XGS-PON vs GPON vs EPON for Data Center Connectivity

Data centers are the backbone of our digital world, demanding ever-increasing bandwidth and scalability to support the growing demands of cloud computing, big data analytics, and high-performance computing. As data centers evolve, so too must the technology that underpins them.

Traditional PON technologies, such as GPON and EPON, have served data centers well, but their limitations in bandwidth and scalability are becoming increasingly apparent. XGS-PON, offers a significant leap forward, addressing these limitations and paving the way for a future-proof data center infrastructure.

XGS-PON (10G Symmetrical Passive Optical Network) delivers 10 Gbps symmetrical bandwidth over a single fiber, a substantial improvement over the 2.5 Gbps downstream and 1.25 Gbps upstream offered by GPON and the 1 Gbps symmetrical offered by EPON. This high bandwidth enables data centers to handle the demanding traffic generated by modern applications, ensuring seamless operation and optimal performance.

Beyond bandwidth, XGS-PON also offers significant advantages in scalability. Its higher bandwidth allows for a larger number of ONTs (Optical Network Terminals) per OLT (Optical Line Terminal), supporting the expansion of data center infrastructure as demands grow. XGS-PON's scalability also translates to reduced operational costs by minimizing the need for multiple OLTs and reducing cabling complexity.

Here's a detailed comparison:

Why XGS-PON is the Right Choice for Data Centers:

• Unmatched Bandwidth: XGS-PON's 10 Gbps symmetrical bandwidth caters to the demanding bandwidth requirements of modern data center applications.
• Enhanced Scalability: XGS-PON allows for a larger number of ONTs per OLT, making it ideal for the dynamic and evolving nature of data centers.
• Lower Latency: XGS-PON's high bandwidth and optimized protocols contribute to lower latency, which is crucial for real-time applications and data-intensive workloads.
• Future-Proof Investment: XGS-PON provides a future-proof investment, ensuring that data center infrastructure can meet the demands of future applications.

GLSUN is a leading provider of XGS-PON solutions, offering a wide range of high-quality products designed to meet the unique requirements of data centers. Our 10G XGSPON ONU is a perfect example of our commitment to delivering cutting-edge technology for data center connectivity.

What is GPON?

Passive Optical Network (PON) technology has become one of the mainstream technologies for Fiber-to-the-X (FTTx) network construction. As users' demand for high bandwidth continues to grow, especially with the popularization of high-traffic applications such as OTT video and 4K TV, operators have included 10G GPON technology in their schedules to meet users' urgent need for faster and more reliable network connections. GPON is generally divided into GPON, XG-PON and XGS-PON.

Gigabit Passive Optical Network (GPON) is an optical fiber transmission technology that uses a single optical fiber line to transmit data to achieve high-speed, high-bandwidth network connections. The basic principles of GPON involve light transmission and the use of optical splitters. In the GPON network, an optical fiber line connects multiple users and distributes signals to different end users through optical splitters to achieve data transmission.

The architecture of GPON includes optical line terminal (OLT) and optical network unit (ONU). The OLT is responsible for communicating with the ONU on the user side, and the ONU is responsible for communicating with the user equipment. This distributed structure enables the GPON system to support a large number of users and be widely used in different fields.

1. GPON Technical Specifications

Among the technical specifications of GPON, one of the most prominent features is its high bandwidth requirements. GPON is typically capable of providing transmission rates of 1.25 Gbps (downstream direction) and 2.5 Gbps (upstream direction). This high bandwidth makes GPON excellent in supporting high-traffic applications such as high-definition video and large-capacity file transfer.

In addition, GPON also has certain advantages in distance. Fiber optic transmission allows signal transmission distances to reach tens of kilometers, which enables GPON to meet a wide range of network topology needs.

Since the uplink rate of GPON is relatively low, the cost of ONU's sending components (such as lasers) is also low, so the total price of the equipment is low.

2. GPON Features

High bandwidth: GPON can provide transmission rates of up to 2.5 Gbps (uplink) and 1.25 Gbps (downlink), which enables it to meet users' needs for high-speed broadband connections.

Point-to-multipoint architecture: GPON uses a point-to-multipoint optical fiber transmission architecture to connect an optical line terminal (OLT) and multiple optical network units (ONU) through an optical fiber line. This distributed architecture allows multiple users to share the same optical fiber, improving network resource utilization.

Symmetric and asymmetric transmission: GPON supports symmetric and asymmetric transmission, that is, the uplink and downlink transmission rates can be different. This enables the network to better adapt to the needs of different users and applications.

ITU-T standards: The technical specifications of GPON are formulated by the Telecommunications Sector of the International Telecommunications (ITU-T) and are specifically defined in the G.984.x series of recommendations. This provides a unified standard for equipment from different manufacturers and increases the interoperability of equipment.

3. GPON Advantages and Limitations

One of the advantages of GPON is its relatively low cost. Fiber optic networks are often more cost-effective than traditional copper cable networks, especially in large-scale deployments. In addition, GPON supports symmetric and asymmetric transmission, making it suitable for different application scenarios.

