Overview of PON Network

PON has now became a popular network technology all over the globe. It first came in to being in 1995. The International Telecommunication Union (ITU) standardized two initial generations of PON – APON and BPON. And the advancement of PON network has never stopped. Until now, the recent PON standard of NG-PON2 has been put forward in 2015. With the maturity of PON, people are more easily accessible to networks today. But what does PON exactly mean? What’s the composition of PON network? The following part will give you the answer.

PON, also known as passive optical network, is a technology in telecommunication that implements a point-to-multipoint (P2MP) architecture. Unpowered fiber optic splitters are used to enable a single optical fiber to serve multiple end-points such as customers instead of providing individual fibers between the central office (hub) and customer. According to different terminations of PON, the network system can be divided into fiber-to-the-home (FTTH), fiber-to-the-curb (FTTC), fiber-to-the-curb (FTTB), etc. To be specific, a PON is made up of an optical line terminal (OLT) at the service provider’s hub and a number of optical network units (ONUs) or optical network terminals (ONTs) near end users. And “passive” is just used to describe that no power requirement or active electronic component is included for transmitting signals in the system.

PON network

Types of PON Network

Here are some types of PON that have been used throughout the years:

1) APON

Its full name is asynchronous transfer mode (ATM) passive optical network. As the original PON system, APON uses ATM technology to transfer data in packets or cells of a fixed size. In APON, downstream transmission is a continuous ATM stream at a bit rate of 155 Mbps or 622 Mbps. Upstream transmission is in the form of bursts of ATM cells at 155 Mbps.

2) BPON

BPON, also known as broadband PON, is the improved version of APON. It adopts wavelength division multiplexing (WDM) for downstream transmission with the transmission rate up to 622 Mbps. It also provides multiple broadband services such as ATM, Ethernet access and video distribution. Today, BPON is more popular than APON.

3) EPON

EPON or Ethernet PON uses the Ethernet packets instead of ATM cells. Upstream and downstream rates of EPON are able to achieve up to 10 Gbps. It is now widely applied to FTTP or FTTH architecture to serve multiple users. With the advantages of scalability, simplicity, multicast convenience and capability of providing full service access, many Asian areas adopt EPON for their networks.

4) GPON

Gigabit PON is the development of BPON. It supports various transmission rates with the same protocol. The maximum data rate of downstream is 2.5 Gbps and upstream is 1.25 Gbps. It is also widely used for FTTH networks. But compared with EPON, its burst sizes and physical layer overhead are smaller.

Advantages of PON

  • Low cost, simple maintenance, flexible extensibility and easy to upgrade. And no need for power during transmission saves a lot for long-term management.
  • Using pure media network avoids the interference of lightning and electromagnetism. Thus PON network is suitable for areas under harsh conditions.
  • Low occupancy of central office resources, low initial investment and high rate of return.
  • As the P2MP network, PON is able to provide a large range of service to plenty of users.

Conclusion

PON network is for sure an effective solution for multiple network users. EPON and GPON are the most commonly deployed PON systems at present. Since people have been seeking for higher bandwidth provisioning, the capability of transmission will be greatly improved in the near future.

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Comparison Between EPON and GPON

PON is the abbreviation of passive optical network, which only uses fiber and passive components like fiber splitter and combiner. EPON (Ethernet PON) and GPON (Gigabit PON) are the most important versions of passive optical networks, widely used for Internet access, voice over Internet protocol (VoIP), and digital TV delivery in metropolitan areas. Today we are going to talk about the differences between EPON and GPON.

PON network(EPON and GPON)

Technology Comparison of EPON and GPON

EPON is based on the Ethernet standard 802.3 that can support the speed of 1.25 Gbit/s in both the downstream and upstream directions. It is well-known as the solution for the “first mile” optical access network. While GPON, based on Gigabit technology, is designated as ITU-T G.983 which can provide for 622 Mbit/s downstream and 155 Mbit/s upstream. GPON is an important approach to enable full service access network. Its requirements were set force by the Full Service Access Network (FASN) group, which was later adopted by ITU-T as the G.984.x standards–an addition to ITU-T recommendation, G.983, which details broadband PON (BPON).

As the parts of PON, they have something in common. For example, they both can be accepted as international standards, cover the same network topology methods and FTTx applications, and use WDM (wavelength-division multiplexing) with the same optical frequencies as each other with a third party wavelength; and provide triple-play, Internet Protocol TV (IPTV) and cable TV (CATV) video services.

