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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GPON Fundamentals – Knowledge Base

The BW map dictates the arrangement of the bursts within the frame and the allocation intervals within each burst. 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 on the tag value and priority bits.

It is the data transport scheme in the specified GPON transmission convergence layer. Each allocation interval is controlled by a specific allocation structure of the BW map.

At the ONT, the traffic is classified again and placed into appropriate queues for each U interface. 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.

The bandwidth allocations to different Alloc-IDs are multiplexed in time as specified by the OLT in the bandwidth maps transmitted downstream. It is allocated by OLT i. A traffic bearing object within an ONT that represents a group of logical connections, and is treated as a single entity for the purpose of upstream bandwidth assignment on the PON.


The optical time domain reflectometer is a commonly used test instrument in the construction and maintenance of optical cable lines. Both T-CONT are of guaranteed bandwidth types and mainly used for video services and data services of higher priorities. Figure 4 shows a detailed downstream GTS frame format. GPON supports triple-play services, high-bandwidth, long reach upto 20kmetc. ONU management and control For example, Un-fragmented Ethernet frame as shown in the following illustration. However, it avoids large overhead by allowing variable length frames.

This identifier is assigned by OLT upon creation of a new channel and is only valid during the entire life-cycle of the channel.


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. In the upstream direction, mtehod is used to bear the service traffic. The basic requirement when selecting In some existing CATV operator network or some telecom upgrading projects eg The GEM channels carry variable-length Ethernet frames.

Encapsultion V reference point represents the network-facing interface of the OLT. The downstream transmission, i.


The optical paths can vary between 2 to 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 GPON ODN, consisting of a single mode optical fiber and cable; the methdo fiber ribbon cables, splices, optical connectors, passive optical splitters and passive branching components are very passive.

GEM | GPON Encapsulation Method | Glossary

encapsulahion To break down the bandwidth hurdle of the access over twisted pair cables, it supports high-bandwidth transmission. For downstream trafficthe traffic multiplexing functions are centralized in OLT.

Because the access network is shared, ONU upstream transmissions could collide if they were transmitted at random times. There are 2 types of GEM Channels: The optical network terminal ONTwhich is connected to the OLT at uplink side for service network interface, has meyhod user-network interface ports.

It is allocated by the OLT, i. One of the basic requirements of an optical system is to provide components with sufficient encapsulaton to extend the optical signal to the expected range. Each GEM port bears one kind of service traffic i.

The splitters are designated as [n: