1、COVERING NOTE GENERAL SECRETARIAT OF THE INTERNATIONAL TELECOMMUNICATION UNION Geneva, 16 March 2006 ITU -TELECOMMUNICATION STANDARDIZATION SECTOR Subject: Erratum 1 (03/2006) to ITU-T Recommendation G.983.1 (01/2005), Broadband optical access systems based on Passive Optical Networks (PON) In claus
2、e W3.1 Configuration examples“, mod it would include video and distributive services. This Recommendation describes characteristics of an Optical Access Network (OAN) with the capability of transporting various services between the user-network interface and the Service node interface. The OAN descr
3、ibed in this Recommendation should enable the network operator to provide a flexible upgrade to meet future customer requirements, in particular in the area of the Optical Distribution Network (ODN). The ODN considered is based on point-to-multipoint tree and branch option. This Recommendation conce
4、ntrates on the fibre issues; the copper issues of hybrid systems are described elsewhere, e.g., xDSL standardization. This Recommendation covers issues between the Service node interface and the User network. Although this Recommendation concentrates on issues relating to ATM over a passive optical
5、network, other solutions are not precluded. This Recommendation proposes the physical layer requirements and specifications for the physical media dependent layer, the TC layer and the ranging protocol of an ATM-based Broadband Passive Optical Network (B-PON). This Recommendation is part of the G.98
6、3.x series. The other major components of this series include: G.983.2 (2002), ONT management and control interface specification for B-PON. G.983.3 (2001), A broadband optical access system with increased service capability by G.983.4 (2001), A broadband optical access system with increased service
7、 capability using G.983.5 (2001), A broadband optical access system with enhanced survivability. wavelength allocation. dynamic bandwidth assignment. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions
8、of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations
9、 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. i 2 ITU-T Recommendation G.652 (2003), Characteristics o
10、f a single-mode opticalfibre cable. ITU-T Recommendation G.67 1 (2005), Transmission characteristics of optical components and subsystems. ITU-T Rec. G.983.1(01/2005) 1 ITU-T Recommendation G.783 (2004), Characteristics of synchronous digital hierarchy (SDH) equipment functional blocks. ITU-T Recomm
11、endation G.902 (1 995), Framework Recommendation on functional access networks (m) -Architecture and functions, access types, management and service node aspects. ITU-T Recommendation G.957 (1999), Optical inter$aces for equipments and systems relating to the synchronous digital hierarchy. ITU-T Rec
12、ommendation G.958 (1994), Digital line systems based on the synchronous digital hierarchy for use on optical fibre cables. ITU-T Recommendation G.982 (1996), Optical access networks to support services up to the ISDNprimary rate or equivalent bit rates. ITU-T Recommendation 1.32 1 (1 99 1 ), B-ISDNp
13、rotocol reference model and its application. ITU-T Recommendation 1.326 (2003), Functional architecture of transport networks based on ATM. ITU-T Recommendation 1.356 (2000), B-ISDN ATM layer cell transfer performance. ITU-T Recommendation 1.361 (1 999), B-ISDN ATM layer specijkation. ITU-T Recommen
14、dation 1.432.1 (1999), B-ISDN user-network interface -Physical layer specijkation: General characteristics. ITU-T Recommendation 1.61 O (1 999), B-ISDN operation and maintenance principles and functions. ITU-T Recommendation 1.732 (2000), Functional characteristics of ATM equipment. Federal Informat
15、ion Processing Standard No. 197 (2001), Advanced Encryption Standard (AES), National Institute of Standards and Technology. ITU-T Recommendation G.983.2 (2002), ONT management and control interface specijkation for B-PON. ITU-T Recommendation G.983.3 (2001), A broadband optical access system with in
16、creased service capability by wavelength allocation. ITU-T Recommendation G.983.4 (2001), A broadband optical access system with increased service capability using dynamic bandwidth assignment. ITU-T Recommendation G.983.5 (2002), A broadband optical access system with enhanced survivability. Abbrev
17、iations This Recommendation uses the following abbreviations: AES Advanced Encryption Standard AF Adaptation Function APS Automatic Protection Switching ATM Asynchronous Transfer Mode BER Bit Error Ratio BIP Bit Interleaved Parity B-ISDN 2 ITU-T Rec. G.983.1(01/2005) Broadband Integrated Services Di
18、gital Network B-PON CID CPE CRC DSL ECB E/O FP-LD FTTB/C FTTCab FTTH HEC IEC ISDN LAN LCD LCF LSB LT MAC MLM MSB NRZ NT O/E OAM OAN ODF ODN OLT OMCC OMCI ONT ONU Ops ORL PLOAM Broadband Passive Optical Network Consecutive Identical Digit Cell Phase Error Cyclic Redundancy Check Digital Subscriber Li
