type 1 routes, and from 9% for Manchester to 18% in Glasgow for Type 2 routes. In Cardiff, a significantly higher number of empty ducts is observed. This is due to a recent major infrastructure project that increased the capacity of the infrastructure network. In marked contrast, Crawley and Stepney show a significantly lower proportion of empty ducts due to a combination of high demand (dense urban centres) and possible lack of recent capacity upgrade.

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0.0% 5.0% 10.0% 15.0% 20.0% 25.0% 30.0% 35.0% 40.0% 45.0% 50.0% Birm ingh am Car diff Cra wle y Cro ydon Gla sgow Leed s Man ches ter Milt on K eyne s Pete rbor ough Sou tham pton Step ney

Route Type 1 Route Type 2 "Average"

Figure 17: Number of empty duct-ends [Source: Analysys Mason]

Unoccupied space per duct-end

113 Using the 25mm diameter tube methodology, described in Section 3.3.3, to measure the unoccupied space in the duct-ends, the distribution of unoccupied space was recorded for each of the surveyed cities/towns. A summary of the results is presented in Figure 18 for all Type 1 routes and in Figure 19 for all Type 2 routes.

22%

13%

17% 15%

11%

22% 5 or moremore than 70% of unoccupied

space 4 tubes 56% of unoccupied space 3 tubes 42% of unoccupied space 2 tubes 28% of unoccupied space 1 tube 14% of unoccupied space 0 tube 0% of unoccupied space

References

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