However, GPON also has some limitations. Due to its limitations in transmission rate and bandwidth, the network may face bandwidth bottlenecks when user demands continue to increase. Upgrading the GPON system to meet higher requirements may face some technical and economic challenges.

4. GPON Application Scenarios

Home broadband network: GPON provides home users with high-speed and stable broadband connections, supporting high-definition video streaming, online games and other needs.

Enterprise network: In an enterprise environment, GPON can provide reliable communication infrastructure to meet the needs of enterprises for daily office work and large-scale data transmission.

Government and campus networks: GPON is also widely used in government agencies and school networks, meeting the needs of these institutions for high-bandwidth and high-stability networks.

The Key to Optical Network: Optical Switch Technology and Application

With the application of DWDM systems and the development of optical communication technology, optical networking has become the trend of network development. The realization of optical network technology depends on optical devices such as optical switches, erbium-doped fiber amplifiers (EDFA) and wavelength division multiplexer (WDM), and the improvement of optical technology. DWDM (Dense Wavelength Division Multiplexing) technology is the key factor promoting all optical network development, while optical network put great opportunity and challenge in front of equipment manufacturers and telecom operators.

Optical switch is the key in all-optical switching that can achieve routing switching, wavelength selection, OXC and self-healing protection in the all-optical layer. At present, optical switch main applications are:

OXC (optical cross connect). Composed of optical switches arrays, OXC can realize dynamic optical path management, optical network fault protection and flexible new business addition. OXC requires low insertion loss, low crosstalk, short switching time and non-blocking operation. Currently, MEMS technology is put into use.

Realizing network automatic protection switching by optical switch. When fiber breaks or transmission fails, optical switch, like 1x2 optical switch, can change the transmission path to achieve business protection.

Network monitoring by 1xN optical switch. At the optical fiber test points of distal end, 1xN optical switch connects several fibers with OTDR (optical time-domain reflectometer) so as to achieve monitoring of all fibers. Or use the network analyzer to achieve network on-line analysis.

Optical fiber communication device testing. When testing optical device, fiber cable and system product, optical switch is able to test several devices so that thus simplifies the test and increases the efficiency.

OADM. It is mainly used in circular MAN, to achieve a single wavelength and a plurality of wavelengths transmitted in the optical path up and down freely. Optical switch OADM can control any dynamic wavelength up and down by software to boost the flexibility of network configuration.

Conventional optical switching technology mainly uses two technologies: solid state waveguide and optomechanical. Because of high crosstalk and power loss, solid state waveguide is limited in a switches array, not suitable to expansion in a large-scale switch array. While optomechanical has low insert loss and crosstalk, it is also not suitable to large-scale switch array for its large equipment and ordinary expansibility. So far, a lot of new technologies have emerged, mainly including MEMS, Inkjet bubble optical switch, the liquid crystal optical switch, thermo-optic effect switch, acousto-optic switches, holographic switches and so on.

The following specifications are used to examine an optical switch: switching time, array size, insert loss, reliability, expansibility and so forth. The developments of different technologies vary with the different applications. The following is a summary on the major optical switches types and their applications.

MEMS (micro-electromechanical system) optical switches. MEMS is likely to be one of the mainstreams of the core optical switch devices, because it is less affected by the format, wavelength, protocols, modulation, polarization and optical signal transmission direction, but performs better than other types in loss and scalability, which is consistent with the trend of the future development of optical network. The principle is to switch the light route by static electricity or other controls driving the movable micro mirror rotate. In spite of complicated production process, MEMS used IC technology to achieve mass-produces and decrease the individual cost.

Magneto-optic switches. As technology developing fast and expanding its horizon to wider fields, magneto-optic switches emerge as the times require. Magneto-optic switches boast higher switching speed, better durability, higher reliability, low voltage drive, and fail-safe latching. The sophisticated micro-technique is a push to high-technology industry. The applications are promising in high-end science, such as aerospace, military, fire monitoring, oil field detection, medical science and so on. Thus, a manufacture’s strength is reflected in whether it masters the magneto-optic switch technology and is able to produce it.

PON. Optical switches are widely used in PON monitoring system to build up all optical networks nowadays. PON is necessary to fulfill FTTx. With zero natural environment influence like thunder and lightning, PON is the best choice to meet the need of present networking. PON is composed of OLT, ONU, ONT and ODN, while optical switches integrated in these devices play great role to transmit mass data and monitor the networking in case of fault and ensure signal transmission.

Multi-channel optical switches. Optical switches can be integrated into a module or an equipment as multi-channel optical switches featured wide wavelength range, low crosstalk, high stability, high reliability and modularized design. At present, there are 1x4, 1x8, 1x16, 4x4, 1xN, MxN and module-type multi-channel optical switches.

