GPON and XGS-PON Networks: Coexistence of Technologies and Use of Infrastructure

Tatiane Figueiredo – Training Instructor

It is indisputable and already widely recognized that we live in an era where the demand for video on demand services is continually growing, driven by the prevalence of mobile devices, such as smartphones, tablets and laptops, accessing the network simultaneously. Adding to this reality, we have the Internet of Things (IoT), which, although not new, continues to revolutionize our homes with constant innovations. The scenario of online classes and remote work, already well established, demonstrate the transformative power of technology in reducing barriers and bringing people together. In this scenario, it is not surprising that fiber optic networks have experienced robust growth in Brazil and around the world, solidifying themselves as the main technology in 2022, as highlighted by a survey by the Teleco website:

The expectation for the coming years, in addition to seeing fiber optics expanding to increasingly remote regions, is the growth and intensification of competition for speed. In a few years, Brazil is expected to reach an average fixed broadband speed of 1Gbps in the residential environment.

This demand poses a significant challenge for Internet providers and operators, not only to meet their customers' expectations, but also to live up to the financial investment spent on building the physical infrastructure, purchasing equipment and training their technical teams.

Considering the evolution of the GPON optical network, in order to preserve part of the investment made and offer plans with broader capabilities for its customers, aligned with the accelerated pace of content consumption, becomes a viable strategy. In this context of an imminent future, XGS-PON technology emerges, offering support for sharing bandwidth on the same physical medium at rates of 10Gbit/s, coexisting harmoniously with GPON technology, already consolidated in countless homes and companies. Furthermore, adopting this approach makes it easier for customers to transition between technologies, minimizing disruptions and restricting only the time required for provisioning.

The coexistence between the technologies occurs due to the fact that they operate in downstream wavelengths, from the OLT to the ONU, and upstream, from the ONU to the OLT, in different windows, as can be seen below.

Regarding the main characteristics, it is observed:

In addition to the need for special care with the power budget of the PON network, a passive device has gained relevance both for coexistence and in the transition between technologies called WDMr1. Which is responsible for combining two or more different wavelengths in the same fiber, behaving like a multiplexer/demultiplexer.

There are versions of one – WDMr1 and four ports – WDMr4:

Its physical appearance and logical design resemble a Splitter, however, its action is not aimed at dividing but rather at combining. When adding it to the passive optical distribution network, as seen in the image below, a loss of approximately 1dB will be added to the power budget, in both technologies.

With their insertion in the topology, the GPON and XGS-PON technologies, each with their respective wavelength, will be multiplexed and propagated through the same fiber by WDMr1, reaching the desired ONU, which will be provisioned and will act on the speed according to its characteristic, whether GPON or XGS-PON.

The ONU, in turn, will send the signal according to its characteristics, which, when arriving at WDMr1, will demultiplex it, delivering it to the correct port.

The definition of how the provisioning of the device installed on the client will occur will depend on the technology present in the ONU, whether GPON or XGS-PON, as well as the OLT.

Various topologies can be built aiming at the coexistence of technologies, allowing the Internet provider or telecommunications operator to achieve greater optimization of their resources and consequently improve the quality of the services offered, some of them are:

1- GPON and XGS-PON in different OLT

2- GPON and XGS-PON on the same OLT, via hybrid or exclusive port

At the residential level, plans with higher speeds require upgrades in CPE devices, often to newer technologies, such as the use of AX or WiFi 6 model wireless routers.

The equipment present inside homes, those used by the end user, must also be analyzed by the service provider, so that the user experience is complete.

XGS-PON is especially attractive for serving corporate customers, allowing the offering of dedicated plans. It can also be used for direct benefit, providing the delivery of links to other OLTs, as illustrated below.

In an environment where the demand for higher speeds and broad coverage grows by leaps and bounds, Datacom emerges as a reference offering a comprehensive portfolio of GPON and XGS-PON solutions. In highlight, we present our OLT XGS-PON DM4616: compact, it represents an efficient option for those looking for migration and expansion without the need for large investments in large equipment. In addition, our portfolio extends to passive devices, such as WDMr1 and WDMr4, and the ONU in SFP format, designed especially for corporate scenarios.

As throughput in access networks increases, it is vital to consider the direct impact this will have on backbone capacity. Datacom, aware of this interrelationship, provides robust equipment for Ethernet transport at layer 2, layer 3 and MPLS. This way, we guarantee not only expansion, but the sustainability and resilience of your network.

Our technical and commercial team is available to accompany you on this journey, ensuring excellence and progress for your business.