The document discusses trends in broadband network access, including increasing speeds up to 1 Gigabit per second (Gbps) and the evolution from copper-based to optical fiber networks. It focuses on the use of passive optical networks (PON) to deliver high-speed broadband access over longer distances in a shared, cost-effective way. PON uses fiber and passive splitters to deliver broadband to multiple customers simultaneously without active electronics at user locations.

1. The race to (X)Gigabit
Network Access
From historical xDSL & DOCSIS copper
to nowadays
mixed/all optical network
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Zaccone Carmelo 09/18

2. Observations on Broadband evolution
• ICT and communication technologies are the backbone of the digital
economy and society
• Evolution of the market players (mainly related to the changing
nature of the subscriptions)
• Network Operators: continue the business in “access path & connection”
• Over The Top: increasing offering in ”service & application”
• Evolution of the consumer behaviour
• Content: subscription vs acquisition based
• Usage: on-demand/online vs download/offline
OECD Digital Economy Outlook 2017
http://www.oecd.org/sti/ieconomy/
http://www.oecd.org/sti/broadband/broadband-statistics/ 2

3. Trends (fixed): access, subscriptions, speed,
services
• Speed, a perception closely linked to the century (from ’90 Kbps, early
‘2K Mbps, current 100Mbps+)
• New hype is (X)1Gbps
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4. Trends (mobile): access, subscriptions, speed,
services
• Exponential speed evolution leads to data consumption boom
• Mobile goes ‘data hungry’ embedded devices
• IoT, SmartCar, etc
• 4G, 5G, (WiGiG 802.11ad) etc key wireless enabler
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5. One answer to Telco: PON (passive optical network) based NA
• Extend the reachability of the (metro)core network thru higher speed
access
• Increase the coverage of the high speed access network by sharing
former dedicated P2P links
• Fitting (ITU-T G.9964) into Broadband Forum reference architecture
(TR-101 ATM 2 Eth aggregation) with TR-156 (GPON access) or TR-167(GPON feding) or TR-331(GPON mobile backhaul)
• Replace xDSL customer access or
• Bring the street cabinet/mobile RAN
closer to the customer
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6. FTTx roll out flavours
• Fiber-to-the-curb (FTTC)
• Fiber-to-the-DistributionPoint (FTTdp)
• Fiber-to-the-cabinet (FTTCab)
• Fiber-to-the-Building (FTTB)
• Fiber-to-the-home (FTTH)
• Fiber-to-the-office (FTTO)
• Fiber-to-the-user (FTTU)
FTTH Handbook
http://www.ftthcouncil.eu/
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7. PON components
• Optical Line Termination (operator side)
• Passive Optical Network
• Optical Wavelenght
• Upstream 1310nm,
• Downsteam 1490nm,
• RF overlay 1550nm
• Passive Optical Splitter
• ratio max 128, 32/64 typical
• Bandwidth
• Upstream 1.244 Gb/s,
• Downstrem 2.488Gb/s
• Typical: Optical budget 28db for 20km with split 1:32
• Optical Network Termination/Unit (customer side)
• Standards ITU-T G.984.1 G.984.2
System req Physical layer
G.984.3 G.984.4
Protocol Layer Management layer
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8. PON architecture & transmission basic
• Bi-direction communication over a single fiber
• Wavelength Division Multiplexing technology
• Multiplexing mechanism
– downstream, data packets are transmitted in a broadcast manner,
– upstream, data packets are transmitted in a TDMA manner
• Round Trip Delay & Equalization Delay
• avoid occurrence of upstream transmission collision on optical splitters
Different PON types:
• APON: ATM Passive Optical Networks
• EPON: Ethernet Passive Optical Networks
• GE-PON: Giga-bit Ethernet Passive Optical Networks
• GPON: Gigabit-capable Passive Optical Networks
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9. Topology protection mode
• Fibre backup
• Primary fails -> secondary takes up
• No backup for ONU
• OLT interface backup
• Primary fails -> secondary takes up
• No backup for ONU
• Full protection (complex & not cost effective )
• Recovery of various faults
• Backup also for ONU
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10. GPON multiplexing (Transmission Convergence Layer = Data Link from OSI)
• ONU Identifier
• OLT assigns 8-bit identifier (ONU-ID) to ONU during activation (PLOAM)
• Allocation Identifier
• OLT assigns 12-bit number (Alloc-ID) to identify an ONU upstream traffic-bearing (to be mapped to a T-CONT)
• Transmission Containers (T-CONT)
• ONU defines group of logical connections that appear as a single upstream bandwidth for the PON (to be mapped to an Alloc-ID)
• 4 traffic categories:
• FB (Fixed Bandwidth): Reserved upstream Bandwidth, cyclically allocated regardless of demand
• AB (Assured Bandwidth): Similar to fixed but Bandwidth not given without demand
• NAB (Non-Assured Bandwidth): Bandwidth only given if available but not guaranteed
• BE (Best Effort): demand only met if remaining upstream Bandwidth is available
• Generic Encapsulation Method (GEM)
• ONU logical connection (Port-ID) associated with a specific traffic flow
• encapsulating of user data frame for transport over the PON
QoS queues
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11. Mapping subscriber (Eth) data into
carrier (GEM) PON link
• GEM Framing data encapsulation
• Place the user data frames inside the PON transmission slots
• Identifies each frame as belonging to a connection / ONU / subscriber
• Permits fragmentation and reassembly
• Dynamic Bandwidth Allocation
• peak bandwidth(s) not required all the time
• optimizes usage of the shared medium
-> Oversubscription levels and Service Level Agreements (SLA)
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12. Carrier’s subscriber services
• From Simple TDM to full Triple Play
• Up to CATV RF overlay
IPTV
Phone
PC
SFU
OLTSplitter
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13. Extra for the tech hungry
Broadband Forum TR-156
Using GPON Access in the context of TR-101
Broadband Forum TR-247/ATP-247
Abstract Test Plan for GPON ONU Conformance
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14. Ethernet services across GPON
scenario & interoperability/conformance
• Ex. deployment scenario
• TR-101
• Defines port configurations to support Application Service Provider, Network Service Provider and Transparent LAN Service ( Business Ethernet services)
• Identifies two Eth VLAN topologies (N:1 and 1:1)
• ONU responsible of ingress (to subscriber LAN) traffic classification for the U interface.
• OLT responsible of ingress (to operator network) traffic classification for the V interface.
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1:1 permits double-tagged Eth
to overlay (TLS) the customer VLANs
http://www.broadband-forum.org/standards-and-software/technical-specifications/technical-reports

15. GPON ONU conformance
• Hundreds of network topology scenario
• Similar to IP Network (Port) Address Translation but on Eth VLAN Tags
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Form factors (ONT, SFP Stick)