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VAINAVI
Connecting to the world
Company Profile
VAINAVI INDUSTRIES LIMITED is a class “B” Internet Service
Provider licensed by the Department of telecommunications, Govt.
of India. We provide next generation broadband services that enable
fast, simple and reliable communications, anytime, anywhere within
our coverage area. Our unique, advanced network not only creates a
new communications path into the home or office, but also facilitates
access to information, interactive media content, applications and
communications services away from the home or office. We also
carry out the business of providing infrastructure for broadband and
telecom Sector by facilitating them to carry Voice, Video & other
forms of data.
Vainavi Industries Limited
(Class B ISP License Holder)
Vision Infracon Pvt. Ltd
(Underground Fiber Company
IP 1 License Holder)
Sun Constructions
(Over Head Fiber Company)
Why Fiber
Today’s high data rate networks are all based on optical fiber
the reason is simple (examples for demonstration sake)
Twisted copper pair(s)
8 Mbps @ 3 km, 1.5 Mbps @ 5.5 km (ADSL)
1 Gb @ 100 meters (802.3ab)
Microwave
70 Mbps @ 30 km (WiMax)
Coax
10 Mbps @ 3.6 km (10BROAD36)
30 Mbps @ 30 km (cable modem)
Optical fiber
10 Mbps @ 2 km (10BASE-FL)
100 Mbps @ 400m (100BASE-FX)
1 Gbps @ 2km (1000BASE-LX)
10 Gbps @ 40 (80) km (10GBASE-E(Z)R)
40 Gbps @ 700 km [Nortel] or 3000 km [Verizon]
Why is fiber better
Attenuation per unit length
Reason for energy loss
copper: resistance, skin effect, radiation, coupling
fiber: internal scattering, imperfect total internal reflection
so fiber beats coax by about 2 orders of magnitude
e.g. 10 dB/km for thin coax at 50MHz, 0.15 dB/km l =1550nm fiber
Noise ingress and cross-talk
Copper couples to all nearby conductors
No similar ingress mechanism for fiber
Ground-potential, galvanic isolation, lightning protection
Copper can be hard to handle and dangerous
No concerns for fiber
Why not fiber
Fiber beats all other technologies for speed and reach
But fiber has its own problems
• Harder to splice, repair, and need to handle carefully
• Regenerators and even amplifiers are problematic
More expensive to deploy than for copper
• Digital processing requires electronics
So need to convert back to electronics
We will call the converter an optical transceiver
Optical transceivers are expensive
• Switching easier with electronics (but possible with photonics)
So pure fiber networks are topologically limited:
• Point-to-point
• Rings
Gpon Solution
Implement point-to-multipoint topology purely in optics
 avoid costly optic-electronic conversions
 use passive splitters – no power needed, unlimited
MTBF
 only N+1 optical transceivers (minimum possible) !
access network
1:2 passive splitter
N end users
core
typically N=32
feeder fiber
1:4 passive splitter
max defined 128
Gpon Advantages
Shared infrastructure translates to lower cost per customer
• Minimal number of optical transceivers
• Feeder fiber and transceiver costs divided by N customers
• Greenfield per-customer cost similar to UTP
Passive splitters translate to lower cost
• Can be installed anywhere
• No power needed
• Essentially unlimited MTBF (Mean Time Between Failures)
Fiber data-rates can be upgraded as technology improves
• Initially 155 Mbps
• Then 622 Mbps
• Now 1.25 Gbps
• Soon 2.5 Gbps and higher
Terminology
Like every other field, PON technology has its own terminology

The CO head-end is called an OLT

ONUs are the CPE devices (sometimes called ONTs in ITU)

