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Active Vs. Passive Optical Networks. ACE/RUS School and Symposium Corralling the Broadband Stampede. Presented By. Rob Wilkinson Vice President, Planning & Design. Technology Review. Passive Optical Network (PON) Generic GPON technology and topology
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Active Vs. Passive Optical Networks ACE/RUS School and Symposium Corralling the Broadband Stampede Presented By Rob Wilkinson Vice President, Planning & Design
Technology Review • Passive Optical Network (PON) • Generic GPON technology and topology • OLT (Optical Line Terminal) Splitter ONT (Optical Network Terminal) • Feeder fiber Distribution fiber Drop • Advantages • Lower cost for equipment • Smaller cross-section of fibers (lower cost) • Easy to add splitter for unexpected growth • Disadvantages • Reduced bandwidth to subscriber (2.4 Gbps shared) • Limitation of distances to sub (20 Km with 32:1 splits)
Technology Review • Active (Dedicated Plant) • Active Ethernet technology and topology • OLT (CO or field electronics) ONT (Optical Network Terminal) • Feeder fiber Distribution fiber Drop • Advantages • Maximum bandwidth to each subscriber (1 GB per sub) • Distance to subscriber could reach 80 Km (50 mi) • Most future safe – not as concerned about an evolution plan • Disadvantages • Larger fiber cross sections to meet present and future growth • Typically higher cost electronics
Approach • Identify and Define Study Areas • Three types of study areas • Low density, low growth rural area • High density, high growth rural area • Urban area • Design & Costs • Used a “square” layout scenario for consistency • Cable sizing was completed using a cable fill chart • Economic breakeven years • Percent growth • Costs do NOT include common costs of both scenarios (not project costs)
Study Details • Study Areas • Low density, low growth rural area • 100 square miles • 2 subs per route mile • 140 route miles/280 subs served • 2% growth per year • High density, high growth rural area • 100 square miles • 10 subs per route mile • 140 route miles/1400 subs served • 6% growth per year
Study Details • Study Areas • Urban Area (approx. 5,000 population) • 144 blocks (12 blocks x 12 blocks) • 16 subs per block • 23 route miles/2304 subs served • 2% growth per year
Study Results • Low density, low growth rural area • Small difference in cost (11%) • PON = $1,795,000 • Active = $2,015,000 • High density, high growth rural area • Even smaller difference in cost (8%) • PON = $3,445,000 • Active = $3,729,000 • High density urban area • Higher difference in cost (29%) • PON = $1,469,000 • Active = $2,071,000
Study Results • Technical Differences • PON has varying distance limitations which could impact fiber sizes • Changing splits can extend reach • Standard Active reach is 20 Km, but could go 80 Km with extended lasers • Enhances reach in low density very rural areas • Distance is less important in high density areas vs. fiber cross sections • Place additional electronics within area to keep fiber sizes lower and manageable • Bandwidth capacity • PON provides shared bandwidth to customer • Active provides dedicated bandwidth to customer • Each has a common bottleneck to the world (10 GigE backplane)
Conclusions So what’s the answer? It’s a bladder control issue! It DEPENDS!
Conclusions • Cost Basis • PON still provides the lowest cost scenario • Technical Basis • Active provides maximum amount of distribution bandwidth at minimal cost increase • How do you chose? • Do BOTH!!!