Programmable logic design for an optical access network

1. Programmable logic design for an optical access network S-38.310 Thesis Seminar on Networking Technology, 27.5.2003 Sami Lallukka

2. Outline • Background • Optical Access Networking (OAN) project • Communication networks today • Communication networks tomorrow • One solution for future metropolitan area networking • OAN network demonstrator • HDL design for the demonstrator • Results of the thesis • Future work

3. Background • Thesis written as a part of OAN research project at VTT Information Technology, Broadband Communications. • Goals • Define requirements for future optical access networking • Find ways to support these requirements • HDL design for the FPGAs in the OAN network prototype • Supervisor: Prof. (pro tem) Samuli Aalto, HUT • Instructor: Lic.Sc. (Tech.) Kari Seppänen, VTT

4. Optical Access Networking (OAN) project • TEKES-funded project, duration: beginning of 2001 - end of 2003 • Participating HUT, VTT, Nokia, Elisa • VTT Information Technology - Electrical equipment • VTT Microelectronics - Optical network solution • HUT Networking Laboratory - Teletraffic theory • Goal is to define and demonstrate a fast optimised access feeder/distribution network • Future requirements in metropolitan area networking need to be defined first. These are • Service operability issues • Traffic characteristics • Technologies available

5. Communication networks today • Three separated networks • Telephony • Data communications • Broadcast • Overlaid structure in telecom and datacom • Complex access network • Bottleneck in MAN • Expensive to maintain

6. Communication networks methodology • Distribution networks - interface towards end-users • Feeder networks - traffic towards and from WAN • Backbone networks - high speed trans. • Access networks - collect and convert • Transport networks - data transportation

7. Traffic characteristics today • Networks are optimised for one type of traffic only (except SDH/SONET) • Only same type of traffic can be concatenated forming larger flows - SDH/SONET widely utilised • Interworking functions located in metro region (tech. conversions) • Connectionless and connect-oriented traffic • Adequate QoS can be provided only for connectionless traffic • Services located geographically over long distances (centralised) • most of the traffic goes through WAN • New services emerging - need for more flexible network structure • security and privacy • streaming media and real-time

8. Communication networks tomorrow • Separated networks converged into single automated transport network • Composed of hybrid networks with transparent transfer • Passive Optical Networks (PON) main technology in access • WDM widely utilised, especially in metropolitan area • Fully optical and almost real-time wide area transport network • Automatic configuration with automatic switching

9. Traffic characteristics tomorrow • Connectionless, connection-oriented and real-time traffic • Interworking functions from access to distribution networks • Intelligent servers - traffic concentrated in MAN • Transparent transfer enables the transport of different technologies over the same transport network • Adequate QoS for new services (real-time) • Survivability issues important • Automatic configuration and maintenance (cost reduction)

10. Data over SDH/SONET (DoS) - solution for future networking • Utilises manageable and widely used SDH/SONET transport • Can later use Optical Transport Network (OTN) solutions • DoS standard already supports number of access and transport technologies and even more in future • Flexible two-layer transport solution enables transparent transfer • Standardised by ITU-T

11. OAN network demonstrator - optical network • Physical network - WDM with optical protection • Topology: physical RING - logical STAR • Every node directly connected to the HUB with their own wavelength

12. OAN network demonstrator - Node • Access network - 2,5 Gbps SDH + 2 x Gb Ethernet • Compact PCI frame, separated router and interface cards • Network functionality implemented in three FPGAs • Transport network - 2,5 Gbps SDH links

13. OAN network solution • Data over SDH/SONET (DoS) • Generic Framing Procedure (GFP) • provide the transparent transfer • Virtual Concatenation (VC) • efficient bandwidth allocations • Link Capacity Adjustment Scheme (LCAS) • adjustments for bandwidth allocations • Support for RPR, Ethernet, MPLS, PPP, ATM

14. HDL design for the FPGAs • Network - GbE HUB, POS support, DoS with APS, VC with SDH framing • Control - Wavelength tuneable lasers, 12 MB SRAM, PCI interface

15. Results of the thesis work • Requirements and solutions for future metropolitan access networking • Bandwidth increase in metro region - WDM utilisation • More flexibility and scalability for networking - DoS • QoS for new services - DoS • Automatic configuration and maintenance - ASTN, ASON • HDL design for the functionality of metropolitan optical feeder network • Utilises DoS with Automatic Protection Switching (APS) • Controls tuneable WDM network

16. Future work • Based on the design presented here, a HDL implementation for the FPGAs in the OAN demonstrator will be created • Variety of testing will be made with the demonstrator, concentrating on metropolitan and access networking • Based on the testing results, possible new revision of the network might be designed and built • OAN demonstrator could be used as a basis for future development in access area networking