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.
千人斩官网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
千人斩官网 Saturation Optical Power: -8dBm
What is your ONT Tx power level and RX sensitivity?
The OLT support Class B+.
PON port speed: symmetrical 1.25Gbps
Waves: 1310nm TX,1490nm RX
TX Optical power : 0～5dBm
千人斩官网 RX Sensitivity: -27dBm
How many ONU can 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 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.
C-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 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？
千人斩官网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.
EPON and GPON which is better？
千人斩官网EPON compatible with the current Ethernet technology for the purpose of the 802.3 protocol in the optical access network continuation of the full inheritance of the Ethernet low prices, flexible protocol, mature technology and other advantages, with a wide range of markets and good compatibility.
千人斩官网The GPON is positioned in the telecommunications industry for multi-service, full-service access with QoS guarantees, and strive to find the best and most business-friendly solution with the highest efficiency. It proposes that “all agreements be openly and completely thoroughly Reconsider “.
Overall, EPON and GPON have their own strengths and weaknesses, from the performance indicators GPON is better than EPON, but EPON has the advantage of time and cost, GPON is catching up, looking forward to the future of broadband access market who may not be replaced, it should be Co-existence and complementarity. GPON will be more suitable for customers with high bandwidth, multi-service, QoS and security requirements and ATM technology as the backbone. For cost-sensitive, QoS, security, less demanding customer base, EPON has become the dominant.
What is 10G PON?
千人斩官网Broadband access Gigabit access era, 10G PON PON has become the mainstream technology, the traditional PON is to 10G PON upgrade, broadband will increase 10 times. 10G PON scale commercial launch, will directly help FTTH to Gigabit access rate evolution. The company is located in:
千人斩官网10G PON has many advantages, based on the existing hardware architecture to upgrade the network, greatly reducing costs, and shorten the transformation cycle, more crucially, PON upgrade to 10G PON, the bandwidth can be increased 10 times. Only through the upgrading of key components, you can enter the “Gigabit era” from the “Fast trillion times.”
千人斩官网Gigabit bandwidth is not the limit, with the rapid development of 8K ultra-high definition video and Internet of Things technology, especially the advent of the 5G era, will bring greater bandwidth demand for the network growth, in this context, 10G PON will continue Development, will be 100G PON evolution.
From the standard progress, 100G PON has been in IEEE / FSAN / ITU-T and other standardization organizations. IEEE set up the NG EPON research group, the standard named P802.3ca, mainly for 25G PON, 50G PON, 100G PON standardization is scheduled to be released in May 2019 standards; ITU-T also set up a 25G PON research group, Research on single wavelength rate improvement.
What is pon?
A passive optical network (PON) is a system that brings optical fiber cabling and signals all or most of the way to the end user. Depending on where the PON terminates, the system can be described as fiber-to-the-curb (FTTC), fiber-to-the-building (FTTB), or fiber-to-the-home (FTTH).
Downstream signal coming from the central office is broadcast to each customer premises sharing a fiber. Encryption is used to prevent eavesdropping. Upstream signals are combined using a multiple-access protocol, usually time division multiple access (TDMA).
A PON consists of an optical line terminal (OLT) at the service provider’s central office (hub) and a number of optical network units (ONUs) orOptical Network Terminals (ONTs), near end users.
What is FTTH?
千人斩官网Since its promotion in 2003, FTTH has gone through 14 years. Since its launch in 2013, “Broadband China” has experienced another four years. FTTH has evolved from the dream of optical communications people to reality and has become a place where people work, study and live Indispensable infrastructure.
