DARK FIBER IN SERBIAN NREN

1. DARK FIBER IN SERBIAN NREN SOLUTIONS, PLANS AND ACTIVITIES Pavle Vuletić, Zoran Jovanović, Belgrade University Computer Centre - BUCC Serbia & Montenegro vpavle@rcub.bg.ac.yu, zoran@rcub.bg.ac.yu

2. Telecommunications background • Telekom Srbija – monopoly until June 2005 • Telekom Srbija is (almost) the only owner of intercity fibers • Telekom Srbija does not lease dark fiber • Expensive high capacity digital links • Intercity 155Mbps – 31.000 €/month • Intercity 622Mbps – 92.000 €/month

3. Alternative dark fiber network (1) • End of 2001. Establishment of alternative dark fiber infrastructure – workgroup formed • Ministry of telecommunications, • Ministry of science, technology and development • NIS, Serbian oil and gas distribution company • EPS, Electric power industry of Serbia • ŽTP, Serbian rail • PTT Serbia • Serbian NREN (RCUB)

4. Alternative dark fiber network (2) • Alternative dark fiber project failed • Telekom Srbija more cooperative for the initiatives from the Government • EPS installed OPGW cable on Belgrade – Hungarian border and Belgrade – Croatian border lines • Other companies (NIS, ŽTP) have small parts of fiber network installed • NIS is installing fiber on all new pipelines • In cities fiber is being installed in heating and water pipeline channels

5. Year 2002 • SinSEE Project: Donnation from the German ministry for science and technology in active networking equipment: • Fiber lines established: • RCUB-Rektorat (5km) • RCUB-Novi Sad (95 km – 23dB attenuation) • RCUB-Vinca (15km) • All lines installed and working

6. Year 2003 • Contract with Telekom Srbija – Q3 of 2003 • Novi Sad – Subotica (130 km) • Beograd – Kragujevac (130 km) • Beograd – Niš – Gigabit Ethernet over SDH (250 km) • Lines are not yet provisioned • 8 locations in Belgrade • 3 locations in Novi Sad • 2 locations in Kragujevac • 4 locations in Niš

7. Year 2004 • Annex of the contract with Telekom Srbija • Phase 1: • Subotica – Szeged! (40 km) • Phase 2: • Novi Sad – Zrenjanin • Beograd – Šabac (90 km) • Beograd – Valjevo (90km) • Valjevo – Užice (89 km) • Užice – Čačak (58 km) • Čačak – Kraljevo (33 km) • Kraljevo – Kruševac (83 km) • Kruševac – Niš (84 km) • 3 locations in Belgrade

8. Year 2004 • Annex of the contract with Telekom Srbija • Phase 3: • Beograd - Pančevo (20 km) • Kraljevo – Novi Pazar (91 km) • Niš – Pirot (71 km) • Niš – Leskovac (46 km) • Leskovac – Vranje (68 km) • Niš – Bor (130 km) • Novi Sad – Sombor (72 km) • 2 locations in Belgrade

9. Locations in Belgrade

10. Total fiber length • Price for domestic dark fiber lease per month is very close to the dark fiber price in deregulated telecommunications markets • Total inter-city fibers: Approx. 1400 km • Total intra-city fibers: Approx. 150km

11. Dark fiber timeline • All the lines from the first contract with Telekom Serbia were supposed to be finished by the end of 2003 • Slow dark fiber service provisioning • Problems with different permissions for last mile installations especially if digging is necessary • Phase 1: May 2004 • Phase 2: September 2004 • Phase 3: November 2004

12. Equipment and technologies • Gigabit Ethernet • Low cost interfaces • Use of low cost L2 or L3 switches • More then 100km range • Sufficient at the moment in Serbian NREN • Use of CWDM

13. NS Cisco 3550 BG Cisco 6509 CWDM test – July/August 2003 • Cisco CWDM test kit • Replaced 1000BaseZX • Belgrade – Novi Sad (95 km – 23dB att.) • 4 Gbps Etherchannel 1470 nm, 1510 nm, 1550 nm, 1590 nm CWDM MUX-4 CWDM MUX-4

14. Total attenuation • Telekom Srbija has G.652 fibers • Total attenuation approx: 23dB+3dB+4dB = 30dB • CWDM 1000BaseZX optical budget: 30dB • Problems expected on 1470 nm • 45 days without any carrier transition

15. CWDM experiment conclusions • Can be used on intercity lines (100km) • Reliable solution, • Low cost solution • Easy bandwidth upgrade • Great flexibility for different logical topologies

16. CWDM Problems • Problem with signal amplification: • EDFA cover narrow wavelength range (typically C-Band or L-Band) • More then one EDFA must be used in order to cover more then two wavelengths (1530nm and 1550nm) • EDFA - Expensive solution (Offer: 54.000 € (price with a discount for academic institutions) for Belgrade – Subotica – 220km for 4 wavelengths (1510, 1530, 1550, 1570nm) – two preamplifiers and two boosters) • LOA – Cover broader wavelength range. At the moment of our analysis were available only as product evaluation kits. Offer: 2500$ per LOA and 2000$ per evaluation kit for 12dB amplifier

17. Our solution • OEO conversion using L3 switches • Drawbacks – in totally Ethernet network – relatively slow convergence, added delay • Idea: Justify the use of dark fiber through fast and cheap connection provisioning. Later find the best solution for the network

18. Potential Belgrade – Novi Sad – Subotica - Hungary connection

19. Southern part of the network • All distances less then 100km • Easy logical channel separation for cross-border connections • Already purchased one 4-wavelength CWDM kit (multiplexers and interfaces) which will be used for CWDM testing on all lines. • Active equipment (switches) already purchased for all the cities

20. Conclusion • Widespread use of inter- and intra-city dark fiber is the main direction in which Serbian NREN is moving • Cross-border dark fiber connections in SEE region are the next step for inter-NREN connections • CWDM is a technology which will most probably Serbian NREN use in the near future

21. Thank you for your attention Questions