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.
Raspberry Pi 5: Challenges and Solutions in Bringing up an OpenGL/Vulkan Driv...
The race to 1Gbps and beyond: Evolution of broadband access networks
1. The race to (X)Gigabit
Network Access
From historical xDSL & DOCSIS copper
to nowadays
mixed/all optical network
1
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
3
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
5
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
8
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
9
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
10
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)
11
12. Carrier’s subscriber services
• From Simple TDM to full Triple Play
• Up to CATV RF overlay
IPTV
Phone
PC
SFU
OLTSplitter
12
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
13
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.
14
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
15
Form factors (ONT, SFP Stick)