The entire fiber tree (incl. feeder, splitters, distribution fibers) is an
ODN

All trees emanating from the same OLT form an OAN

Downstream is from OLT to ONU (upstream is the opposite
direction)
downstream
upstream
NNI
Optical Distribution Network
cor
e
Optical Network Units
splitter
Optical Line Terminal
Optical Access Network
UNI
Terminal
Equipment
GPON Principles
GPON obey the basic principles
OLT and ONU consist of
•Layer 2 (Ethernet MAC, ATM adapter, etc.)
•optical transceiver using different ls for transmit and receive
•optionally: Wavelength Division Multiplexer
Downstream transmission
•OLT broadcasts data downstream to all ONUs in ODN
•ONU captures data destined for its address, discards all other data
•encryption needed to ensure privacy
Upstream transmission
•ONUs share bandwidth using Time Division Multiple Access
•OLT manages the ONU timeslots
•ranging is performed to determine ONU-OLT propagation time
Additional functionality
•Physical Layer OAM (Operation, Administration, & Maintenance)
•Autodiscovery
•Dynamic Bandwidth Allocation
Why a new protocol ?
downstream
GPON has a unique architecture
upstream
• (broadcast) point-to-multipoint in DS direction
• (multiple access) multipoint-to-point in US direction
contrast that with, for example
• Ethernet - multipoint-to-multipoint
• ATM(Asynchronous Transfer Mode) - point-to-point
This means that existing protocols
do not provide all the needed functionality
e.g. receive filtering, ranging, security, BW allocation
(multi)point - to - (multi)point
Multipoint-to-multipoint Ethernet avoids collisions
by CSMA/CD (Carrier Sense Multiple Access)/ (Collision Detection) )
This can't work for multipoint-to-point US GPON
since ONUs don't see each other
And the OLT can't arbitrate without adding a roundtrip time
Point-to-point ATM can send data in the open
although trusted intermediate switches see all data
customer switches only receive their own data
This can't work for point-to-multipoint DS GPON
since all ONUs see all DS data
GPON history
2001 : FSAN initiated work on extension of BPON to > 1 Gbps
Although GPON is an extension of BPON technology
and reuses much of G.983 (e.g. line code, rates, band-plan, OAM)
decision was not to be backward compatible with BPON
2001 : GFP developed (approved 2003)
2003 : GPON became G.984
G.984.1 : GPON general characteristics
G.984.2 : Physical Media Dependent layer
G.984.3 : Transmission Convergence layer
G.984.4 : management and control interface
FSAN is Full Service Access Network
BPON is Broadband Passive Optical Network
Types of Optical Fiber
Popular Fiber Sizes
Multimode Graded-Index Fiber
Single-mode Fiber
Multimode Dispersion
1
0
1
1
Dispersion limits bandwidth in optical fiber
1
1
Single-Mode Dispersion
1
0
11
1
0
1
In SM the limit bandwidth is caused by chromatic dispersion.
Optical Splitters
Budget Calculations
LB
=
‫׀‬P ‫׀‬-‫׀‬P ‫׀‬
S
O
LB = Link Budget
PS = Sensitivity
PO = Output Power
Example: GPON 1310nm
Power: 0dbm Single-mode fiber
Sensitivity: -23dbm
}
Link Budget: 23db
Typical Range Calculation
Assume:
Optical loss = 0.35 db/km
Connector Loss = 2dB
Splitter Insertion Loss 1X32 = 17dB
Range Budget: 11Km
Relationship between transmission distance and number of splits
GPON Encapsulation Mode
A common complaint against BPON was inefficiency due to ATM cell tax
GEM is similar to ATM
constant-size HEC-protected header
but avoids large overhead by allowing variable length frames
GEM is generic – any packet type (and even TDM) supported
GEM supports fragmentation and reassembly
GEM is based on GFP, and the header contains the following fields:
Payload Length Indicator - payload length in Bytes
Port ID - identifies the target ONU
