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ITU-T G. ITU-T G. This Recommendation proposes the general characteristics for GPON based on operators' service requirements. This Recommendation aims to improve on the G. In order to insure maximal continuity with existing systems and optical fibre infrastructure, this Recommendation maintains some requirements of ITU-T Rec. ITU-T Rec. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis.
NOTE In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency.
ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process.
As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database.
ITU All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Architecture of the optical access network Services, user network interface and service node interface Bit rate Logical reach Physical reach Differential fibre distance Maximum mean signal transfer delay Split ratio Service overlay Protection on the PON section Appendix II — Bibliography Also, this Recommendation shows the principal deployment configuration.
At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below.
The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation   ITU-T Recommendation G. For convenience, the main definitions related to the GPON service requirements are reported in this clause. It utilizes passive optical components. Service is described by the name that is clearly recognized by everyone, regardless of whether it is a frame structure name or a general name. The Optical Access Network OAN is common to all architectures shown in Figure 1, hence the commonality of this system has the potential to generate large worldwide volumes.
Each scenario has the following service categories: 5. The access network must be able to provide, in a flexible way, narrowband telephone services with appropriate timing for the introduction. The access network must be able to provide, in a flexible way, narrowband telephone services with the appropriate timing for the introduction.
The access network must be able to provide, in a flexible way, private line services at several rates. FTTH scenario Within this scenario, the following service categories have been considered: — Asymmetric broadband services e. If WDM is not used, these points are not necessary. What specific services should be provided is clearer to some operators than to others and depends heavily on the particular regulatory conditions of each operators' markets, as well as on the own markets potential.
How these services are delivered in a cost effective way is a function not only of legal conditions, but also of factors including existing telecommunications infrastructure, dwelling distribution and residential and business customers mix.
The examples of services are described in clause I. The examples of UNI are described in clause I. In GPON, the maximum logical reach is defined as 60 km. In GPON, two options are defined for the physical reach: 10 km and 20 km. Specifically, GPON system must have a maximum mean signal transfer delay time of less than 1.
However, a larger split ratio implies greater optical splitting which creates the need for an increased power budget to support the physical reach. Split ratios of up to are realistic for the physical layer given current technology. However, anticipating the continued evolution of optical modules, the TC layer must consider split ratios up to However, protection shall be considered as an optional mechanism because its implementation depends on the realization of economical systems.
This clause presents some possible duplex configurations and related requirements as examples of protected GPON systems. In addition, the required OAM message for protection is mentioned. The first one is triggered by fault detection, such as loss of signal, loss of frame, signal degrade BER becomes worse than the predetermined threshold , and so on.
The second one is activated by administrative events, such as fibre rerouting, fibre replacement, etc.
Both types should be possible in the GPON system, if required, even though they are optional functions. The control protocols for each configuration should be specified independently from one another. Also, in Figure 4b, no switching protocol is required since the switching is carried out only in the OLT. In this configuration, recovery from failure at any point is possible by switching to the standby facilities.
Therefore, the full duplex cost enables a high reliability. Type D: If the ONUs are installed in the customer buildings, the in-house wiring may or may not be duplexed. Additionally, if each ONU is owned by a different user, the reliability requirement depends on each user and only a limited number of ONUs may have the duplex configuration.
Based on this consideration, the last configuration Figure 4d permits a partial duplexing on the ONU side. However, all the connections between the service node and the terminal equipment should be held after this fibre switching.
In this case, signal loss or even frame loss is, in general, inevitable in the switching period. However, all the connections supported between the service node and the terminal equipment should be held after this switching.
In addition, hitless switching without frame loss is also possible in this configuration. Type D: The characteristics of this type are the same as Type B. Both automatic protection switching and forced switching are possible in the GPON system, if required, even though they are optional functions. All the configuration examples of All the connections supported between the service node and the terminal equipment should be held after switching. Regarding the last requirement, one implementation of the POTS service node exchange requires the frame loss period to be less than ms.
If the frame loss period becomes longer than that, the service node disconnects the call, and the call set-up is required again after the protection switching. The field mapping of the OAM frame for the protection will be required to be defined.
Table I. Comply with IEEE Mean signal transfer delay time between T-V or a -V should be less than 1. If echo cancellation is used in the network, the mean signal transfer delay time between T-V or a -V on the PON-based system may be longer, provided End-to-End transfer delay requirements are met. Synchronize with the network's 8 kHz clock. Signal on the T reference point and V reference point must be continuous. E1 Bearer rate is 2. Bearer rate is Deliver with same quality as class.
It is not meaningful in itself, but it is useful in visualizing the services. NOTE 3 — The column labeled "Service" shows which services can be supported by the physical interface.
In recent years, the requirement for data transfer capacity and reliable networks have increased. Reliability of communication networks is an increasingly important parameter, and accordingly continuous operation of optical networks in case of breakage of fibers or malfunctioning nodes or devices is desired. These are:. So far, the interest in protection switching in the GPON community has been limited since typical deployment scenarios support a maximum of 64 split on 20 km reach, i.
US8917990B2 - Fast protection scheme for passive optical network - Google Patents
Committed to connecting the world. ITU-T Recommendations. ITU-T G. This Recommendation proposes the general characteristics for GPON based on operators' service requirements. Editions Related Supplement s Related technical papers and reports.