1. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Technological problems and solutions in optical network plants in the last years in Hungary Hungary as a model of Middle-East European countries Edith MÁRKUS MATÁV HTC PKI Development Institute

2. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Technological problems and solutions in optical network plants in Hungary (Hungary as a model of Middle-East European countries) Regarding the telecommunication development Hungary can be considered as a model of the Middle-East European countries. In this part of Europe the telecommunications development tendencies are similar to each other and the Hungarian steps can be characteristic. The revolutionary progress of transmission technology of 70s and 80s had to be followed an intensive expansion of network capacity. This possibility was given by the layout of optical cable network. In this paper we can view the different techniques applied to optical cable network installation in the last ten years when more than 5000Km optical cable has been planted in Hungary. Paper shows the advantages and disadvantages of them, the problems and their solutions, the opposite tendencies in design and installation of optical cable network caused by the contrast cost effectiveness with safety, future proofness or flexibility of the network. Abstract

3. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Technological problems and solutions in optical network plants in the last years in Hungary Hungary as a model of Middle-East European countries Technological decisions in network design. Economical aspects of choosing technological solutions Advantages and disadvantages of the chosen technological solutions in practice Existing technological problems to be solved nowadays

4. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Hungary as a model of Middle- East European countries 1950-1968 Minimal development of the existing telecommunication network 1968-1990 Slower development then increase of demands (5.5% / year) 1990-1998 INTENSIVE development (more than 13% / year) 1993-1996 Different privatisation steps

5. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 1950-1968 lead sheathed paper insulated copper cable network 1968-1990 coaxial trunk cables PE sheathed filled copper cables optical cable field trials 1990-1993 installation of optical cable junction and trunk network 1993- installation of optical cable rural and access network Hungary as a model of Middle- East European countries

6. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Technological decisions in network design Use of -direct buried or duct cables -metalfree cables or cables with metal elements -joint types Influence on -cable length between joints -number of joints in a section -required splice attenuation (attenuation budget)

7. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Economical aspects of choosing technological solutions Long haul trunk network: -cost effectiveness against safety and future proofness Access network: -cost effectiveness against safety and flexibility

8. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Example 1:First optical cable transit line Budapest-Vienna Cable: loose tube type armoured cable with filled space containing 5x10 fibres Laying: direct burying with plough Joints: splices Joint closures: placed in direct buried protective iron sleeves

9. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Example 1: First optical cable transit line Budapest-Vienna Advantages: length of laid cable can be 4-6 km simple laying techniques less joints in a section Problems: lot of crossings on the cable route earthing of metallic part Disadvantages: no simple crossing techniques additive joints only for earthing cable laying is more time- consuming then it was planned

10. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Example 2: Optical cable junction network Cable : loose tube type metalfree duct cable with filled space containing 10-50 fibres Protection : cables placed in plastic pipes Laying of pipes : two pipes (one spare) direct buried with plough or laid in open trench Cable plant : blown in or floated with water into the pipes Joint closures and cable extra lengths : placed in direct buried concrete boxes

11. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Example 2: Optical cable junction network Advantages: simple laying techniques of tubes spare tubes can be laid in advance simpler crossing techniques no earthing problems one joint enough to repair cut cables Problems: to find the metalfree cable branching joints needed later Disadvantages: max 2 km length is pulled in more joints in a section special signs of cable route

12. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Splice loss requirements of junction network section length > 50 km individual loss: max. 0.15 dB cable average: max. 0.05 dB section length < 50 km individual loss: max. 0.15 dB cable average: max. 0.08 dB

13. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Distribution function of splice losses in the junction network

14. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Cable loop preparation for later branching

15. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Example 3: Optical cable access network System: AON FTTC (or FTTB) Cable: decimal system change to 12 fibre bundle system -core network: loose tube type metalfree duct cable containing max. 192 fibres (16x12) - distribution network: max 72 fibre multitube duct cable and 12 fibre single tube drop cable Protection: -core network: cables placed in plastic pipes -distribution network:10% direct buried cables

16. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Example 3: Optical cable access network Joints: tendency to change to flexible access joint type -cable led in with looped uncut tubes -positive fibre management -possibility of single circuit management Protection of joint closure and cable extra length: -core network: placed in manholes or direct buried concrete boxes -distribution network: 10 % of joints are direct buried

17. Problems and solutions in optical network plants in Hungary Torino, 30-31 March 1998 Example 3: Optical cable access network Advantages: -dark and spare fires in cables for future use -possibility of SDH rings for key customers Problems: -no flexible fibre management in OLD street cabinets and ONUs - splicing of fibres needed later Disadvantages: -direct buried cables without protection -missing flexibility of direct buried joints