basics of optical network architecture, pon & gpon

Optical Fiber Communication

Syed Shujat Ali 1421-311065M Masoud Ahmad 1421-211016

Numan Ahmad Naseer 1421-211

Contents• Architecture Of Optical Access Network• PON• GPON

Optical Network AccessFrom the architecture diagram, the optical access network comprises the following scenarios:1. FTTB scenario2. FTTC & FTTCab scenario3. FTTH scenario

1- FTTB Scenario• Fiber to the Building , is the deployment of fiber (optical)

cable to a specific location within a building, then connected to the buildings existing copper cable facilities.

• This deployment is also referred to as :i. FTTB (Fiber to the Basement)ii. FTTB (Fiber to the Business).• This deployment will be the typical for MTU’s.i. MTU :Business Multi-tenant unit ; providing a comparatively larger number

of ports, including POTS, 10/100/1000BASE-T and DS1/T1/E1 ports.

2-FTTC & FTTCab scenario• Fiber to the Curb , is the deployment of fiber close

to the customer but not fully to the customers residence.

i. MDU : Multi-dwelling unit ;providing a comparatively larger number of ports, including 10/100/1000BASE-T, VDSL2, and so on.

• In this deployment the existing copper plant is still used to deliver service to the actual customer.

• Following Scenarios Also Falls Under This Categoryi. FTTN (Fiber to the Neighborhood)ii. FTTC (Fiber to the Cabinet)

3-FTTH scenario• Fiber to the Home is the complete deployment

of fiber to the customers home, with replacement of there existing NID (Network Interface Device).

i. SFU : Single family unit , providing a comparatively small number of ports, including following types: POTS, 10/100/1000BASE-T, and RF.

• This replacement device is called an ONT (Optical Network Terminator).

i. The ONT converts fiber-optic light signals to copper/electric signals.

PON (Passive Optical Network)

• A passive optical network (PON) is a point-to-multipoint, fiber to the premises (FTTP) network architecture in which unpowered optical splitters are used to enable a single optical fiber to serve multiple premises

• In Simple it uses passive optical splitters to serve many subscribers from one optical unit

•  A PON consists ofi. Optical Line Terminal (OLT) at the Central Office (CO) ii. Number of Optical Network Terminals (ONTs)at customer premises

PON (Passive Optical Network)

8 Reasons Of Why To Use PON

• Enormous information carrying capacity• Easily upgradeable• Ease of installation• Reduced O&M costs• Long distance reach• Secure• Immune to electromagnetic noise• Best suited for triple play services

GPON(Gigabit Passive Optical Network)

• Evolutionary technology based upon BPON(Broadband passive optical network).

• It supports higher rates, enhanced security, and choice of Layer 2 protocol (ATM, GEM, Ethernet).

• GPON uses IP-based protocols to transfer data.

Transmission Speed Combo(s) In GPON

Advantages/Features Of GPON

• Standardized by ITU-T G.984 .• Operates at 2.488 Gbps downstream and 1.244 Gbps

upstream.• Practical fiber split ratios up to 1:64 (standard supports up to

1:128)• Distance between OLT and ONT/ONU can be up to 20 km.• GPON specifies QoS and management protocols required for

triple-play services over the network.• Downstream security guaranteed with 128-bit AES encryption.• Reduced equipment and fiber at the central office

Data Multiplexing In GPON• GPON adopts Wavelength Division Multiplexing

(WDM) technology, facilitating bi-direction communication over a single fiber.

1490nm

1310nm

Data Multiplexing in GPON• To separate upstream/downstream signals of

multiple users over a single fiber• GPON adopts two multiplexing mechanisms:i. In downstream direction, data packets are transmitted in a

broadcast manner;ii. In upstream direction, data packets are transmitted in a TDMA

manner.

Down streaming in GPON• Line rate.i. Downstream : 2.488 Gb/sii. Upstream : 1.244 Gb/s.• Broadcast modei. Continuous mode operation.ii. Traffic in the downstream is sent to/received by every ONU. • Issuei. Data confidentialityii. AES-Advanced Encryption Standard used for link layer

encryption.

Down streaming in GPON

Up streaming In GPON• TDMA(Time Division Multiple Access)i. Burst mode operation.ii. The OLT controls which ONU gets access to the upstream at a

particular moment in time.• Concernsi. Potential collisionii. Access granting.iii. Distance ranging.

Up streaming In GPON