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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There are 2 types of GEM Channels: 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. There are three categories or classes of components, which are based on power and sensitivity.

This is shown in figure 2. Figure 5 shows upstream GTC frame format.

It is then transmitted in the downstream direction to the PON interface by using a scheduler. It is allocated by OLT i. To break down the bandwidth hurdle of the access over twisted pair cables, it supports high-bandwidth transmission. A scheduler is used to transmit frames to the U interface. GFP allows direct encapsulation of variable length packets without repeating the encapsulation overhead on a regular basis.



GEM supports fragmentation and reassembly. The GEM channels carry variable-length Ethernet frames. It is allocated by OLT i.

Constant length frames facilitate QoS for time-sensitive applications.

PON and fiber infrastructure can also be used for supporting any one-way distributive service. However, it avoids large overhead by allowing variable length frames. It has constant-size HEC-protected header.

The parity bit is set to provide an even number of 1s within the header. Link protection is also known as link aggregationwhich can protect the link and the same time, it can aggregate the traffic as well. In some existing CATV operator network or some telecom upgrading projects encapsulatiom The V reference point represents the network-facing interface of the OLT.

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

Downstream Traffic Management Figure 6 shows a sample model of downstream traffic management. The downstream transmission, i. It is a recipient of upstream bandwidth allocations within the ONU. The ODN optical splitters divide the single fiber into multiple fibers going to different buildings and individual homes.

Key Technologies of GPON:GEM

This T-CONT is of best-effort type and mainly used for data services such as Internet and services of low priority which do not require high bandwidth. 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.


A grant is permission to use a defined interval of time for upstream transmission. GEM provides a connection-oriented, variable-length framing mechanism for transport of data services over the passive optical network PON. The downstream GTC frame provides the common time reference for the PON and the common control signaling for the upstream.

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. GPON supports triple-play services, high-bandwidth, long reach upto 20kmetc.

For example — Video at a different wavelength. The Optical Splitter merely divides the optical power into N separate paths to the users. In the upstream direction, it is used to bear the service traffic.

DBA allows upstream timeslots to shrink and grow based on the distribution of upstream traffic loads. Type 2 and Type 3: The bandwidth allocations to different Alloc-IDs are multiplexed in time as specified by the OLT in the bandwidth maps transmitted downstream.

The splitters are designated as [n:

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