ITU-T G.984 is the series of standards for implementing a gigabit-capable passive optical network ( GPON ). It is commonly used to implement the link to the customer (the last kilometre , or last mile ) of fibre-to-the-premises ( FTTP ) services.
7-550: GPON puts requirements on the optical medium and the hardware used to access it, and defines the manner in which Ethernet frames are converted to an optical signal, as well as the parameters of that signal. The bandwidth of the single connection between the OLT ( optical line termination ) and the ONTs ( optical network terminals ) is 2.4 Gbit/s down, 1.2 Gbit/s up, or rarely symmetric 2.4 Gbit/s, shared between up to 128 ONTs using
14-430: A time-division multiple access (TDMA) protocol, which the standard defines. GPON specifies protocols for error correction ( Reed–Solomon ) and encryption ( AES ), and defines a protocol for line control ( OMCI ) which includes authentication (LOID, serial number and/or password). The exact kind of fibre cable and connectors to use is undefined. The primary optical transmitter, known as the optical line terminal (OLT),
21-409: Is housed within the central office of the telecommunications operator. A laser in the OLT injects photons from the central office into a glass-and-plastic fiber-optic cable that terminates at a passive optical splitter. The splitter divides the single signal from the central office into many signals that can be sent to up to 64 consumers. The number of consumers serviced by a single laser is determined by
28-650: The BPON management model. However, G.984.4 removed all references to ATM. G.988 is a stand-alone OMCI recommendation and supersedes G.984.4 except for GPON specifics that are not defined in G.988. Future work on the PON management model is expected to appear only in the GPON space. Security issues in the G.984 standard series include the possibility of eavesdropping on upstream traffic, replay attacks , PLOAM messages that are not integrity protected and denial of service to other subscribers on
35-519: The distance between the central office and the household rises, with severe signal loss beyond 3km, all customers may enjoy high-speed network access within the 16km range of a fibre central office. The first version of GPON was ratified in 2003. Since then, it has been expanded upon and revised several times. Work on the standard continues. As of July 2018, G.984.5 is currently being revised. The most recent version comprises seven parts: The GPON OMCI recommendation G.984.4 draws on G.983 .2, which defines
42-464: The operator's engineering criteria; operators may opt to reduce the number to 32 consumers. Furthermore, the operator may choose to divide the signal twice, for example, once into eight and again farther down the line. The maximum distance between the central office and the site can be 20 kilometers, however operators will normally limit it to 16 kilometers in order to maintain a high level of service. In contrast to ADSL technology, which deteriorates as
49-423: The same link. Optical line termination An optical line termination ( OLT ), also called an optical line terminal , is a device which serves as the service provider endpoint of a passive optical network . It provides two main functions: An OLT can have several ports, and each port can drive a single PON network with split ratios or splitting factors of around 1:32 or 1:64, meaning that for each port on
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