Payload Type Indicator (GEM OAM, congestion/fragmentation indication)
Header Error Correction field (BCH(39,12,2) code+ 1b even parity)
The GEM header is XOR'ed with B6AB31E055 before transmission
GEM (Generic Encapsulation Mode) GFP (Generic Frame Protocol)
PLI
(12b)
Port ID
(12b)
5B
PTI
(3b)
HEC
(13b)
payload fragment
(L Bytes)
GPON US considerations
GTC fames are still 125 msec long, but shared amongst ONUs
Each ONU transmits a burst of data
– using timing acquired by locking onto OLT signal
– according to time allocation sent by OLT in BWmap
• there may be multiple allocations to single ONU
• OLT computes DBA by monitoring traffic status (buffers)
of ONUs and knowing priorities
– at power level requested by OLT (3 levels)
• this enables OLT to use avalanche photodiodes which are
sensitive to high power bursts
– leaving a guard time from previous ONU's transmission
– prefixing a preamble to enable OLT to acquire power and phase
– identifying itself (ONU-ID) in addition to traffic IDs (VPI, Port-ID)
– scrambling data (but not preamble/delimiter)
GPON Auto discovery
Every ONU has an 8B serial number (4B vendor code + 4B SN)
 SN of ONUs in OAN may be configured by NMS, or
 SN may be learnt from ONU in discovery phase
ONU activation may be triggered by
 Operator command
 Periodic polling by OLT
 OLT searching for previously operational ONU
G.984.3 differentiates between three cases:
 cold GPON / cold ONU
 warm GPON / cold ONU
 warm GPON / warm ONU
Main steps in procedure:
 ONU sets power based on DS message
 OLT sends a Serial_Number request to all unregistered ONUs
 ONU responds
 OLT assigns 1B ONU-ID and sends to ONU
 ranging is performed
 ONU is operational
Failure recovery
GPONs must be able to handle various failure states
GPON
If ONU detects LOS or LOF it goes into POPUP
state
it stops sending traffic US
OLT detects LOS for ONU
if there is a pre-ranged backup fiber then
switch-over
Dynamic Bandwidth Allocation
MANs and WANs have relatively stationary BW requirements
due to aggregation of large number of sources
But each ONU in a GPON may serve only 1 or a small number of
users
So BW required is highly variable
It would be inefficient to statically assign the same BW to each ONU
So GPON assign dynamically BW according to need
The need can be discovered
– by passively observing the traffic from the ONU
– by ONU sending reports as to state of its ingress queues
The goals of a Dynamic Bandwidth Allocation algorithm are
– maximum fiber BW utilization
– fairness and respect of priority
– minimum delay introduced
GPON With Triple Play Offer on FTTH Technology
SURF
TALK
WATCH
What is triple Play
One of the hottest trends in consumer telecom
services is called the “residential triple play.”
This is a bundling that combines three electronic
services that nearly every home subscribes to.
They are Digital CATV, telephony and High
Speed Internet.
CABLE TV
INTERNET
TELEPHONY
Advantages of Triple Play











To provide technically efficient & Cost effective
Triple Play Service through GPON FTTH
Adds Value to the amenities
Seamless Network
Eliminates cable clutter & Jammed ducts
Intercom & security systems
One point of contact for all kind of services
Easy up gradation to future technologies
Expandable network
Easy maintenance
No electric power within network
Typical Connectivity Diagram
HAS
STB
Up to ~ 10+ km
CATV
OLT_1U_PB_2608
PC
VOIP
SP1-Video/
Data
WLAN
64 waySplitter
WDM
SP2-Video/
Data
IPTV
1310 & 1490 nm
SP3-Video/
Data
HAS
VOIP
Laptop
HAS
SP5
SP4
TDM
Interface
STB
CATV
VOIP
Opti
cal
TX
Ampli
fier
WDM
64 waySplitter
IPTV
Ampli
fier
HAS
VOIP
Laptop
GPON on FTTB Technology ONT On Sharing
GPON on FTTH Technology ONT at Individual House
VAINAVI
THANK YOU