Micro optical switches. It is the fundamental and widely used optical component, including 1x1, 1x2, 2x2, 2x2, D1x2,D1x2B, D2x2, 2x2F and so on. Micro optical switch is famous for its high performance, low insertion loss and compact dimension. It is an ideal component for OADM, OXC, system monitoring and protection. With compact package, it can be easily integrated into a high density optical communication system.

With the popularization of optical networking concept, optical switch technology has become the key to the future all optical network. This article briefly introduces the optical switch technology and application to help understand what is in the optical networking.

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Bandwidth Upgrade Stimulate Next Generation PON Technology Evolution

Bandwidth Upgrade Stimulate Next Generation PON Technology Evolution

    Recently, along with the growing needs of life, a variety of network-based applications are emerging. 3D TV, high-definition TV, 4K TV and even 8K television, virtual reality, and high-quality video services bring unparalleled audio-visual experience, and are becoming more common. Additionally, mobile devices like smartphones and tablet computers enable a large increase in network access devices and connections. In order to cope with such strong demand, PON technology providing high-bandwidth is widely used.

10G PON: the Mainstream Applied Technology of FTTx

      1G PON technology including EPON and GPON provides about 20-50 Mbps bandwidth for the end users. However, such bandwidth cannot fully meet the large bandwidth demand of 4K TV. Thus, ITU-T put forward XG-PON1 technology which can provide 10 Gbps (four times as GPON’s) downstream bandwidth and 2.5 Gbps (two times as GPON’s) upstream bandwidth. IEEE also proposed 10G EPON standard lifting the downstream speed up to 10Gbps. It is significant to have the equivalent bandwidth in some application fields. Nowadays, the research for 10G PON technology has been completed, a series of industry standard has been set, and the specification has been released, like the 802.3av of 10 G EPON, and ITU-T G.987 and G.988 of 10G GPON. In support of these standards, 10G PON devices can be mass-produced.

     Thanks to the mature industry chain and excellent performance, 10G PON has become the mainstream technology. It is suitable for a variety of deployment scenarios, such as buildings, residential renovation, high-end home, small and medium company broadband access, and mobile backhaul. The very key is that 10G PON and 1G PON can perfectly co-exist by reusing ODN and appropriate deployment of wavelength, which means that carriers can more easily achieve the smooth evolution of network construction. For traditional carriers, it helps improve user experience, enhance user stickiness, and maintain competitive position; for new carriers, it offers an idea to boost competitiveness in differentiation and competition.

10G PON Application: Building and Residential Renovation

      This application makes full use of the bandwidth of 10G PON technology, and provides large user covering and access bandwidth up to 100M even to 1G. Moreover, by fully using the existing resources UTP cable, twisted pair, network, etc., it can achieve rapid deployment and service fulfillment, thereby reducing capital expenditures. 

10G PON Application: High-end Home, Enterprise and Campus Broadband Access

      10G PON is the best selection for the brand new allocation serving the high-end users. It provides 1G to 10G bandwidth access sufficient to support high-end home and business users that demand high-bandwidth applications such as high-speed internet access, cloud storage, ultra-high-definition video, and 3D / VR online gaming service. In such situation, 10G PON access helps to improve user satisfaction thus consolidate, and even increase revenue.

10G PON Application: Mobile Backhaul

        In the era of mobile Internet, mobile communication occupies an important share of the communications market. Therefore, it is very necessary to offer carriers with a flexible-access and low-cost mobile traffic bearer solutions that can support massive business. And the 10G PON that can be deployed in various indoor and outdoor scenes is exactly in line with this demand. Not only 10G PON and small cell are perfect match, but also the existing FTTX resources give great convenience to LTE small cell that requires high-density deployments.

NG-PON2: 10G PON in The Future

       The existing mainstream 10G PON can ensure most communication services, yet the demand for bandwidth will be increasing. Ultra high-definition video services including VR and 8K TV, and the new generation mobile communication technology including Pre5G and 5G requires a lot of communication bandwidth, and is likely to bring greater data traffic in the future. Early in 2009, FSAN began researching NG-PON2, the next generation PON networking technology. In 2012, FSAN chose TWDM-PON as the mainstream NG-PON2 technology while PtP WDM PON as supplement. And it is regarded as the milestone in the history of NG-PON2 technology development. By the end of 2015, FSAN has finalized G.989.1、G.989.1 Amd1, G.989.1 Amd2, and a number of technical recommendations. At the same time, IEEE is in full swing researching and developing NG-EPON technology as a next-generation evolution direction for 10G EPON technology.

      At present, NG-PON2 corresponding standard G.989 series is in the research stage. And numerous details involving technical indicators and management methods await further discussion and confirmation. What’s more, the immature chain also greatly limits the commercialization of NG-PON2. Manufacturer’s NG-PON2 product is still in the prototype stage. Some of the key components like standard package optical modules are still very lacking, resulting in much higher cost of NG-PON2 than XG-PON1. Therefore, it is expected that NG-PON2 will be put into scale applications possibly after 2020.