Shenzhen C-Data Technology Co., Ltd.
Shenzhen C-Data Technology Co., Ltd.
More (CMS)
  • What is the purpose of the LLID in EPON?

    If the OLT (the central node of the EPON) were to be implemented as a PHY with a single MAC attached to it, this would cause serious trouble for any bridge (=switch) to which the MAC were connected. Consider a MAC frame coming into the bridge from an ONU (a subscriber node) via an EPON port. The bridge associates the source address of the frame with the port on which it came in, i.e. the EPON port. When at a later time another MAC frame comes in from an ONU, this time destined for the MAC address previously learned, it will not be transmitted back to the EPON port, because the bridge assumes that the frame was already received by all the stations on the attached “broadcast” LAN. However, this is not the case; upstream transmissions are not received by other ONUs. Standard bridging has no way of accomodating an attached LAN that behaves as a broadcast LAN in downstream and as a point-to-point LAN in upstream.

    The solution to this problem was designed in close cooperation with Working Group 802.1. Instead of one single MAC, the OLT would have a different dedicated MAC for every ONU attached to the EPON. As a result, higher layers can consider the EPON as a collection of logical point-to-point links. From the individual MACs down to the OLT PHY, the logical point-to-point links share a common GMII; hence, a way to identify data frames for/from the different ONUs is required. The Logical Link identifier (LLID) was created for this purpose. The LLID is carried along by the frame in the bytes of its preamble.

  • How the Data Transfer in an EPON System?

    An EPON system uses the single-fiber wavelength division multiplexing (WDM) technology (with downlink central wavelength of 1490 nm and uplink central wavelength of 1310 nm) to implement single-fiber bidirectional transmission, supporting a transmission distance of up to 20 km (12.43 miles)

  • What's the ONU Optical TX Power and RX Sensitivity?

    Wavelength: Tx 1310nm, Rx1490nm

    Tx Optical Power: 0~5dBm

    Rx Sensitivity: -27dBm

    Saturation Optical Power: -8dBm

  • What is your ONT TX Power Level and RX Sensitivity?

    The OLT support Class B+.

    Transmission Distance:20KM

    PON port speed: symmetrical 1.25Gbps

    Waves: 1310nm TX,1490nm RX

    TX Optical power : 0~5dBm

    RX Sensitivity: -27dBm

  • How many ONU and your OLT Connect?

    The ONU quantity connected to the OLT depend on the OLT PON ports quantity and optical splitter ratio.

    For example, 2PON port OLT can connect 64pcs EPON ONU in 1:32 splitter ratio; If in 1:64 ratio, it can manage 128pcs ONU.

  • What is EPON?

    Ethernet Passive Optical Network (EPON), defined by IEEE 802.3ah, is a point to multipoint (Pt-MPt) network topology implemented with passive optical splitters, along with optical fiber PMDs that support this topology. EPON is based upon a mechanism named MPCP (Multi-Point Control Protocol), which uses messages, state machines, and timers, to control access to a P2MP topology. Each ONU in the P2MP topology contains an instance of the MPCP protocol, which communicates with an instance of MPCP in the OLT. On the basis of the EPON/MPCP protocol lies the P2P Emulation Sublayer, which makes an underlying P2MP network appear as a collection of point-to-point links to the higher protocol layers (at and above the MAC Client). It achieves this by prepending a Logical Link Identification (LLID) to the beginning of each packet, replacing two octets of the preamble. In addition, a mechanism for network Operations, Administration and Maintenance (OAM) is included to facilitate network operation and troubleshooting.

  • What is MC?

    A fiber media converter ( MC for short) is a simple networking device that makes it possible to connect two dissimilar media types such as twisted pair with fiber optic cabling. They were introduced to the industry in the 1990s, and are important in interconnecting fiber optic cabling-based systems with existing copper-based, structured cabling systems. They are also used in metropolitan area network (MAN) access and data transport services to enterprise customers.

  • What is GPON?