千人斩官网FTTH is an abbreviation for fiber optic directly to the home, abbreviated as FTTH in Chinese. Specifically, FTTH refers to installing an ONU at a home user or an enterprise user, and is an optical access network application type closest to a user except an FTTD (fiber to the desktop) in the optical access family. The significant technical feature of FTTH is that it not only provides more bandwidth, but also enhances the transparency of the network to data formats, rates, wavelengths and protocols, relaxes the requirements for environmental conditions and power supply, and simplifies maintenance and installation. When it comes to FTTH, you first have to talk about fiber access. Optical fiber access refers to the central office and users entirely between the optical fiber as a transmission medium. Optical access can be divided into active optical access and passive optical access. The main technology of optical subscriber network is optical transmission technology. At present, the multiplexing technology of optical fiber transmission develops quite fast, and most of them are in practical use. According to the depth of fiber users, can be divided into FTTC, FTTZ, FTTO, FTTF, FTTH and so on.
What is FTTB?
千人斩官网FTTB (Fiber To The Building): FTTX + LAN is a network connection mode, the optical signal is mainly connected to the office building or apartment building within the main distribution box to achieve optical fiber signal access, and in the office building or The interior of the apartment building is still the use of coaxial cable, twisted pair or fiber optic distribution signal to achieve the realization of high-speed data applications. We call FTTX + LAN broadband access network (referred to as FTTB), this is one of the most reasonable, most practical, most cost-effective broadband access methods.
Fast: Fiber to the floor, cable home, the user uplink and downlink rates generally up to 10Mbps-50Mbps, up to 100Mbps.
Large capacity: each household can enjoy the two-way balanced 10M-50Mbps bandwidth.
千人斩官网Investment Province: FTTB is mainly used for transformation of old residential areas. Residential areas that already have network cables, telephone lines and coaxial cables do not need to deploy optical fibers and save a large amount of wiring expenses.
Low price: Unit bandwidth is cheaper than FTTH and CMTS
千人斩官网Wide range of applications: High-speed Internet access, VOD, SOHO, distance education, video conferencing, ROBO, telemedicine and Internet connectivity.
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.
千人斩官网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.
The difference between HGU, SFU, MDU, MTU and SUB
SFU (Single Family Unit) single-family unit ONU
千人斩官网It is mainly used for single home users in FTTH scenarios and ordinary terminals that only support broadband access. Generally, it has 1 to 4 Ethernet interfaces and provides Ethernet / IP services. The built-in optical equipment or IAD equipment can support CATV services or VoIP business. Now often used in conjunction with home routers to provide greater business capabilities.
HGU (Home Gateway Unit) Home gateway unit type ONU
千人斩官网It is mainly used for single home users in FTTH occasions. Compared with SFU, which has the function of home gateway, it is equivalent to a home gateway with PON uplink interface. It generally has 2 ~ 4 Ethernet interfaces, 1 WLAN interface and 1 USB interface. Provide Ethernet / IP services, through the built-in optical or IAD devices can support CATV business or VoIP services, support TR-069 remote management.
MDU (Multi.Dwelling Unit) multi-family unit ONU
Mainly used in FTTB / FTTC / FTTCab mode for multiple residential users occasions, with broadband access terminal functions, usually with at least 4 user-side interfaces in the telecom operators equipment selection, often including Ethernet interfaces, ADSL2 + Interface or VDSL2 interface to provide Ethernet / IP services. In the radio and television operators of the network applications, due to differences in business content, generally only contains the Ethernet interface for PON + LAN access.
MTU (Multi-tenant Unit) Multi-tenant unit type ONU
千人斩官网It is mainly used for multiple enterprise users in the FTTB scenario or multiple individual users in the same enterprise. It has the function of broadband access terminal and has multiple Ethernet interfaces (usually at least eight), E1 interfaces and POTS interfaces, and provides Ethernet Network / IP services, TDM services and VoIP services (built-in IAD).
SBU (Single Business Unit) single-business unit ONU
Mainly used in the case of FTTO, separate business users and businesses in a single office access. Support broadband access terminal functions, in the telecom operation network, generally with Ethernet interface, E1 interface, VOIP interface, etc., to provide Ethernet / IP services and TDM services.