19、ne Electronic Code Book Electrical/Optical Fabry-Perot Laser Diode Fibre to the BuildingKurb Fibre to the Cabinet Fibre to the Home Header Error Control International Electrotechnical Commission Integrated Services Digital Network Local Area Network Loss of Cell Delineation Laser Control Field Least
20、 Significant Bit Line Terminal Media Access Control Multi-Longitudinal Mode Most Significant Bit Non Return to Zero Network Termination Optical/Electrical Operations, Administration and Maintenance Optical Access Network Optical Distribution Frame Optical Distribution Network Optical Line Terminatio
21、n ONT Management and Control Channel ONT Management and Control Interface Optical Network Termination Optical Network Unit Operations System Optical Return Loss Physical Layer OAM ITU-T Rec. G.983.1(01/2005) 3 PON PRBS PST PSTN QOS RAU RMS RXCF SDH SLM SN SNI TC TDMA u1 UNI UPC vc VP VPI WDM Passive
22、 Optical Network Pseudo-Random Bit Sequence PON Section Trace Public Switched Telephone Network Quality of Service Request Access Unit Root Mean Square Receiver Control Field Synchronous Digital Hierarchy Single-Longitudinal Mode Serial Number Service Node Interface Transmission Convergence Time Div
23、ision Multiple Access Unit Interval User Network Interface Usage Parameter Control Virtual Channel Virtual Path Virtual Path Identifier Wavelength Division Multiplexing 4 Definitions This Recommendation defines the following terms: 4.0 Broadband PON: A term used to refer to the entire system describ
24、ed by the G.983.x family of ITU-T Recommendations. This includes a wide range of broadband services, and goes beyond ATM access. For this reason, B-PON supersedes the older usage of ATM-PON. 4.1 churning: A function which can be applied to the downstream user data fi-om an OLT to its ONUs. Churning
25、provides the necessary function of data scrambling and offers a low level of protection for data confidentiality. It is installed at the TC layer of the ATM-PON system and can be activated for point-to-point downstream connections. 4.2 diplex working: Bidirectional communication using a different wa
26、velength for each direction of transmission over a single fibre. 4.3 duplex working: Bidirectional communication using the same wavelength for both directions of transmission over a single fibre. 4.4 grant: OLT controls each upstream transmission fi-om ONUs by sending a permission. Grant is a permis
27、sion to transmit an upstream cell of each ONU when an ONU receives own grant. 4.5 logical reach: Defined as the maximum length that can be achieved for a particular transmission system independent of optical budget. 4 ITU-T Rec. G.983.1(01/2005) 4.6 mean signal transfer delay: The average upstream a
28、nd downstream values between reference points “V“ and “T“, a given value is determined by measuring round-trip delay, then dividing by 2. 4.7 optical access network (OAN): The set of access links sharing the same network-side interfaces and supported by optical access transmission systems. The OAN m
29、ay include a number of ODNs connected to the same OLT. 4.8 optical distribution network (ODN): An ODN provides the optical transmission means fi-om the OLT towards the users, and vice versa. It utilizes passive optical components. 4.9 optical line termination (OLT): An OLT provides the network-side
30、interface of the OAN, and is connected to one or more ODNs. 4.10 ONT management and control channel (OMCC): The communications circuit connecting the control function of the OLT to that of the ONT. The protocol used for this is defined in ITU-T Rec. G.983.2. 4.11 ONT management and control interface
31、 (OMCI): The interface defined in ITU-T Rec. G.983.2 that provides a uniform method for managing faults, configuration, performance, and security on ONTs. 4.12 optical network termination (ONT): An ONU used for FTTH and includes the User Port function. This Recommendation uses the term “ONU“ to refe
32、r to both ONTs and ONUs. Any reference to ONUs includes ONTs as well within this Recommendation. 4.13 optical network unit (ONU): An ONU provides (directly or remotely) the user-side interface of the OAN, and is connected to the ODN. This Recommendation uses the term “ONU“ to refer to both ONTs and
33、ONUs. Any reference to ONUs includes ONTs as well within this Recommendation. 4.14 ranging: It is necessary to transmit an upstream cell without cell collision in this system. Ranging is a function to measure the logical distance between each ONU and OLT and decide the transmission timing when each
34、ONU receives a grant. 4.15 service port function: The Service Port Function (SPF) adapts the requirements defined for a specific SNI to the common bearers handling and selects the relevant information for treatment in the AN system management function. 4.16 time division multiple access (TDMA): Tran
35、smission technique involving the multiplexing of many time slots onto the same time payload. 4.17 user port function: The User Port Function (UPF) adapts the specific UNI requirements to the core and management functions. The AN may support a number of different accesses and user network interfaces
36、which require specific functions according to the relevant interface specification and the access bearer capability requirements, i.e., bearers for information transfer and protocols. 4.18 verification: It is possible for a malicious user to masquerade as other ONU and use the network if the user kn
37、ows that the ONU is off power. Verification is a function to check whether the connected ONU is masqueraded by a malicious user. 4.19 wavelength division multiplexing (WDM): Bidirectional multiplexing using different optical wavelength for up and downstream signals. 5 Architecture of the optical acc
38、ess network 5.1 Network architecture The optical section of a local access network system could be either a point-to-point, active, or passive point-to-multipoint architecture. Figure 1 shows the architectures considered, which range ITU-T Rec. G.983.1(01/2005) 5 fi-om Fibre to the Home (FTTH), thro
39、ugh Fibre to the Building/Curb (FTTB/C) to Fibre to the Cabinet (FTTCab). The Optical Access Network (OAN) is common to all architectures shown in Figure 1, hence commonality in this system has the potential to generate large world-wide volumes. Access network CBNU Optical Network Unit OLT Optical L
40、ine Terminatioii NT Network Tennivialion ONT Optical Network Tennimtiort Figure UG.983.1- Network architecture The FTTB/C and FTTCab network options are predominantly different only as a result of implementation; therefore, they can be treated similarly in this Recommendation. 5.1.1 FTTCab/C/B scena
41、rio Within this scenario the following service categories have been considered - Asymmetric broadband services (e.g., digital broadcast services, VoD, Internet, distant learning, telemedicine, etc.). - Symmetric broadband services (e.g., telecommunication services for small business customers, telec
42、onsulting, etc.). - PSTN and ISDN. The access network must be able to provide in a flexible way the narrow- band telephone services with the appropriate timing for the introduction. 5.1.2 FTTH scenario Fibre to the Home (FTTH) service drivers are similar to those of the previous scenarios and are de
43、termined by the following: - - Indoor ONUs can be considered, resulting in more favorable environmental conditions. No change of intermediate ONU is required to upgrade access network capabilities to accommodate future evolution of broadband and multimedia services. Maintenance is easy, because it r
44、equires maintenance only for fibre systems, and all fibre systems are regarded as more reliable than hybrid fibre-metallic ones. - FTTH is a driver for the development of advanced optoelectronics technologies. The greater volume in production of optical modules will also accelerate the reduction in
45、cost. When these factors can be fully exploited they may counterbalance a slightly higher per line cost. In that situation the FTTH scenario may be regarded as economically feasible even in the short term. - 6 ITU-T Rec. G.983.1(01/2005) 5.2 Reference configuration The reference configuration fi-om
46、ITU-T Rec. G.982 is shown in Figure 2. I bj reit-pence point (T,)/(T) reference point I 6.983.4 -FOZ rejerence point pj Optical Network khit 0m-j Optical Disuibution Network AF Adaptation Fiinction s a b) OLT Optical Ehe Termia1ation Point on the optical fibre just afier the (9(,Tjl)nraheamlK9NnUpst
47、reaml optical conndctinn point upstream direction for signals travelling fi-om the ONU(s) to the OLT. 5.2.2 This interface at the reference points S/R and WS is defined as IFPON. This is a PON-specific interface that supports all the protocol elements necessary to allow the transmission between OLT
48、and ONUs. Interface at the reference points S/R and R/S ITU-T Rec. G.983.1(01/2005) 7 5.3 Functional blocks 5.3.1 Optical Line Termination The Optical Line Termination (OLT) interface is over the SNI to service nodes, and to the PON. The OLT is responsible for managing all the PON-specific aspects o
49、f the ATM transport system. The ONU and OLT provide transparent ATM transport service between the UNIS and the SNI over the PON. 5.3.2 Optical Network Unit The Optical Network Unit (ONU) interfaces over the IFPON to the OLT, and to the UNI. Together with the OLT, the ONU is responsible for providing transparent ATM transport service between the UNI and the SNI. In this architecture, the ATM transport protocols at an IFPON are described as consisting of Physical Media Dependent layer, Transmission Convergence layer, and ATM layer. This architecture is only intended to address the tran
