Access optical cross-connect node 2 Optical add drop multiplexer FTTH = Fibre to the home FTTA = Fibre to the antenna Figure 4.54 Sharing investments in fixed and mobile access in a metropolitan area Telecom Business Business Model Flow Diagram 1 Network model Homes/Businesses Passed Access services in use End user Application Traffic forecasts Model Existing Network Infrastructure Future Network Rollout Strategies Migration Strategy Sites/Network physical Market layout model Media and transport Access nodes/local nodes/core nodes Telecom Cost input sheets Business Network Traffic distribution Access characteristics Local operator costs Core operator costs Service implementation costs Financial Network operations model costs Figure 4.55 Many access parameters influence the business case for network solutions If permitted by regulators fixed and mobile accesses will probably converge. Going the UMTS way also makes network sharing a possibility, in order to decrease overall investments and improve ROCE. Another interesting feature would be to enhance bundled fixed and mobile offering. See Figure 4.54. Introducing IP/Ethernet on Fibre Systems According to source information from Yipes, Dell 'Oro, Yankee Group, Extreme Net- works, Juniper Networks, compiled at Ericsson, the cost components equipment, band- width management and annual upgrades are much cheaper for IP/Ethernet than for IP/ ATM/SONET or IP/SONET. For a regional network with five hubs and 10 rings the cost might just be about 20% of the other alternatives. Using Computer Programs for Access Optimization In order to achieve optimal cost efficiency a computer program might be useful, or even necessary. The reason is the very large number of parameters that are involved in network optimization. See the computer program model in Figure 4.55. The calculations are made according to a financial model and expressed for example in net present value (NPV) or internal rate of return (IRR). A typical go/no-go value of IRR could be 15 %. Services 5.1 INTRODUCTION 5.1