    GPON (Gigabit-Capable PON) technology is based on the latest generation of broadband passive optical integrated access standard based on the ITU-TG.984.x standard. It has many advantages such as high bandwidth, high efficiency, large coverage and rich user interface. Most operators regard the access network as a broadband technology, integrated transformation of the ideal technology. GPON was originally proposed by the FSAN in September 2002. On this basis, ITU-T completed the formulation of ITU-T G.984.1 and G.984.2 in March 2003 and completed G in February and June 2004. 984.3 standardization. Which eventually formed a GPON standard family.

  • Is the Wireless AP Meet 802.11AC?

    Yes, C-Data Wireless Ap Ceiling type CW8837AP and outdoor type CW9833AP both meet 802.11ac standard.

  • What is Wireless AP?

    A wireless AP (AP, Access Point, Wireless Access Point, Conversation Point, or Access Bridge) is a well-known name that includes not only simple wireless access points (wireless APs), but also wireless routers Gateway, wireless bridge) and other types of equipment collectively. It mainly provides wireless workstations for wired LAN and wired LAN access to wireless workstations, wireless access point within the coverage of wireless workstations can communicate with each other.

    Simple wireless AP is a wireless switch that provides wireless signal transmission and reception functions. Simple wireless AP’s working principle is the network signal transmitted over twisted pair, after AP product compilation, the electrical signal is converted into a wireless signal sent out to form a wireless network coverage. According to different power, it can achieve different degrees and different ranges of network coverage, the maximum wireless AP coverage of up to 500 meters. Most simple wireless AP itself does not have the routing function, including DNS, DHCP, Firewall, server functions must have independent routing or computer to complete.

  • What is EOC?

    Ethernet Over Coax also called EOC for short. It is an equipment which used for triple play service in a new generation broadcasting network. Widely used by consumers and telecommunications operators in existing 75 ohm coaxial cable installations (from cable television or CATV), to carry broadband data into and through the home, and into multiple dwelling unit (MDU) installations.

    Data EOC network is built with EOC Master and EOC Slave.

  • What is HFC?

    Hybrid fiber-coaxial (HFC) is a telecommunications industry term for a broadband network that combines optical fiber and coaxial cable.

    In a hybrid fiber-coaxial cable system, the television channels are sent from the cable system’s distribution facility, the headend, to local communities through optical fiber trunk lines. At the local community, a box called an optical node translates the signal from a light beam to electrical signal, and sends it over coaxial cable lines for distribution to subscriber residences. The fiberoptic trunk lines provide adequate bandwidth to allow future expansion and new bandwidth-intensive services.

  • What is the function of switch?

    ONU consists of active Optical Network Unit and passive Optical Network Unit.It has two functions: selective reception of the broadcast sent by OLT, and receiving response to OLT if the data is needed;The Ethernet data that the user needs to send is collected and cached, and the cached data is sent to the OLT side according to the assigned send window.

  • What's the difference? Switch VS Router

    Switches, routers are almost all network devices used in modern local area networks. Among them, switches are responsible for connecting network devices (such as switches, routers, firewalls, wireless APs, etc.) and terminal devices (such as computers, servers, cameras, network printers, etc.) ); The router realizes the interconnection between the local area network and the local area network, and the interconnection between the local area network and the Internet; In general, the switch is responsible for connecting devices, the router is responsible for connecting to the network.


    The function of the switch is to connect terminal devices such as computers, servers, network printers, network cameras, IP phones, and realize the interconnection with other network devices such as switches, wireless access points, routers, network firewalls, etc., so as to build a local area network and realize all devices Communication between.

    The switch is located in the second layer (data link layer) of the OSI reference model. The work of the switch relies on the identification of the MAC address (all network devices have a unique MAC address, which is usually directly burned into the network card by the manufacturer) ).


    Routers are also called gateways, which connect local area networks to form a larger wide area network. When connecting heterogeneous networks (heterogeneous networks refer to different network types, such as ATM networks, FDDI networks, Ethernet networks, etc.). Heterogeneous networks use different data encapsulation methods and cannot communicate directly, and routers can “translate” these different encapsulated data to achieve communication in heterogeneous networks. In addition, for the local area network, the wide area network is undoubtedly a heterogeneous network.

    In general, the main differences between routers and switches are reflected in the following aspects:

    (1) Different levels of work

    The original switch worked at the data link layer of the OSI/RM open architecture, which is the second layer, and the router was designed to work at the network layer of the OSI model from the beginning. Since the switch works on the second layer of OSI (data link layer), its working principle is relatively simple, while the router works on the third layer of OSI (network layer), it can get more protocol information, and the router can make Smarter forwarding decisions.

