Next-generation cable TV network EPON EoC solution

The traditional wired network only supports the one-way downlink broadcast service. In order to improve the ARPU value of the user, the operator needs to modify the hybrid fiber coaxial network (HFC) to provide two-way and interactive services. In the Next Generation Broadcast Network (NGB), the EPON + EoC-based next-generation broadcast network architecture provides a simple end-to-end Ethernet-based packet network that works with existing cable TV networks.

This article refers to the address: http://

The traditional wired network only supports the one-way downlink broadcast service. In order to improve the ARPU value of the user, the operator needs to modify the hybrid fiber coaxial network (HFC) to provide two-way and interactive services. In the Next Generation Broadcast Network (NGB), the EPON + EoC-based next-generation broadcast network architecture provides a simple end-to-end Ethernet-based packet network that can operate with existing cable TV networks, as shown in Figure 1. Show.

Figure 1: Next-generation broadcast network architecture

In Figure 1, EoC's central office equipment includes a coaxial cable broadband access terminal (CBAT) and a cable TV signal mixer that provides bridging and management functions for EoC networks to enable two-way services for broadcast television, such as IPTV. VOD, HSD, VoIP and P2P games. This paper introduces the overall background of EPON and EoC technologies, and discusses in depth the EPON EoC solution that can be used for two-way transformation of cable TV networks.

EPON, EoC technology features

EPON: EPON technology provides bidirectional 1Gbs link connectivity with a downstream wavelength of 1490nm and an upstream wavelength of 1310nm. The downlink data stream is transmitted to all ONUs (optical network units), and the LLID field is added to the preamble (logical link ID) to distinguish the destination of the specific frame in the PON network; in the uplink data, the DBA is responsible for the registered ONU. Dynamically allocate bandwidth. The advantages of the EPON system are as follows:

◎ Easy to integrate and simple and practical – EPON is based on Ethernet technology, which can mix and transmit VoIP, IPTV, data and various RF data streams on the same architecture, and provide QoS mechanism to ensure the transmission quality of different data streams.

◎ Long distance – When the EPON network uses Forward Error Correction (FEC), it can be extended to 20 km or even 30 km. The loss of the fiber optic architecture is only 1 dB per 2000 feet.

◎ Low cost – Due to the passive splitter, the operation and maintenance cost will be lower than that of the coaxial cable in the long run.

◎ High reliability – a network that is passive and does not include any power-consuming electronic components, with higher reliability.

EoC: Ethernet Coax (EoC) refers to the transmission of Ethernet signals over two or more points using coaxial cable. Mainly include: baseband (passive system) or radio frequency modulation (active system) two transmission methods. The baseband system is easy to set up and use. The disadvantage is that a point-to-point connection is required to obtain a data rate (>10 Mbps) suitable for the current application requirements of the IP network; the active system can support multiple client devices connected to the same coaxial cable, and all clients It can be controlled by a central office component located at the node. Currently active systems can be divided into two types: systems based on the Multimedia over Coax Alliance (MoCA) industry standard and systems based on the Home Telephone Line Network Alliance (HPNA) standard. The main difference between MoCA and HPNA is the different frequency range used: MoCA is used in the frequency range above 862MHz for local in-building distribution, while in the latest 3.1 version, HPNA uses the 4 to 52MHz frequency range.

EPON + EoC solution

In the domestic cable TV next-generation broadcast network, the EoC central office host device plays a key role - bridging fiber and 2 coaxial cable, and managing the authorization and transmission of client devices in the EoC network. The EoC master device can be classified into two types depending on whether or not the ONU is integrated. as shown in picture 2:

Figure 2: EoC central office main equipment type

In Type A, similar to the ONU currently deployed by the telecommunications company, its ONU is independent of the EoC's central office. The EoC master device consists of a silicon crystal chip (HPNA Master, MoCA network controller device or HomePlug) that controls the CPU, EoC central office technology, and a mixer that superimposes the cable TV signal on the output coaxial cable. With this model, PMC's MSP7150 is an ideal solution for controlling the CPU and PCI bus master controls. In addition, in certain regions, EoC master devices need to provide some functions of Layer 3 gateways, such as routing, NAT, and firewalls, and the hardware and software platforms of the MSP7150 can fully support these functions.

