This document discusses different types of network connections and fiber optic technologies used for broadband access. It explains the differences between a hub, switch, and point-to-point vs point-to-multipoint connections. The document also provides details on Fiber To The X (FTTX) networks, including that optical network terminals (ONTs) or optical network units (ONUs) are used at customer premises to convert optical signals to electrical formats. Finally, it compares active optical networks (AONs) and passive optical networks (PONs), describing their components like the optical line terminal (OLT) and advantages/disadvantages of each type.

2. TOPICS TO BE DISCUSSED

3. TYPES OF CONNECTION
1.Point to Point Connection
2.Point to Multi-Point Connection

4. Point to Point Connection
A
Point to Point Connection
B
• Difference between HUB and SWITCH…?

5. • HUB provides a point-to-multipoint (or
simply multipoint) circuit. which divides the
total bandwidth to all connected client
node.
• SWITCH on the other hand provides a
series of point-to-point circuits, which
allows each client node to have a
dedicated circuit and the added advantage
of having full-duplex connections.

7. FTTX

8. Something more about FTTX….!!
• At each customer's premises is a special type of
network interface device (NID). This device is called
either an optical network terminal (ONT) or an optical
network unit (ONU).
• It converts the optical signal into some format
understandable to the customer's devices.
• Optical network units use thin film filter technology to
convert between optical and electrical signals.
• The connection between the optical network terminal at
the customer's premises and the equipment at the
provider's central office is called an optical distribution
network (ODN).

10. Network interface device (NID)
• This device is also called as either an optical network
terminal (ONT) or an optical network unit (ONU).
• It converts the optical signal into some format
understandable to the customer's devices.
• Optical network units use thin film filter technology to
convert between optical and electrical signals.
• The connection between the optical network terminal at
the customer's premises and the equipment at the
provider's central office is called an optical distribution
network (ODN).

11. •The simplest optical distribution network is called home run fiber. In this
architecture, each fiber leaving the central office goes to exactly one
customer.
Such networks can provide excellent bandwidth since each customer gets
their own dedicated fiber extending all the way to the central office.
However, this approach is extremely costly due to the amount of fiber
and central office machinery required. It is usually used only in instances
where the service area is very small and close to the central office.
More commonly each fiber leaving the central office is actually shared by
many customers. So we need proper optical distribution network to split
individual customer-specific fibers.
There are two competing optical distribution network architectures
which achieve this split: active optical networks (AONs) and passive
optical networks (PONs).

12. Active Optical Network
• Active optical networks rely on some sort of electrically
powered equipment to distribute the signal, such as a
switch, router, or multiplexer.
• Each signal leaving the central office is directed only to
the customer for which it is intended.(point-to-point
network structure)
• Incoming signals from the customers avoid colliding at
the intersection because the powered equipment there
provides buffering.
• Such networks are identical to Ethernet computer
networks used in businesses and academic institutions,
except that here purpose is to connect homes and
buildings to a central office rather than to connect
computers and printers within a location. Each switching
cabinet can handle up to 1,000 customers

14. Passive Optical Network
• In comparison with active optical networks, passive optical
networks have significant advantages and disadvantages.
They avoid the complexities involved in keeping electronic
equipment operating outdoors.
• They also allow for analog broadcasts
• However, because each signal must be pushed out to
everyone served by the beam splitter (rather than to just a
single switching device), the central office must be
equipped with a particularly powerful piece of transmitting
equipment called an optical line terminal (OLT).

15. Optical Line Terminal
• It is a device which serves as the service provider end
point of a passive optical network. It provides two main
functions:
1. to perform conversion between the electrical signals
used by the service provider's equipment and the fiber
optic signals used by the passive optical network.
2. to coordinate the multiplexing between the conversion
devices on the other end of that network (called either
optical network terminals or optical network units).

16. • An OLT, in a nutsell, is where the PON cards reside. The OLT's also
contain the CPU and the GWR and VGW uplink cards. Each OLT
can have a few or many dozens of PON cards.
PON = Passive Optical Network
GWR = Gateway Router
VGW = Voice Gateway
Each OLT vendor has different models and configurations,
depending on the technology and the end-user.

17. Location of OLT and ONT in
N/W

19. Advantages of PONs
• Conserves fiber resources
• Low cost of equipment per subscriber
• There is only one optical port at the Central Office
(instead of multiple ports)
• Passive components require little maintenance.
• Additional buildings can be added to the network easily
and inexpensively
• Supports a broad range of applications including triple
play (voice, data, video) over a single fiber and FTTB,
FTTC, FTTH
• Offers a large amount of high speed bandwidth providing
greater flexibility for adding future services
• Flexible and scalable bandwidth assignment

20. Disadvantages of PONs
•
•
•
•
Fixed location install only
Optical fiber price still higher than copper
Require installed extra splitter when network spread
Splitter and bandwidth ratio cause the network size be
limited
• Bandwidth is limited on OLT capability
• Shared bandwidth network topology
• QoS issues

22. REFFERENCES
• White paper AON vs PON published by
KEYMILE International GmbH. (2008)