    (2) The data forwarding is based on different objects

    The switch uses the physical address or MAC address to determine the destination address of the forwarded data. The router uses the ID numbers (ie IP addresses) of different networks to determine the address for data forwarding.

    (3) Traditional switches can only divide conflict domains, not broadcast domains; routers can divide broadcast domains

    The network segment connected by the switch still belongs to the same broadcast domain. Broadcast data packets will spread to all network segments connected to the switch, and in some cases will cause communication congestion and security vulnerabilities. Although the switches above the third layer have the VLAN function, they can also be divided into broadcast domains, but the sub-broadcast domains cannot communicate, and the communication between them still requires a router.

    (4) The router provides firewall services

    The router only forwards data packets with specific addresses, and does not transmit data packets that do not support routing protocols and network data packets whose purpose is unknown, which can prevent broadcast storms. Switches are usually used for LAN-WAN connections. Switches are classified as bridges, which are devices at the data link layer. Some switches can also achieve Layer 3 switching. In contrast, routers are more powerful than switches, but they are relatively slow and expensive. The three-layer switch combines the wire-speed packet forwarding capability of the switch and the good control function of the router, so it is widely used.


    Whether it is a switch, a router , the realization of the functions of these network devices requires the network engineer to configure the device in advance (such as VLAN virtual network port division, firewall security policy configuration, router default gateway setting, etc.). At a different level, these network devices are computers with cpu and memory, and all implement hardware functions through the “translation” of the cpu to the machine language.

  • How to choose the right Switch?

    Switches are the common equipment for data forwarding in local area networks(LAN), and their performance and functions determine the manageability and data forwarding performance of the LAN. The following aspects should be considered when choosing a switch:

    Number of ports

    The number of physical ports supported by the switch determines the number of terminals or secondary devices connected to the switch, which need to be selected according to actual needs. Of course, subsequent network expansion needs to be considered. The access port of the switch is used to connect the internal network terminal, and the uplink port is used to connect to the upper-level equipment.

    2.Port Speeds and Types

    Switches come in Fast Ethernet and Gigabit Ethernet. Fast Ethernet allows up to 100 Mb/s of traffic per switch port while Gigabit Ethernet allows up to 1000 Mb/s of traffic per switch port. These ports may be a combination of SFP/SFP+ slots for fiber connectivity, but more commonly they are copper ports with RJ-45 connectors on the front, allowing for distances up to 100 meters. With Fiber SFP modules, you can go distances up to 40 kilometers. Currently, Gigabit Ethernet is the most popular interface speed though Fast Ethernet is still widely used, especially in price-sensitive environments.

    3.Switch access capacity

    The amount of equipment attached to the switch is mainly reflected in the depth of the MAC address table of the switch. At the same time, it is also necessary to pay attention to the number of host routing entries for the three-layer switch. For example, when selecting a Layer 3 switch, the number of all access terminals of the Layer 3 switch is required to be less than the number of host routing entries of the Layer 3 switch.

    4.Network scale and switch network structure

    Considering the scale and level of switch application networks, which are mainly divided into small and medium-sized networks and large and medium-sized networks, the recommendations are as below:

    5.Functional support

    Divide VLANs to realize that ports belonging to different VLANs can’t communicate with each other; Set static routes to realize that VLANs of different network segments can communicate with each other; DHCP snooping prevents the access of other DHCP servers from affecting the LAN. The above functions are commonly used in large and medium LANs.

    6.Safety function

    Specifically, such as: Access Control List, 802.1X authentication(Radius,Tacacs+), loopback detection, IGMP Snooping, etc.

    7.Power requirements

    At any layer, a modern switch may implement power over Ethernet (PoE), which avoids the need for attached devices, such as a VoIP phone or wireless access point, to have a separate power supply. Since switches can have redundant power circuits connected to uninterruptible power supplies, the connected device can continue operating even when regular office power fails. Another characteristic you consider when choosing a switch is PoE. This is the ability of the switch to deliver power to a device over the existing Ethernet cabling. To find the switch that is right for you, all you need to do is choose a switch according to your power needs. When connecting to desktops which do not require PoE switches, the non-PoE switches are a more cost-effective option.

