What is Passive Optical Network (PON)? Everything You Need To Know

Many readers enjoy a PON-based fast network at home but may need to learn more about it. This post focuses on the PON topics and shares everything with our valued readers. This complete guide will help you know more about it.

Without further ado, let’s get started.

Table of Contents

What is PON?
Types of PON
PON Components
Benefits of PON
Limitations of PON
FAQs

What is PON?

PON is a passive optical network that uses point-to-multipoint (P2MP) topology and optical splitters to send data from a single source to multiple user terminals. In this instance, “passive” refers to the unpowered state of the fiber and splitting/combining components.

Unlike active optical networks (AON), passive optical networks require power only at the transmit and receive points. Still, the optical transmission has no power requirement once the signal is transmitted across the network, which allows PONs to achieve significant system cost savings.

Different Types of PON

PON technology has evolved since its inception in the 1990s. PON technology has undergone several stages. Next, let us quick a look at those terms:

APON (155Mbps down / 155Mbps up): Short for Asynchronous Transfer Mode (ATM) Passive Optical Network. It is the oldest PON technology. ATM is a cell-based transmission protocol. It can provide dynamic bandwidth allocation for the access network.
BPON (622Mbps down / 155Mbps up): Short for Broadband Passive Optical Network. It is based on APON but with an enhanced transmission rate of 622Mbps. Simultaneously, it offers dynamic bandwidth allocation, protection, and other capabilities, as well as the ability to give Ethernet access, video transmission, high-speed leased lines, and other services.
EPON (1.25G down / 1.25G up): Short for Ethernet Passive Optical Network. Proposed by the IEEE 802.3 standard, it is seamlessly compatible with Ethernet network equipment. Traditional EPON can support symmetrical upstream and downstream speeds of up to 1.25 Gbps.
10G-EPON (10G down / 10G up, 10G down / 1.25G up): Short for 10G Ethernet Passive Optical Network. Two types are available: symmetric (10 Gbps for both directions) and asymmetric (10 Gbps downstream and 1.25 Gbps upstream).
GPON (2.5G down / 2.5G up): Short for Gigabit Passive Optical Network, It supports a high speed of 2.5 Gbps. Encoding in GPON is done via IP and ATM or the GPON encapsulation method (GEM).
XG-PON (10G down / 2.5G up): XG-PON is simply a faster variant of GPON. It has the same characteristics as GPON and can share the same fiber. XG-PON has yet to see deployment to date.
XGS-PON (10G down / 10G up): XGS-PON is a symmetric, greater bandwidth (4x faster) version of GPON. It has the same characteristics as GPON and can coexist on the same fiber.
NG-PON2 (10G down / 10G up, 10G down / 2.5G up): NG-PON2 is not simply a greater bandwidth version of GPON but also allows for new characteristics such as wavelength mobility and channel bonding. NG-PON2 works well alongside GPON, XG-PON, and XGS-PON.
25G-PON (25G down / 10G or 25G up): Including asymmetric and symmetric types, it is suitable for residential, business, mobile back/mid-haul, and other fiber optic applications. It is possible to coexist with 25GS-PON, G-PON, XG-PON, XGS-PON, and NG-PON2.
50G-PON (50G down / 10G or 25G or 50G up): The next PON standard with 50G downstream speed, which will serve several real 10G services, 5G fronthaul, and residential services over a single fiber. This standard has been released, but suppliers must develop the necessary chips and products first.

PON Components

Optical Line Terminal: Also known as OLT, it is the heart of a passive optical network and serves as the entry point. Its main job is to convert the FiOS service provider’s standard signals to the PON system’s frequency and frame, as well as coordinate the conversion hardware’s multiplexing on optical network terminals (ONTs). As a core sector in the PON network, its price is much higher than ONT. Take the GPON as an example, the GPON OLT price is $59.0, while the GPON ONT is $35.0.
Optical Network Terminal: Also known as ONT, but sometimes called ONU, it is a specialized modem that converts optical signals into electrical signals at the end user. Therefore, it supports broadband access for devices such as WiFi, TVs, desktops, etc. The ONT also sends aggregated and optimized data back to the OLT from end users.
Fiber Optic Splitter: in the PON network, an optical splitter is crucial to split one Point to Multi-Point (P2MP) physical fiber network. By connecting with OLT and ONT, the fiber splitter may achieve split ratios of 1:2, 1:4, 1:8, 1:16, 1:32, and more.

Benefits of PON

Low Total Cost: PON is a cost-effective technology. Because PON technology uses a single fiber to support multiple users (point-to-multipoint), it is less costly in infrastructure and material costs than active point-to-point systems.
Reliable Performance: Using fiber optic technology, PON is more reliable than other technologies. One reason is that fiber optic cabling is smaller, lighter, and more flexible than other types of cabling, making it easier to move through homes and buildings.
Ease of Maintenance: Compared with traditional copper networks, PON networks are less susceptible to electromagnetic interference and noise. As a result, signal integrity is well maintained over the planned distance. Because faults on PON elements (OLT, ONT, Fiber Splliter) are easy to see and identify, these networks are easier to maintain and troubleshoot.
Efficient Use of Power: Due to the decreased power required in the PON network, there are fewer maintenance tasks and chances for powered equipment failures.
Flexible and scalable: PON’s point-to-multipoint structure is a massive advantage if you’re a business owner. Because it provides the best flexibility and scalability, as your business and network grow, you’ll get the support you need for changing bandwidth needs.

Limitations of PON

Although the passive optical network provides many benefits, it still has some limitations. Let us quick a look at them.

Distance: Unlike active optical networks, passive optical networks may have disadvantages despite their many advantages. An active optical network can range up to 120 km, but PON can only be 20 to 40 km. That limit its usage in some application that requires long distance.
Diagnostic Challenge: The ONT (home equipment) may be unplugged when a technician needs to do a diagnostic. Moreover, a piece of faulty equipment could impair the operation of a portion of the entire PON, affecting several clients.
Time-consuming: compared with point-to-point (P2P) active networks, passive optical networks require more time on splitters locations designed to provide optimal system.

What Is a Passive Optical LAN (POL)

Passive Optical Local Area Network, or POL for short, is a novel PON-based LAN networking solution. Using fiber optic and P2MP, POL can carry TV, telephone, and Internet access services to up to 32 end users through a single central point (OLT). Optical LAN is a future-proof, high-capacity always-on network for indoor and campus connectivity and mobile backhaul. It can cover up to 20 kilometers without telecommunications rooms, switches, and power every 100 meters.

FAQs

Q: What is the maximum speed of PON?

A: It depends. Different PON technology supports different speeds. Take an example, GPON supports 2.5Gbps, while the XGS-PON support 10Gbps. At present, the maximum speed is 50Gbps for 50G-PON.

Q: What is the difference between PON and GPON?

A: GPON is one of the specific passive optical networks belonging to PON. The typical data rate is 2.5Gbps.

Q: Is an ONT required to power supply?

A: You should keep your ONT powered for the correct function, so don’t turn it off.

Q: How can I link my PON ONT to the WIFI router?

A: Generally speaking, you may link the ONT to the WIFI router through an Ethernet cable.

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Networking Device, Optical Networking, Optical Transceiver