Costs Comparison

No matter in a GPON or in an EPON, the optical line terminal (OLT), optical network unit (ONU) and optical distribution network (ODN) are the indispensable parts, which are the decisive factor of the costs of GPON and EPON deployments.

The cost of OLT and ONT is influenced by the ASIC (application specific integrated circuit) and optic module. Recently, the chipsets of GPON are mostly based on FPGA (field-programmable gate array), which is more expensive than the EPON MAC layer ASIC. On the other hand, the optic module’s price of GPON is also higher than EPON’s. When GPON reaches deployment stage, the estimated cost of a GPON OLT is 1.5 to 2 times higher than an EPON OLT, and the estimated cost of a GPON ONT will be 1.2 to 1.5 times higher than an EPON ONT.

We all know that the ODN is made up of fiber cable, cabinet, optical splitter, connector, and etc. In the case of transmitting signals to the same number of users, the cost of EPON and GPON would be the same.

Summary

Nowadays, since many experts have different opinions on EPON and GPON. Thus, there is no absolute answer to determine which is better. But one thing is clear: PON, which possesses the low cost of passive components, has made great strides driven by the growing demand for faster Internet service and more video. Also, fiber deployments will continue expanding at the expense of copper, as consumer demands for “triple-play” (video, voice and data) grow.

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EPON VS GPON

A passive optical network (PON) is a fiber network that only uses fiber and passive components like fiber splitters and combiners. It starts from the optical line terminal (OLT) in the central office and ends at the optical network unit (ONU) at the customer’s home (as shown in the following figure). Today, we’ll talk about EPON vs GPON.

PON

EPON vs GPON: What Are the Difference?

Ethernet passive optical network (EPON) and gigabit passive optical network (GPON) are two popular versions of PONs. The most dramatic distinction between EPON and GPON is a marked difference in architectural approach. EPON employs a single Layer 2 network that uses Internet Protocol (IP) to carry data, voice, and video. While GPON provides three Layer 2 networks: ATM for voice, Ethernet for data and proprietary encapsulation for voice. Moreover, they also vary from each other in terms of bandwidth, per-subscriber cost, efficiency, management system and encryption.

  • Usable Bandwidth

EPON generally delivers 1 Gbit/s symmetrical bandwidth. And its Gigabit Ethernet service actually constitutes 1 Gbit/s of bandwidth for data and 250 Mbit/s of bandwidth for encoding. GPON, however, promises 1.25 Gbit/s or 2.5 Gbit/s downstream and upstream bandwidths scalable from 155 Mbit/s to 2.5 Gbit/s.

  • Per-subscriber Costs

EPON lowers the costs of subscribers by allowing carriers to simplify their networks and to eliminate complex and expensive asynchronous transfer mode (ATM). While the costs of EPON equipment are approximately 10 percent of the costs of GPON equipment.

  • Efficiency

According to the IEEE 802.3 protocol for Ethernet, data transmission occurs in variable-length packets of up to 1518 bytes in EPON. The use of variable-length packets makes Ethernet to carry IP traffic, which significantly reduces the overhead relative to ATM.

In GPON, data transmission occurs in fixed-length 53 byte cells as specified by the ATM protocol. This format makes it inefficient for GPON to carry traffic formatted according to IP, which calls for data to be segmented into variable-length packets of up to 65,535 bytes. This process is time-consuming and complicated.

  • Management systems

EPON requires one single management system, which means EPON results in a significantly lower total cost of ownership. In addition, it does not require multi-protocol conversions, and the result is a lower cost of silicon. In GPON, there are three management systems for the three Layer protocols. Thus it is more expensive. Furthermore, GPON does not support multi-cast services. This makes support for IP video more bandwidth-consuming.

  • Encryption

EPON uses an advanced encryption standard (AES) based mechanism, which is supported by multiple silicon vendors and deployed in the field. Furthermore, EPON encryption is both downstream and upstream. While the encryption in the GPON is part of the International Telecommunication Union (ITU) standard and GPON encryption is downstream only.

Conclusion

All in all, when EPON vs GPON, both have their advantages and disadvantages. It is hard to say which one will be prevailing. But one thing is clear: PON deployment will continue expanding. FS launches a series of integrated, high reliability and affordable EPON/GPON system solutions for its customers to meet the fast growing demand of PON deployment. In addition, network equipment like network switch, transceiver module also are available at FS.

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