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Draft new Recommendation G9871 10 Gigabit-capable Passive

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Draft new Recommendation G9871 10 Gigabit-capable Passive

INTERNATIONAL TELECOMMUNICATION UNION

ITU-T G.987.1

    TELECOMMUNICATION (01/2010) STANDARDIZATION SECTOR

    OF ITU

    SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS

    Digital sections and digital line system Optical line

    systems for local and access networks

     10 Gigabit-capable Passive Optical Network (XG-PON): General Requirements

    CAUTION !

    PREPUBLISHED RECOMMENDATION

    This prepublication is an unedited version of a recently approved Recommendation.

    It will be replaced by the published version after editing. Therefore, there will be

    differences between this prepublication and the published version.

    FOREWORD

    The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. 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.

    The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics.

    The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC.

    NOTE

    In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency.

    Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party.

    INTELLECTUAL PROPERTY RIGHTS

    ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. 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/had not] received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged

    http://www.itu.int/ITU-T/ipr/. to consult the TSB patent database at

     ITU 2010

    All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU.

Recommendation ITU-T G.987.1

    10 Gigabit-capable Passive Optical Network (XG-PON):

    General Requirements

    1 Scope

    This Recommendation addresses the general requirements of 10 Gigabit-capable Passive Optical Network (XG-PON) systems, in order to guide and motivate the physical layer and the transmission convergence layer specifications. The general requirements include examples of services, User Network Interfaces (UNI) and Service Node Interfaces (SNI), as well as the principal deployment configurations that are requested by network operators. This Recommendation also includes the system and operational requirements to meet the needs of supporting various business and residential applications.

    As much as possible, this Recommendation maintains characteristics from [ITU-T G.982], [ITU-T G.983], and [ITU-T G.984] series of Recommendations. This is to promote backward compatibility with existing Optical Distribution Networks (ODN) that complies with those Recommendations. Furthermore, this recommendation provides a mechanism that enables seamless subscriber migration from Gigabit PON (Generic term to represent both G-PON and GE-PON) to XGPON

    using WDM defined in the G.984 series.

    There are two flavours of XG-PONs based on the upstream line rate: XG-PON1 featuring a 2.5Gbit/s upstream path and XG-PON2 featuring a 10Gbit/s one. The initial phase of this specification only addresses XG-PON1. XG-PON2 will be addressed at later phase when the technology becomes more mature.

    2 References

    The following ITU-T Recommendations and other references contain provisions, which, through reference in this text, constitute provisions of this Recommendation. 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. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation [ITU-T G.652] ITU-T Recommendation G.652 (2005), Characteristics of a single-mode

    optical fibre cable.

    [ITU-T G.657] ITU-T Recommendation G.657 (2006), Characteristics of a bending loss

    insensitive single mode optical fibre and cable for the access network. [ITU-T G.902] ITU-T Recommendation G.902 (1995), Framework Recommendation on

    functional access networks (AN) Architecture and functions, access types,

    management and service node aspects.

     [ITU-T G.982] ITU-T Recommendation G.982 (1996), Optical access networks to support

    services up to the ISDN primary rate or equivalent bit rates.

    [ITU-T G.983.1] ITU-T Recommendation G.983.1 (2005), Broadband optical access systems

    based on Passive Optical Networks (PON).

    Rec. ITU-T G.987.1 (01/2010) Prepublished version 1

[ITU-T G.983.2] ITU-T Recommendation G.983.2 (2005), ONT management and control

    interface specification for B-PON.

    [ITU-T G.983.3] ITU-T Recommendation G.983.3 (2001), A broadband optical access system

    with increased service capability by wavelength allocation.

    [ITU-T G.984.1] ITU-T Recommendation G.984.1 (2008), Gigabit-capable Passive Optical

    Networks (GPON): General characteristics.

    [ITU-T G.984.2] ITU-T Recommendation G.984.2 (2008), Gigabit-capable Passive Optical

    Networks (GPON): Physical Media Dependent (PMD) layer specifications. [ITU-T G.984.3] ITU-T Recommendation G.984.3 (2008), Gigabit-capable Passive Optical

    Networks (GPON): Transmission convergence layer specification.

    [ITU-T G.984.4] ITU-T Recommendation G.984.4 (2008), Gigabit-capable Passive Optical

    Networks (GPON): ONT management and control interface specification. [ITU-T G.984.5] ITU-T Recommendation G.984.5 (2007), Gigabit-capable Passive Optical

    Networks (GPON): Enhancement band for Gigabit-capable Passive Optical

    Networks.

    [ITU-T G.984.5Am1] ITU-T Recommendation G.984.5 Am1 (2009), Gigabit-capable Passive

    Optical Networks (G-PON): Enhancement band. Amendment 1.

     [ITU-T G.808.1] ITU-T Recommendation G.808.1 (2006), Generic protection switching

    Linear trail and subnetwork protection.

