Impact of new cabling techniques on Italian access network

1
Impact of new cabling techniques on Italian
access network

• Gianluigi Azzarello - Telecom Italia
• Giuseppe A. Azzini - CSELT

2
Outline

• Introduction
• The Italian optical access network
• The new cabling techniques
• An economical and technical evaluation
• Conclusions

3
Introduction

• Fibre in the loop large penetration
• Increasing demand for bandwidth
• TLC equipment installed in the field
• Strong impact of costs
• reduced sharing of costs among customers
• services are made possible by cost reduction
• Network flexibility
• stringent time to market needs
• fast network reconfigurability

4
The Italian Optical Access Network

• Started in 1991
• large business customers,
• HFC and digital equipments
• Two network topologies ring, star
• Cable installed in ducts using traditional and
  innovative techniques
• PE pipes, corrugated PE tubes,
• Use of no-dig techniques for civil works

5
The cable and network materials

• Fibre rings based 100 fibre ribbon cables

• Use of mixer for dual path connection

6
The Ring structure

• Dual Path for increased network reliability
• Used when the POTS number gt4000
• Typ. length gt2.5 Km, lt12 Km
• Based on 100 fibre cables

7
The Star Structure

• Reduced costs
• Used when the POTS number lt4000
• Typ. length lt 5 Km
• Presence of a virtual ring

8
The new cabling techniques

• Air Blown Fibre
• British Telecom patented
• Widely diffused in U.K. access networks
• Full product range available
• Pulled Fibre
• Same concept and materials of ABF
• More simple but less performant on long and
  tortuous routes
• Copper in Tube
• suitable mostly for FTTH architecture

9
The techniques performances

• Air Blown Fibre
• Typical reachable length with single operation
  1500 m (available tandem configurations)
• Typical installation speed 40 m/min
• Applications both for access network and LAN
• Pulled Fibre
• Typical reachable length with single operation
  700 m (available tandem configurations)
• Typical installation speed 15-20 m/min
• More simple installation equipment

10
An economic evaluation the criteria

• Example from an urban optical ring already
  installed
• Ring length chosen to be compatible with
  techniques performances
• Evaluation not inclusive of civil works
• Costs for standard solution calculated from
  Telecom Italia data
• Focus on the optimal solution
• Fixed cost for installing fibres

11
The Ring schematic structure
12
The first solutiontraditional cable and new
tech in the drop

• Tubes cables only in the drop section
• Minimum ducts occupation
• Short installation lengths
• Drop section less than 9 of total cables length
• Mixed technologies

100 fibres cable ring
Branching enclosure with mixers
2 Tubes cables
13
The second solution TTCustomer

• Each customer is connected using two dual path
  tubes
• Reduced number of splices
• It requires the installation of two 19 tubes
  cables
• Tandem and central solution for installing are
  required
• Single technology solution from central office
  to the customers

14
The third solution new techniques and mixers

• Reduction of bundle and tubes amount
• Reduced ducts occupation
• Long installation lengths
• Special materials required

19 tubes cable
Branching enclosure with mixers
2 Tubes cables
15
A new ring design schematic structure
16
The adoptable solutions

• Tube to the home
• Long lengths to be reached
• Mixed traditional cables and new ones
• Drop equal than ring one
• New techniques and mixers
• Requires too many mixers

17
A costs comparison
18
Future perspective for optical access network

• The new techniques can have a strong impact also
  on civil works, where the costs are mainly
  concentrated
• The flexibility allows a two stages approach
• the first customers are connected directly to the
  central office with an eventual dual path
• when the number of customers increases, a
  complete optical ring based in the backbone
  section on traditional cable is possibly deployed

19
Conclusions

• The new techniques can have a positive impact
  for costs and time to service
• The flexibility can strongly modify the design
  approach for optical access networks
• The techniques can be successfully applied to
  Rings in Italian Access Network
• The availability of techniques with longer
  installation span can disclose new approach for
  cabling in urban areas