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G.984.3-200902 Amd1

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G.984.3-200902 Amd1

    INTERNATIONAL TELECOMMUNICATION UNION

ITU-T G.984.3

    TELECOMMUNICATION Amendment 1 STANDARDIZATION SECTOR (02/2009) 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

     Gigabit-capable Passive Optical Networks

    (G-PON): Transmission convergence layer

    specification

    Amendment 1

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

    ? ITU 2009

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

    ITU-T Recommendation G.984.3 (03/2008)

    Gigabit-capable Passive Optical Networks (G-PON): Transmission

    convergence layer specification.

    Amendment 1 Summary

    This document contains the first Amendment to revised ITU-T Recommendation G.984.3 (03/2008)

    “GPON: Transmission convergence layer specification”. This Amendment:

     specifies the ONU Registration method;

     clarifies the definitions of Dying_Gasp and Deactivate_ONU-ID PLOAM messages;

     reconciles the description of PON alarms;

     adds a new Appendix clause addressing transmission of MPLS datagram using GPON

    Encapsulation Method;

     provides necessary clarifications to several standard items, including the use of the DBA

    reference model, the required number of supported reassembly buffers, and details of the

    key exchange.

    Rec. ITU-T G.984.3 (2008)/Amd.1 (02/2009) Prepublished version 1

ITU-T Recommendation G.984.3 (03/2008)

    Gigabit-capable Passive Optical Networks (G-PON): Transmission

    convergence layer specification.

    Amendment 1

    1 Introduction........................................................................................................................ 3 2 ONU Registration Method ................................................................................................ 3

    2.1 Clause 7.2.2......................................................................................................... 3

    2.2 Appendix IV. ...................................................................................................... 3

    2.3 New Appendix VI. ............................................................................................. 4

    3 PLOAM Messages ............................................................................................................ 5

    3.1 Definition of the Dying_Gasp. .......................................................................... 5

    3.2 Deactivate_ONU-ID message trigger ............................................................... 6

    3.3 POPUP Message function .................................................................................. 6

    4 GPON Alarms.................................................................................................................... 6

    4.1 Figure 11-1 Alarms ............................................................................................ 6

    4.2 Table 11.1.1 Items detected at OLT . ................................................................ 7

    4.3 Table 11.1.2 ONU Alarms. ................................................................................ 8

    5 MPLS over GEM............................................................................................................... 9 6 Maintenance Items ............................................................................................................ 9

    6.1 DBA reference model clarification. .................................................................. 9

    6.2 The number of reassembly buffers .................................................................... 10

    6.3 Key exchange clarification ................................................................................ 10

    Rec. ITU-T G.984.3 (2008)/Amd.1 (02/2009) Prepublished version 2

1 Introduction

    Amendment 1 to revised ITU-T Recommendation G.984.3 (03/2008) “GPON: Transmission

    convergence layer specification” contains several improvements and editorial corrections aimed at

    enhancing the readability and utility of the Recommendation. This Amendment:

     specifies the ONU Registration method;

     clarifies the definitions of Dying_Gasp and Deactivate_ONU-ID PLOAM messages; reconciles the description of PON alarms;

     adds a new Appendix clause addressing transmission of MPLS datagram using GPON

    Encapsulation Method;

     provides necessary clarifications to several standard items, including the use of the DBA

    reference model, the required number of supported reassembly buffers, and details of the

    key exchange.

    2 ONU Registration Method

    2.1 Clause 7.2.2

    Substitute the entire text of the Clause 7.2.2 with the following text:

    When an ONU is activated on the PON, it first cooperates with the OLT to attain

    synchronization, establish the physical layer OAM channel and achieve ranging. Because the

    PON is a point-to-multipoint system, it is then necessary to register the ONU to a particular

    subscriber. In most current business models, billing and privacy concerns imply that only after

    the ONU is properly registered can it be provisioned with a valid set of services.

    Appendix VI describes the ways in which an ONU may be registered to a subscriber.

2.2 Appendix IV.

    Substitute the initial paragraphs of the Appendix Clause IV.3 by the following text:

    The activation procedure described above is applicable for several types of ONU activation

    methods.

    In one activation method, the GPON protocol relies on the unique serial number of the ONU

    for identification and provisioning purposes. Some operators will use an operations system that

    pre-provisions ONUs based on serial number, the configured-SN activation method. In other

    situations, the serial numbers of the ONUs are unknown initially and therefore must be

    discovered. GPON allows for an automatic discovery method to accommodate this situation.

    An automatically discovered ONU may be associated with a subscriber through its PLOAM

    password, as described in Section VI.2 of Appendix VI. If the OLT supports registration ID

    activation, it can bring a discovered ONU into service based on its registration ID, and learn

    the ONU’s serial number for future use. Once the ONU is in service, the operations system can

    change the OLT mode to recognize the ONU by its serial number instead of, or in addition to, Rec. ITU-T G.984.3 (2008)/Amd.1 (02/2009) Prepublished version 3

    its PLOAM password during future ranging operations. The operations system may subsequently invoke the registration ID mode again for ONU repair or replacement.

    2.3 New Appendix VI.

    Provide a new informative Appendix at the end of Recommendation with the following text:

VI Appendix ONU Registration Methods

    When an ONU is activated on the PON, it first cooperates with the OLT to attain synchronization, establish the physical layer OAM channel and achieve ranging. Because the PON is a point-to-multipoint system, it is then necessary to register the ONU to a particular subscriber. In most current business models, billing and privacy concerns imply that only after the ONU is properly registered can it be provisioned with a valid set of services. There are several methods to register an ONU. An operator may wish to use one method for initial installation or replacement of an ONU, and a different method to recognize an existing ONU during subsequent activations. For example, authenticating a newly activated ONU by serial number allows for increased security during normal operation, whereas authenticating an ONU by PLOAM password allows for flexibility during installation and repair. In the latter case, the ONU being installed does not have to be specified in advance but can be selected by the technician from a pool of ONUs with suitable characteristics, thus simplifying the logistics of installation and repair.

    To support these registration methods, the OLT would have several modes, which may be governed by management action or by timed transitions. The details of OLT mode control are beyond the scope of this recommendation.

    VI.1 Authentication by serial number

    This method assumes that the association between the serial number (and, optionally, the PLOAM password) of the ONU and the specific subscriber is already established at the OLT either through pre-provisioning or in the course of previous activations. Because this method is the most straightforward in terms of PLOAM overhead, it is recommended for ONUs once their initial registration on the PON has been completed.

    In addition to the serial number, the PLOAM password, which is pre-provisioned (if fixed and known a priori) or learned at the previous activations (for example, if randomly generated), can be used for verification purposes.

    VI.2 Authentication by PLOAM password

    This method assumes that a registration ID is assigned to a subscriber at the management level, and provisioned both into the OLT and communicated to installation or repair personnel or even to the subscriber directly. There is assumed to be a method for entering the registration ID into the ONU in the field. Specification of such a method is beyond the scope of this recommendation.

    The registration ID populates the ONU’s PLOAM password, which is used by the OLT to recognize the ONU. The OLT may learn the value of the ONU’s serial number for possible subsequent use in serial number based authentication.

    VI.3 Other forms of authentication

    Additional ways to associate an ONU with a given subscriber, for example, the registration of

    Rec. ITU-T G.984.3 (2008)/Amd.1 (02/2009) Prepublished version 4

the ONU’s MAC address in a database, are not precluded. However, such possibilities are

    beyond the scope of this recommendation.

    3 PLOAM Messages

    3.1 Definition of the Dying_Gasp.

    1. Amend the Dying_Gasp message definition in Section 9.2.2 as follows:

    3 Dying_Gasp To inform the OLT that the The ONU At least 3 The OLT informs the

    ONU is powering off, is generates this times. Operation Support System,

    transitioning into a low power message when it optionally performing extra

    or battery conservation mode, experiences or diagnostics via the OMCC.

    or otherwise experiences or desires to The OLT should continue to desires to effectuate a change effectuate a provide bandwidth allocations in the powering conditions change in the to the ONU, but suppress and that may impact the ONU’s powering not report to the OSS the LOSi ability to respond to the conditions alarms that are raised should upstream bandwidth the ONU fail to respond to allocations. these allocations.

    This is to prevent the OLT The bandwidth allocation from issuing unnecessary patterns and the conditions to alarm reports and to prompt end the LOSi suppression extra diagnostic actions as depend on the reason deemed necessary. triggering the Dying_Gasp

    transmission, as determined by ONU issuing a Dying_Gasp is

    not required to actually power the OLT.

    off, and the OLT should not See Note below for an take the Dying_Gasp by itself example of such DG trigger-as the grounds to stop specific behaviour. bandwidth allocations to the

    given ONU.

2. Insert the following explanatory Note after the Table in Section 9.2.2:

    Consider as an example the OLT behaviour when upon receipt of a Dying Gasp, it concludes that

    the ONU is about to lose power without battery backup. If so is the case, the OLT initiates an

    implementation-specific timer defining the temporal scope of the Dying Gasp, and continues to

    provide the regular pattern of bandwidth allocations to the affected ONU. The temporal scope of the

    Dying Gasp can be expected to be much longer than the timer TO2. If a persistent LOSi condition (i.e., an LOSi that is not cleared by the directed POPUP process; see

    Section 11.1.1 for the definition of items detected at the OLT) occurs within the temporal scope of

    the Dying Gasp, the OLT should assume that the power has been lost indeed. Consequently, it may

    stop regular bandwidth allocations to the ONU and increase the frequency of the broadcast SN

    Requests. However, it does not issue a notification to the OSS and does not attempt to forcibly

    deactivate the ONU. If the OLT chooses to continue to provide allocations to the ONU (for

    example, providing targeted ranging allocations in support of a power saving behaviour), it should

    ignore any LOSi conditions up to the moment the ONU responds to such targeted allocation with a

    valid PLOAM message or announces itself with a contention-oriented Serial_Number_ONU

    PLOAM.

    Further consider a situation when the ONU that has submitted a Dying Gasp does not lose power. If

    within the temporal scope of the Dying Gasp it experiences an intermittent LOS condition, it enters

    Rec. ITU-T G.984.3 (2008)/Amd.1 (02/2009) Prepublished version 5

    the POPUP state (O6) in a usual way and can return to Operation state (O5) upon receipt of a directed POPUP message. If the LOS condition experienced by the ONU is persistent (i.e., the TO2 timer is let to expire), the ONU falls back to the Initial state (O1) and waits for clearing the LOS condition to repeat the activation routine. As a result of the LOS occurring within the temporal scope of the Dying Gasp, the OSS is not notified by the OLT of the LOSi condition associated with the given ONU.

3. Remove the note at the end Dying_Gasp format definition in Section 9.2.4.3:

    NOTE G.983.1 name of this message is R-INH.

    3.2 Deactivate_ONU-ID message trigger 1. In the Table of Section 9.2.1 Downstream Message Definition, in line 4, specify the Trigger for the Deactivate_ONU-ID message as follows:

    When any of the following alarm conditions are raised at the OLT: LOSi, (unless cleared by POPUP message or suppressed by prior receipt of a Dying_Gasp), LOFi, LOKi, LOAi, LOAMi, SFi, SUFi.

    3.3 POPUP Message function 1. In the Table of Section 9.2.1 Downstream Message Definition, in line 10, rephrase the Function column entry as follows:

    The OLT forces all the ONUs which are in POPUP state (O6) and have the LOS/LOF condition cleared to go from POPUP state (O6) to Ranging state (O4) or commanding a specific ONU to go directly to Operation state (O5).

4 GPON Alarms

    4.1 Figure 11-1 Alarms

    Add TIW(i), TIA, LOK(i); remove LCDA, LCDA(i), add index to RDI(i), REI(i).

Rec. ITU-T G.984.3 (2008)/Amd.1 (02/2009) Prepublished version 6

4.2 Table 11.1.1 Items detected at OLT .

    1. In the LOSi row, modify the description in the Actions column as follows:

    If the OLT supports POPUP, then generate three POPUP messages.

    If the LOSi alarming is not suppressed due to the prior Dying Gasp message and either the OLT

    does not support POPUP or the LOSi condition is not cleared after the three POPUP messages, then

    generate Loss_of_PHY_Layer_i notification and send three Deactivate_ONU-ID messages to the

    ONUi.

    2. In the DOWi row, change the first sentence in the Detection Condition column from An ONU transmission is received at an unexpected place within the US virtual frame” to: In N sequential bursts from the given ONU the transmission drift exceeds the lower of two

    specified drift thresholds. This condition indicates that while the transmission phase has shifted, it

    remains correctable via EqD update.

    3. In the TIWi row, change the description in the Detection Condition column to:

    Rec. ITU-T G.984.3 (2008)/Amd.1 (02/2009) Prepublished version 7

In N sequential bursts from the given ONU the transmission drift exceeds the upper of two

    specified drift thresholds. This condition indicates that either the drift is occurring critically fast, or

    the attempt to correct the transmission phase through the EqD update has failed.

    4. In the TIWi row, add the following sentence to the Actions column (appears in the description,

    section 10.3.5) :

    Send Deactivate_ONU-ID message 3 times.

    5. In the DGi row, modify the contents of the Action column as follows:

    Notify the OSS of the Dying Gasp received. Optionally perform extra diagnostics via the OMCC.

    While continuing to provide bandwidth allocations to the ONU, suppress and not report to the OSS

    the LOSi alarms that are raised should the ONU fail to respond to these allocations.

    6. In the DGi row, the contents of the Cancellation Condition column as follows:

    Depends on the DG trigger as determined by the OLT. For example, cancel DGi upon expiration of

    the DG temporal scope timer, if no LOSi occurs, or upon receipt of a valid PLOAM, if LOSi does

    occur.

    7. In the LOAMi row, modify the description in the Detection Condition column as follows (failure

    to send a standalone PLOAM qualifies for LOSi; also cf. MEMi):

    When in response to three consecutive PLOAM allocations, the ONU transmits the PLOAM field

    that has incorrect CRC or does not parse into a valid PLOAM message.

    8. Rephrase the contents of Actions column in the rows LOFi, SFi, LOAi, LOAMi, LOKi as follows:

    Generate Loss_of_PHY_Layer_i notification and send three Deactivate_ONU-ID messages to the

    ONUi.

4.3 Table 11.1.2 ONU Alarms.

    1. Add Loss_of_PHY_layer indication to the SF row.

SF Signal When the downstream Generate Set inactive when ?yFailed Loss_of_phy_layer the downstream BER becomes ? 10, this ?(y+1) notification. BER is < 10 state is entered. Y is

    configurable in the range

    of 5 to 8

    2. Add a note after the table.

    Note that, strictly speaking, switching off the ONU’s laser is a result of the ONU activation

    state transition caused by the alarm, rather than by the alarm itself.

Rec. ITU-T G.984.3 (2008)/Amd.1 (02/2009) Prepublished version 8

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