EPON（Ethernet Passive Optical Network）
Ethernet passive optical network is a PON technology based on Ethernet. It adopts a point to multipoint structure and passive fiber optic transmission, providing multiple services over Ethernet. EPON technology is standardized by the IEEE802.3 EFM working group. In June 2004, the IEEE802.3EFM working group released the EPON standard - IEEE802.3ah (merged into the IEEE802.3-2005 standard in 2005).
In this standard, Ethernet and PON technologies are combined, with PON technology used at the physical layer and Ethernet protocol used at the data link layer, utilizing the topology of PON to achieve Ethernet access. Therefore, it combines the advantages of PON technology and Ethernet technology: low cost, high bandwidth, strong scalability, compatibility with existing Ethernet, convenient management, etc.
GPON(Gigabit-Capable PON)
The technology is the latest generation of broadband passive optical integrated access standard based on ITU-TG.984. x standard, which has many advantages such as high bandwidth, high efficiency, large coverage area, and rich user interfaces. It is regarded by most operators as the ideal technology for achieving broadband and comprehensive transformation of access network services. GPON was first proposed by the FSAN organization in September 2002. Based on this, ITU-T completed the development of ITU-T G.984.1 and G.984.2 in March 2003, and standardized G.984.3 in February and June 2004. Thus, the standard family of GPON was ultimately formed.
GPON technology originated from the ATMPON technology standard that gradually formed in 1995, and PON stands for "Passive Optical Network" in English. GPON (Gigabit Capable Passive Optical Network) was first proposed by the FSAN organization in September 2002. Based on this, ITU-T completed the development of ITU-T G.984.1 and G.984.2 in March 2003, and standardized G.984.3 in February and June 2004. Thus, the standard family of GPON was ultimately formed. The basic structure of devices based on GPON technology is similar to existing PON, consisting of OLT (Optical Line Terminal) at the central office, ONT/ONU (Optical Network Terminal or Optical Network Unit) at the user end, ODN (Optical Distribution Network) composed of single-mode fiber (SM fiber) and passive splitter, and network management system connecting the first two devices.
The difference between EPON and GPON
GPON utilizes wavelength division multiplexing (WDM) technology to enable simultaneous uploading and downloading. Usually, a 1490nm optical carrier is used for downloading, while a 1310nm optical carrier is selected for uploading. If TV signals need to be transmitted, a 1550nm optical carrier will also be used. Although each ONU can achieve a download speed of 2.488 Gbits/s, GPON also uses Time Division Multiple Access (TDMA) to allocate a certain time slot for each user in the periodic signal.
The maximum download rate of XGPON is up to 10Gbits/s, and the upload rate is also 2.5Gbit/s. It also uses WDM technology, and the wavelengths of the upstream and downstream optical carriers are 1270nm and 1577nm, respectively.
Due to the increased transmission rate, more ONUs can be split according to the same data format, with a maximum coverage distance of up to 20km. Although XGPON has not been widely adopted yet, it provides a good upgrade path for optical communication operators.
EPON is fully compatible with other Ethernet standards, so there is no need for conversion or encapsulation when connected to Ethernet based networks, with a maximum payload of 1518 bytes. EPON does not require the CSMA/CD access method in certain Ethernet versions. In addition, as Ethernet transmission is the main method of local area network transmission, there is no need for network protocol conversion during the upgrade to a metropolitan area network.
There is also a 10 Gbit/s Ethernet version designated as 802.3av. The actual line speed is 10.3125 Gbits/s. The main mode is a 10 Gbits/s uplink and downlink rate, with some using 10 Gbits/s downlink and 1 Gbit/s uplink.
The Gbit/s version uses different optical wavelengths on the fiber, with a downstream wavelength of 1575-1580nm and an upstream wavelength of 1260-1280nm. Therefore, the 10 Gbit/s system and the standard 1Gbit/s system can be wavelength multiplexed on the same fiber.
Triple play integration
The convergence of three networks means that in the process of evolution from telecommunication network, radio and television network, and Internet to broadband communication network, digital television network, and next-generation Internet, the three networks, through technical transformation, tend to have the same technical functions, the same business scope, network interconnection, resource sharing, and can provide users with voice, data, radio and television and other services. Triple merger does not mean the physical integration of the three major networks, but mainly refers to the fusion of high-level business applications.
The integration of the three networks is widely used in various fields such as intelligent transportation, environmental protection, government work, public safety, and safe homes. In the future, mobile phones can watch TV and surf the internet, TV can make phone calls and surf the internet, and computers can also make phone calls and watch TV.
The integration of the three networks can be analyzed conceptually from different perspectives and levels, involving technology integration, business integration, industry integration, terminal integration, and network integration.
Broadband technology
The main body of broadband technology is fiber optic communication technology. One of the purposes of network convergence is to provide unified services through a network. To provide unified services, it is necessary to have a network platform that can support the transmission of various multimedia (streaming media) services such as audio and video.
The characteristics of these businesses are high business demand, large data volume, and high service quality requirements, so they generally require very large bandwidth during transmission. Furthermore, from an economic perspective, the cost should not be too high. In this way, high-capacity and sustainable fiber optic communication technology has become the best choice for transmission media. The development of broadband technology, especially optical communication technology, provides necessary bandwidth, transmission quality, and low cost for transmitting various business information.
As a pillar technology in the contemporary communication field, optical communication technology is developing at a rate of 100 times growth every 10 years. Fiber optic transmission with huge capacity is the ideal transmission platform for the "three networks" and the main physical carrier of the future information highway. Large capacity fiber optic communication technology has been widely applied in telecommunications networks, computer networks, and broadcasting and television networks.
Post time: Dec-12-2024