1. Operating Principle and Standards
The main differences between EPON and GPON OLTs lie in the standards they adhere to and the data processing methods they use. Which is better: EPON or GPON OLT?
EPON OLTs use the IEEE 802.3ah Ethernet standard. Like a typical LAN network, they transmit and receive data using simple Ethernet frames. This is the same language used by home computers and Wi-Fi routers. EPON OLTs essentially extend this familiar home network language to the home via fiber optic cables. This makes integration with existing IP-based systems extremely easy.
GPON OLTs, on the other hand, use the ITU-T G.984 standard. They use a special method called GEM (GPON Encapsulation Method) to transmit not only Internet data but also voice and video. This makes GPON OLTs suitable for multi-service networks that require advanced traffic management. Which is better: EPON or GPON OLT?
2. Speed and Bandwidth Support
The OLT determines the amount of data that can be sent and received between users.
A typical EPON OLT port supports 1.25Gbps in both the upstream and downstream directions, which is sufficient for basic internet use like browsing and streaming. Each home's devices are notified by the OLT when they can send data (upstream). This is often achieved through relatively simple scheduling.
GPON OLT ports offer 2.5Gbps downstream and 1.25Gbps upstream speeds, delivering superior performance for high-bandwidth services like HD video, cloud apps, and IP voice. This is due to the GPON OLT's built-in smarter, dynamic traffic control system known as Dynamic Bandwidth Allocation (DBA). The GPON OLT constantly checks how much data each home is actually attempting to transmit. It then adjusts the "time slot" each home receives in real time and with great precision. This often results in more efficient utilization of the entire fiber optic pipe.
Differences in Speed and Bandwidth Support Between EPON and GPON OLTs
3. Splitting Ratio and User Capacity
Both types can typically provide service to homes approximately 20 km (12 miles) away from the OLT. OLT ports are shared among multiple users using optical splitters. The number of users that can connect to a single OLT port is called the splitting ratio.
EPON OLTs typically support up to 64 users per port.
GPON OLTs support up to 128 users per port.
This means that GPON OLTs can handle more users per port, making them useful for large-scale Fiber to the Home (FTTH) deployments. However, if the network is not properly designed, performance may degrade as the number of users per port increases.
4. Network and Device Management:
EPON OLTs use standard Ethernet tools for connection health monitoring and basic management. While simple, they may not provide detailed control over all functions of in-home devices, especially for complex services.
GPON OLTs use a powerful, proprietary management system called OMCI. OMCI is like a remote control system designed specifically for in-home devices (ONTs). The OLT can configure the devices in detail, troubleshoot problems remotely, and precisely configure various services (Internet, telephone, and TV). This is a major benefit if your provider offers bundled services.
5. Device Compatibility
EPON OLTs only work with EPON ONUs, and GPON OLTs only with GPON ONUs. These devices cannot be mixed. Furthermore, if the OLT does not support the same standard as the ONUs, they will not communicate properly.
When upgrading or expanding your network, make sure all devices are of the same system (EPON or GPON). Some OLTs support dual-mode (XPON) and can recognize both EPON and GPON ONUs, providing greater flexibility.
6. Cost and Complexity
EPON OLTs are typically cheaper and easier to deploy and manage. They have lower equipment costs and are easier to configure, making them ideal for small and medium-sized ISPs and enterprise networks.
GPON OLTs are more expensive. The increased complexity of GEM and OMCI once made them more expensive, but their widespread adoption around the world has significantly reduced their prices. They have become the dominant standard in North America, Europe, and many other regions. The cost difference between them is now small.