    [ITU-T G.984.6] ITU-T Recommendation G.984.6 (2008), Gigabit-capable Passive Optical

    Networks (GPON): GPON optical reach extension (G.984.re).

    [ITU-T Y.2201] ITU-T Recommendation Y.2201 (2007), NGN release 1 requirements [ITU-T G.810] ITU-T Recommendation G.810 (1996), Definitions and terminology for

    synchronization networks

    [ITU-T G.813] ITU-T Recommendation G.813 (2003), Timing characteristics of SDH

    equipment slave clocks (SEC)

    [ITU-T G.703] ITU-T Recommendation G.703 (2008), Physical/electrical characteristics of

    hierarchical digital interfaces

    [ITU-T G.8261] ITU-T Recommendation G.8261 (2008), Timing and synchronization aspects

    in packet networks

    [ITU-T G.8262] ITU-T Recommendation G.8262 (2008), Timing characteristics of synchronous

    Ethernet equipment slave clock (EEC)

    [ITU-T G.Sup45] ITU-T Series G Supplement45 (2009), Means and impact of GPON power

    saving. White Paper

    [ITU-T G.987] ITU-T Recommendation G.987 (2009), G.987 definitions, abbreviations and

    acronyms

    [ITU-T G.987.2] ITU-T Recommendation G.987.2 (2009), 10-Gigabit-capable Passive Optical

    Networks (XG-PON): Physical Media Dependent (PMD) layer specification [ITU-T Y.2001] ITU-T Recommendation Y.2001 (12/2004), General overview of NGN. [ITU-T Y.1731] ITU-T Recommendation Y.1731 (02/2008), OAM functions and mechanisms

    for Ethernet based networks.

    Rec. ITU-T G.987.1 (01/2010) Prepublished version 2

    [ITU-T J.185] ITU-T Recommendation J.185 (02/2002), Transmission equipment for

    transferring multi-channel television signals over optical access networks by

    FM conversion.

    [ITU-T J.186] ITU-T Recommendation J.186 (06/2003), Transmission equipment for multi-

    hannel television signals over optical access networks by sub-carrier c

    multiplexing (SCM).

    [IEEE 1588] IEEE 1588-2008 (2008), IEEE Standard for a Precision Clock Synchronization

    Protocol for Networked Measurement and Control Systems

    [DSLF TR-156] DSL Forum (also known as the Broadband Forum) TR-156 (2008) Using

    GPON Access in the context of TR-101

    [MEF 10.1] MEF 10.1 (2006), Ethernet Service Attributes Phase 2

    3 Definitions

    See [ITU-T G.987], clause 3.

    4 Abbreviations and Acronyms

    See [ITU-T G.987], clause 4.

    5 Architecture of the optical access network

    5.1 Network architecture

    The optical section of a local access network system can be either active or passive and its architecture can be either point-to-point or point-to-multipoint. Figure 5-1 shows the considered architectures, which range from Fibre to the Home (FTTH), Fibre to the Cell sites (FTTCell), Fibre to the Building/Curb (FTTB/C), to the Fibre to the Cabinet (FTTCab), etc. The Optical Distribution Network (ODN) is common to all architectures shown in Figure 5-1; hence the commonality of this system has the potential to generate large worldwide volumes.

Rec. ITU-T G.987.1 (01/2010) Prepublished version 3

    Figure 5-1 - Network Architecture

    Note: An ONU supporting FTTH has been commonly referred to as ONT (See [ITU-T G.987]) The differences among these FTTx options are mainly due to the different services supported and the different locations of the ONUs rather than the ODN itself, so they can be treated as one in this Recommendation. It must be noted that a single OLT optical interface might accommodate a combination of several scenarios described hereafter.

    XG-PON should extend the G.984.6 reach extenders capability, inherited from the G.984 recommendations series, to produce extra optical budget to achieve longer distances and/or additional passive split.

    5.1.1 FTTB scenario

    The FTTB scenario is divided into two scenarios, one for multi-dwelling units (MDU) and the other for businesses or mixed environments (MTU). Each scenario has the following service categories: 5.1.1.1 FTTB for MDU served residential users

     Asymmetric broadband services (e.g., IPTV, digital broadcast services, VOD, file

    download, etc.).

     Symmetric broadband services (e.g., content broadcast, e-mail, file exchange, distance

    learning, telemedicine, online-game, etc.).

     POTS - The access network must be able to provide, in a flexible way, narrow-band

    telephone services with appropriate using either emulation (complete replication of a legacy

    service) or simulation (providing a service that is almost the same as the legacy service). 5.1.1.2 FTTB for MTU served business users

     Symmetric broadband services (e.g., group software, content broadcast, e-mail, file

    exchange, etc.).

    Rec. ITU-T G.987.1 (01/2010) Prepublished version 4

     POTS - The access network must be able to provide, in a flexible way, narrow-band

    telephone services using either emulation (complete replication of a legacy service) or

    simulation (providing a service that is almost the same as the legacy service). Private line. The access network must be able to provide, in a flexible way, private line

    services at several rates.