In Type B, the ONU is integrated into the EoC master. This solution greatly reduces the equipment and maintenance cost of cable operators. When using this technology, if the gateway function is not needed, the CPU embedded in the PMC PAS6301 can be used to control the CPU of the EoC network; otherwise, the system needs to add the MSP7150 as the control CPU and provide the corresponding gateway function.

With proven EPON technology, high throughput and flexible software architecture, PMC's EPON EoC solution accelerates the transition of cable TV networks. Figure 3 shows a typical Type B device that uses PMC's ONU, CPU solution, and third-party partner EoC central office host products.

Figure 3: EPON EoC Reference Design

The design of Figure 3 can support more than 400Mbps throughput, multiple EoC master nodes and required network data processing functions, including VLAN, QinQ, PPPoE, DHCP, QoS, WebGUI and SNMP. In addition, it can also support Enhanced service features including routing, firewall, NAT, Wi-Fi and VoIP, and ample expansion to accommodate future applications.

Detailed EoC technology

The following briefly introduces the HPA and MoCA EoC technologies based on the PMC scheme, which are currently used in the system. Other EoC solutions, such as HomePlug, are also more common.

HPNA: HomePNA technology provides QoS bandwidth guarantee, remote management and diagnostic capabilities, and a physical data transfer rate of up to 320Mbps. Its system central office components are not only used as coaxial cable networks and connection gateways based on IP and Ethernet PON networks. And manage all client devices. In HPNA version 3.1 based systems, the main unit can support and control up to 32 client devices connected to a coaxial cable via any tree or star architecture. A typical HPNA architecture is shown in Figure 4.

Four operating modes are defined in the HPNA 3.1 version. These four modes occupy different spectrums, and different networks can choose to use their optimal operating mode.

Table 1: HPNA3.1 version operating mode

Depending on the frequency allocation, the physical data rate can be up to 320Mbps, which enables dynamic allocation among up to 32 client devices in half-duplex mode. (For example, in half-duplex mode, the HPNA system uses the same spectrum range to transmit and receive to client devices).

The HPNA MAC layer protocol is responsible for managing client devices while ensuring maximum bandwidth per client device. In addition to managing client device management, the HPNA MAC layer supports all the functions required to manage QoS bandwidth guarantees and optimizations so that HPNA can be applied to VoIP or similar multimedia applications that require guaranteed transmission bandwidth.

MoCA: MoCA version 1.1 enables MoCA to achieve 175 Mbps MAC layer data throughput at a physical data rate of 270 Mbps. The performance improvement is achieved by integrating multiple Ethernet packets into a single MoCA frame. The latest MoCA 2.0 will be utilized. The idle frequency band above the cable TV service further increases the data transmission rate, making it the EoC technology with the highest data transmission rate. The MoCA network architecture is shown in Figure 5.

Figure 5: MoCA Network Architecture

In the MoCA network, the central office network controller node is responsible for the authentication of the MoCA client device, and controls the transmission of the data in the terminal and the management key through the MAP information. MoCA 1.1 introduces parameterized QoS to support bandwidth reservation and device access control.

In view of the current situation of domestic cable network segmentation, the author believes that in the future of network access technology, the two EoC technologies will not have the ultimate winner. Not only that, but various other technologies that enable Ethernet frames to be transmitted over the home network, such as HomePlug AV and coaxial cable-based WiFi, will also be adopted.

For cable operators, no matter which access technology is chosen in the future, the EPON EoC solution based on PMC's PON chip and CPU can meet their needs.

At present, the domestic Chinese cable TV network is upgrading from the traditional HFC broadcast network to the two-way, interactive, high-speed, all-IP based next-generation broadcast network. As a mature technology, EPON is very suitable to replace the fiber part in the HFC network. After years of development, EoC technology can be deployed as the last 1 km network connection solution. PMC's reference design helps potential system providers develop EPON EoC solutions in a timely manner.

* PMC-Sierra is the industry's leading provider of network architecture semiconductor solutions that support both EPON (IEEE 802.3ah) and GPON (ITU-T G.984) standards and is the first to introduce the industry's first symmetric and asymmetric 10G EPON reference design platform. The PMC-Sierra system-on-a-chip solution is currently running on more than 8 million PON ONU devices worldwide.