More (CMS)
  • Data lost after installing a new version of CMS?

    1. When uninstalling the old version of CMS, please choose to keep user data.

    2. The installation path needs to be kept on the same path as the previous version.

  • Failed to start the CMS service?

    1. Please check whether the service port is occupied. If so, click the corresponding service tab to modify the port number.

    2. Please export the log information and feed it back to C-DATA Technical support.

  • Master Administrator Forgot Password?

    In the lower right corner of the CMS Panel, click the "Reset Password" button to reset the password.

  • Failed to bind the ONU?

    1. Check whether the ONU Web report parameters are correct.

    2. Currently, the default number of TR069 channels is 100. Please confirm whether the number of bound devices has reached the upper limit. If you need to increase the number, hoping you can contact the C-DATA sales staff.

    3. The system firewall has enabled the option to block all inbound connections in the public network settings, which means that all incoming connection requests to the computer will be denied.

  • The WAN/LAN configuration options do not exist, or the configuration fails?

    The CMS system currently only supports products using the RTL9607C chip to upgrade the new version of the firmware, and other models will be compatible one after another.

  • For the same device, why are there two records with different SNs in the ONU list?

    For the SN of GPON, the value of the old firmware is the serial SN and the new firmware (version number: XXX and above) is changed to the PON SN, which will cause the old device to be recognized as a new device after upgrading, so there are two records, and the serial SN can be Records are permanently deleted.

  • What is CMS?

    CMS stands for Cloud Management System, designed for managing the operational processes of small and medium-sized operators. It includes functions such as device activation, device management, alarm modules, statistical modules, and integrates ACS server (TR069) for centralized ONU management. The addition of an AI module provides intelligent data statistics and analysis during operations. The system also offers a mobile app for real-time network monitoring. With a B/S structure, it supports private deployment, SAAS deployment, and other flexible deployment methods to meet various operational requirements.

  • What is CMS's Positioning?

    CMS is positioned as an operational management software system, addressing various pain points and challenges faced by small and medium-sized operators. It not only manages devices but gradually integrates and manages the entire network equipment, including AI data analysis to assist operators in network management.

  • Key Functions of CMS:

    CMS manages self-branded devices, integrates third-party terminal (ONU) management (TR069), adds third-party head-end equipment (OLT) management, includes an AI module for intelligent data analysis and recommendations, incorporates authentication billing modules to meet the needs of small and medium-sized operators. It also provides a mobile app for user convenience.

  • Advantages of CMS:

    CMS advantages lie in managing third-party ONU and OLT, providing AI data analysis, supporting cloud deployment, offering a user-friendly app, and addressing the rapid response and flexible customization needs of small and medium-sized operators.

  • CMS Architecture and Deployment:

    CMS adopts a B/S architecture, supports cloud services, provides an accompanying app for installation, and offers various deployment methods (public, private, semi-private deployment) for complete network control.

  • Compatibility with Existing Systems:

    CMS supports coexistence mode, allowing existing software to connect via northbound interfaces for unified network management.

    It can also operate in replacement mode, managing third-party devices (ONU, OLT) in a centralized manner.

  • Third-Party ONU Management:

    CMS integrates ACS functionality, enabling unified management of all terminal devices (ONU) through TR069.

  • Benefits for Distributors and Operators:

    For operators, CMS provides unified management, intelligent data analysis, and convenient app-based management. For distributors, a distributor version is available for smaller user scales, offering unified deployment of sold ONUs, simplified account management, and retaining operator-level functionalities.

  • Installation and Usability:

    CMS adopts B/S architecture, allowing one-click installation via a browser. SAAS deployment eliminates the need for installation. Professional UI design and graphical interfaces make it user-friendly.

  • Difference from Traditional EMS:

    CMS is positioned as an operational management software system, while EMS is a previous-generation network management software mainly focused on device management. CMS has a B/S architecture, supports cloud services, and offers extended functionalities such as third-party device management, AI data analysis, and authentication billing modules.

Subscribe Us
Subscribe to be the first to hear about news and upcoming products