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FTTH. Fiber To The Home. Alpesh Desai SDE BB, RTTC Ahmedabad. FTTH. Today, majority of broadband connectivity is offered through Digital Subscriber Line (DSL), Cable Modem and to the limited extent with Wireless technology.
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FTTH Fiber To The Home AlpeshDesai SDE BB, RTTC Ahmedabad
FTTH • Today, majority of broadband connectivity is offered through Digital Subscriber Line (DSL), Cable Modem and to the limited extent with Wireless technology. • FTTH which provides Higher Bandwidth is future proof solution for providing add-on services such as Video on demand, Online Gaming, HDTV etc
What is PON? PON - Passive Optical Network • It is cost effective optical fiber based access system • It provides triple play services (voice, video & data) to customers
Why PON required? • Due to bandwidth limitation of copper cable, Optical signal is to be distributed on Fiber • PON provides High bandwidth with reduced COST & complexity • No conversion required for O-E-O • PON uses optical fiber and optical power splitters
Why PON required? • High bandwidth requirement for Voice, Data & Video at Distribution / • User end Bandwidth required for • Hi definition TV, • High speed internet access, • High speed data transfer, • Video on demand, • IPTV, Online gaming, Distance learning, etc.
P O N FIBRE Central Office (CO) Customer Premise Equipment (CPE) PON
Types of PON configurations • Point-to-point Ethernet • Point-to-multipoint switched Ethernet • Passive Optical Splitter
PON configurations Point To Point CO P2M Switched Ethernet CO Passive Optical Splitter CO
Voice NMS Data ONU Other Networks Video TDM ONU Video/Audio over IP services PABX OLT PON 1:32(64) Optical Splitter CATV overlay services TDMA Central Office IP N/Ws Data ONU 0-20 Km physical reach (60 Km logical reach supported by protocol) FTTH Architecture
Elements of PON • The basic elements in any PON system are: • OLT : A Central Office (CO) equipment providing PON with the various network interfaces • ONU/ONT : An External Plant / Customer Premises equipment providing user interface for many/single customer • PON :Passive optical splitters/combiners providing connectivity between OLT & multiple ONU/ONTs through optical fibers • NMS : Management of the complete PON system from OLT
1. OLT: • OLT resides in the Central Office (CO) • OLT provides switching functionality between the core network (various network interfaces) and PON • OLT is typically connected to: * IP network and * Backbone of the network operator
2.ONU/ONT • ONU/ONT provides access to users i.e. an External Plant / Customer Premises equipment • providing user interface for many/single customer • installed within user premises for network termination is termed as ONT • Access node installed at other locations i.e. cabinet /building, are known as ONU
3. PON: • Distributed or single staged passive optical splitters /combiners • provides connectivity between OLT & multiple ONU/ONTs • Connectivity through one or two optical fibers • Optical splitters are capable up to 1:64 optical split, on end to end basis. • These are available in various options like 1:4, 1:8, 1:16, 1:32 and 1:64
4.NMS:Management of complete PON system from OLT • One OLT serves multiple ONU/ONTs through PON • TDM/TDMA protocol Single Fiber/ Dual Fiber to be used for upstream & downstream • Protection for taking care of fiber cuts, card failure etc. • Maximum Split Ratio of 1:64 • Typical distance between OLT & ONT can be greater than 15Km (with unequal splitting - up-to 35Km) • Downstream transmission I.e. from OLT to ONU/ONT is usually TDM • Access from ONU/ONT to OLT is TDMA
Bandwidths & Services Upstream Downstream 1310 nm 1490 nm 1550 nm Voice and Data Voice and Data Video Data Power & Battery Video Bandwidths & Services POTS ONT ONT
802.3x frame FCS Payload Header 1 4 4 4 4 4 4 3 3 3 3 3 3 2 2 2 2 2 2 1 1 1 1 1 1 2 4 3 2 1 3 // // 4 Downstream Traffic in EPON // // OLT ONU 1 ONU 2 // // // Maximum 64 ONUs can be configured Every ONU receives the original Frame which was sent from OLT ONU filters only the traffic meant for that site with the help of an ID Downstream traffic is normally encrypted to avoid security breach // // ONU 3 ONU 4 //
802.3x frame 1 1 Header Payload FCS 1 2 2 2 1 2 3 4 3 3 3 4 // // 4 4 Upstream Traffic in EPON (TDMA) // // OLT ONU 1 ONU 2 // // // ONUs share the bandwidth in TDMA Fashion when sending the traffic to OLT (upstream) Sufficient gap ( laser off) is maintained between frames from ONUs to avoid overlapping Upstream traffic from one ONU cannot be seen by other ONUs by the Physics of Splitter/coupler // // ONU 3 ONU 4 //
Multi- Point-Control-Protocol (MPCP) • The OLT needs an arbitration scheme (MPCP) so it can schedule and control the traffic coming from the ONUs • OLT sends a GATE (grant) message in the downstream channel to the ONU, in which transmission information (start time, transmission length) are included.
Multi- Point-Control-Protocol (MPCP) • ONU sends a REPORT (request) message in the upstream to the OLT at the end of its transmission to notify the OLT of its buffering queue status. • OLT needs to take distance(between OLTs and ONUs), traffic priority and QoS problems into account while granting access to ONU
Types of PONs • EPON (Ethernet Passive Optical Networking) (Japan) • GPON (Gigabit Passive Optical Networking)
Video Services • Transports 89 Channel PAL CATV Analog Video Channels over dedicated 1550nm wavelength • Bandwidth of 45 – 862 MHz
Application Areas – Wireless Backhaul Applicable ONT Types: B-ONU – Cat I
Protection in GPON • Full-Tree Protection • Some ONTs may be not protected • Double fiber route to a protected ONT
GigE Switch Ethernet Transport ADM MADM SDH Transport Splitter 1:N OLT PON Access ONT ONT ONT ONT ONT Central Office Fiber Distribution Access Network GPON Architecture
Applications VPLS, VPLAN E1 PBX STM1 CPE replacement Basic Telephony (SIP) Cable TV, IP TV Applications Internet Browsing Basic Telephony (SIP) Cable TV IP TV Applications VPLS, VPLAN Internet Access E1 IP DSLAM interface Cable TV, IP TV Applications Internet Access VPLS/VPLAN Basic Telephony (SIP) Cable TV, IP TV ONT Types & Applications
FTTH in Gujarat • Ahmedabad • Gandhinagar • Mehsana • Vadodara • Surat • Anand • Bharuch • Dahej • OLT -61 AM • OLT- 88 GUJ
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