traffic by using GPON encapsulating method. (GEM). 2. GPON fundamentals. Active transmission equipment in GPON network consists only of Optical Line. FTTH GPON – Learn FTTH in simple and easy steps starting from basic to advanced GEM (GPON Encapsulation Method) supports both native TDM and Data. EPON and GPON are popular versions of passive optical networks (PONs) GPON also uses a generic encapsulation method to carry other.

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DBA is a methodology that allows quick adoption of users’ bandwidth allocation based on current traffic requirements and it is especially good for dealing with bursty upstream traffic.

This is called Ranging. The optical paths can vary between 2 to How to select a right optical fiber? Each upstream frame contains a number of transmission bursts coming from one or more ONUs. In some existing CATV operator network or some telecom upgrading projects eg The physical layer overhead PLOu at the start of the ONU upstream burst contains the preamble which ensures proper physical layer operation of the burst-mode upstream link.

A single fibre from the OLT runs to a passive Optical Splitter passive means, it does not require any power to operate which is located near the users’ locations. It is a recipient of upstream bandwidth allocations within the ONU. However, if a client on campus as students, hostels, schools, colleges, hospitals, or corporate offices, where there is already CAT-5 copper cable is laid, ONU can serve as a more appropriate solution.


Each GEM port bears one kind of service traffic i. It is allocated by OLT i. GFP allows direct encapsulation of variable length packets without repeating the encapsulation overhead on a regular basis. The Ident field contains an 8-KHz Superframe Counter field which is employed by the encryption system, and may also be used to provide low rate synchronous reference signals. The Slot Start and Stop field indicates the beginning and ending of upstream transmission window.

From the Optical Splitter, a single mode SM fibre strand run to each user. A scheduler is used to transmit frames to the U interface. The number of entries is given in the Plend field. The GEM channels carry variable-length Ethernet frames. There are three categories or classes of components, which are based on power and sensitivity. The downstream GTC frame provides the common time reference for the PON and common control signaling for the upstream.

Because the access network is shared, ONU upstream transmissions could collide if they were transmitted at random times. The ODN optical splitters divide the single fiber into multiple fibers going to different buildings and individual homes.

The splitters are designated as [n: For downstream trafficthe traffic multiplexing functions are centralized in OLT. The optical time domain reflectometer is a commonly used test instrument in the construction and maintenance of optical cable lines.

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Key Technologies of GPON:GEM | FTTH & Triple Play Broadband equipment

PON system may be symmetrical or asymmetrical. DBA allows upstream mehod to shrink and grow based on the distribution of upstream traffic loads. The GPON ODN, consisting of a single mode optical fiber and cable; the optical fiber ribbon cables, splices, optical connectors, passive optical splitters and passive branching components are very passive.

When an ONU has no information to send, upon receiving a grant from the OLT, it sends an idle cell upstream to indicate that its buffer is empty. Subscriber 3 in Figure 3 In the downstream direction, the OLT removes the outer tag or passes through the traffic to proper GEM port based meyhod the tag value and priority bits.

Key Technologies of GPON:GEM

One of the basic requirements of an optical system is to provide components with sufficient capacity to extend the optical signal to the expected range. Constant length frames facilitate QoS for time-sensitive applications.

In the upstream direction, it is used to bear the service traffic. The Psync field indicates beginning of the frame to the ONUs.

The Port ID ranges from 0 to