    5.1.2 FTTC and FTTCab scenario

    Within this scenario, the following service categories have been considered: Asymmetric broadband services (e.g., IPTV, digital broadcast services, VoD, file

    download, online-game, etc.).

     Symmetric broadband services (e.g., content broadcast, e-mail, file exchange, distance

    learning, telemedicine, etc.).

     POTS - The access network must be able to provide, in a flexible way, narrow-band

    telephone services using either emulation (complete replication of a legacy service) or

    simulation (providing a service that is almost the same as the legacy service). xDSL backhaul.

    5.1.3 FTTH scenario

    Within this scenario, the following service categories have been considered: Asymmetric broadband services (e.g., IPTV, digital broadcast services, VOD, file

    download, etc.).

     Symmetric broadband services (e.g., content broadcast, e-mail, file exchange, distance

    learning, telemedicine, online-game, etc.).

     POTS - The access network must be able to provide, in a flexible way, narrow-band

    telephone services using either emulation (complete replication of a legacy service) or

    simulation (providing a service that is almost the same as the legacy service). 5.1.4 FTTO scenario

    FTTO addresses business ONU dedicated to a small business customer. Within this scenario, the following service categories have been considered:

     Symmetric broadband services (e.g., group software, content broadcast, e-mail, file

    exchange, etc.).

     POTS - The access network must be able to provide, in a flexible way, narrow-band

    telephone services using either emulation (complete replication of a legacy service) or

    simulation (providing a service that is almost the same as the legacy service). Private line. The access network must be able to provide, in a flexible way, private line

    services at several rates.

    5.1.5 FTTCell wireless scenario

    Within this scenario, the ONU will be called CBU and will have to offer connectivity to wireless base stations:

    - Symmetric TDM services (e.g., 2G cell site backhaul)

    - Symmetric/Asymmetric packet based broadband services (e.g., 3G/4G cell site backhaul)

    - Hot spots

    Rec. ITU-T G.987.1 (01/2010) Prepublished version 5

    Within this scenario, the ONU will be called CBU and will have to offer connectivity to wireless base stations.

    Figure 5-2 represents exemplary scenarios of XG-PON applications.

    XG-PON

    FTTCellCBU

    BusinessFTTBMTU

    XG-PON FTTOSBUOLT

    FTTHSFU

    ResidentialAggregation SwitchFTTBMDU

    XG-PON OLTONUFTTCurb/Cab

    - Figure 5-2 - A summary of some XG-PON scenarios

5.1.6 Environment conditions in outdoor scenarios

    For supporting the wide range of scenarios and applications, optical parameters for the OLT and the ONU should be determined to allow an outdoor operation.

    5.2 Reference configuration

    A high level and simple reference configuration of XG-PON is depicted in Figure 5-3, which shows very similar high level reference configuration as G.983 and G.984 series. Rec. ITU-T G.987.1 (01/2010) Prepublished version 6

    Access Network management

    functions

    ONU

    R/S S/R

    Service Node ODN OLT functions

    SNI ONU (V) Reference

    AF point

    (a) Reference point UNI

     (T) Reference point

     User side Network side

    Figure 5-3 - High Level Reference Configuration of XG-PON

In addition to Figure 5-3, when XG-PON is deployed with a RF video overlay service, the ODN can

    use a WDM device or an optical coupler/splitter to combine XG-PON and RF video signal. The

    coupler/splitter can optionally be used to provide a split at the Central Office (CO). Such

    architectures are depicted in 错误;未找到引用源。Error! Reference source not found. and

    误;未找到引用源。Error! Reference source not found..

Rec. ITU-T G.987.1 (01/2010) Prepublished version 7

    Figure 5-4 - Reference access network architecture

    Figure 5-4 depicts generic optical access network (OAN) reference architecture that applies to the XG-PON. It includes an OLT, ONUs and an Optical Distribution Network (ODN) between them. As shown in Figure 5-4, an XG-PON ODN can consist of a single passive optical distribution segment (ODS), or a group of passive ODSs interconnected with reach extenders (REs) [ITU-T G.987].

    5.2.1 ODN architectures

    There can be several types of ODN architectures to achieve coexistence between XG-PON1 or XG-PON2 and additional services such as G-PON and video distribution services. Figure 5-5 and Figure 5-6 are reference diagrams of optical access network architectures. The figures assume that wavelength blocking filters (WBF) are used when XG-PON (1 or 2), G-PON and video are shared within the same ODN.

    Note that these diagrams simply provide reference configurations of the ODN and WBF, and are not intended to limit future designs and implementations. In addition, the coexistence of XG-PON1 and XG-PON2 is outside the scope of this clause since this would not affect WDM configuration. Rec. ITU-T G.987.1 (01/2010) Prepublished version 8

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