光通信——APON/EPON/GPON/10G PON

目录

APON 

EPON 

GPON 

上下行对称和非对称速率

OAM功能

汇聚子层

ATM封装方式

GEM封装方式

10G EPON

EPON/GPON技术原理和特点 

工作原理 

关键技术

(1)测距、同步 

(2)突发发送和接收

(3) 用户安全

(4)动态带宽调整(DBA) 

技术优势 

EPON与GPON技术比较

EPON技术特点  

GPON技术特点  


APON,基于ATM的无源光接入技术,遵循ITU-T C.983系列标准。
EPON,基于以太网的无源光接入技术,遵循IEEE 802.3ah系列标准。
GPON,基于ATM/GEM的无源光接入技术,遵循ITU-T G.984系列标准。

 从20世纪90年代开始,PON技术经历了不成功的窄带PON和基于ATM的无源光网络(APON/BPON,ITU-T G.983)。现在应用比较广泛的主要包括以太网无源光网络(EPON,IEEE802.3ah)、具有Gbit/s传送能力的无源光网络(GPON,ITU-T G.984)以及10Gbit/s速率的PON技术。

APON 

APON是一种宽带传输能力的解决措施,它具备ATM的多个Byte Rate及多种数据形态和业务的支撑能力,当然还有无源光纤网络的优越特性。打下了坚实而优良的基础,从而使得多路连接形式和单点对多个点的传输模式的实现成为了可能。这样的通信传输构造使得全部带宽分享给多个不同的用户变为了现实。 

APON的数据传输的特点是长度是固定不变的。有两种差别较大的速度频率构造:分为不对称和对称两种,不对称的结构是上行155.52Mbitls,下行622.08Mbit/s;对称的构造是:上行和下行均为155.52Mb/s。从远期发展形式来看,ATM化的宽带/无源光纤网络的可以使用的带宽存在巨大的不足:下行速率虽然可以达到622 Mbitls,但是由于采用分配话路方式,最终分配到各个用户的带宽将会极大的降低。这种方式造成不能适应用户的不断增长的需求,不能大面积推广。

EPON 

EPON支持上下行对称1.25Gbit/s速率,支持10km和20km两种最大传输距离,支持的用户分支数普遍为32

 EPON系统具有技术简单、成本低、速率高、可扩展性强,对数据业务的适配效率高等优点,能够以较低成本高效率地传送IP业务。目前在国内得到了以中国电信为代表的运营商的规模应用,并且呈现出规模逐年递增的发展态势。

GPON 

上下行对称和非对称速率

  • 对称速率:上行(从用户到网络)和下行(从网络到用户)速率相同。这种配置适用于需要均衡上传和下载速度的应用。

  • 非对称速率:上行和下行速率不同,通常下行速率更高。这种配置适合于大多数互联网使用场景,因为下载需求通常大于上传需求。

GPON采用了125μs的帧长及定时机制,能够比较容易地支持TDM业务和话音业务。GPON可以支持622Mbit/s、1.25Gbit/s和2.5Gbit/s上下行对称速率或非对称速率,支持10km和20km两种最大传输距离,支持的用户分支数可达64甚至128
GPON除了支持更高的速率和更大的分路比外,综合业务接入环境下的总传输效率高,而且能够很好地承载TDM业务和话音业务,信号传输时延和抖动能够得到保证,而且提供丰富的OAM&P功能和良好的扩展性。 

具有Gbit/s传送能力的无源光网络。GPON技术的目标是形成传输速率更高、能高效承载多种业务(包括实时业务、数据业务等)并具有强大OAM功能和扩展能力的宽带PON技术。GPON标准引入了一个新的传输汇聚(TC)子层,并规定TC子层可以采用ATM和GEM两种封装方式。

GPON技术中,传输汇聚(TC)子层是负责将用户数据转化为适合光纤传输的数据格式的一层。它起着数据封装、复用和解复用的作用,使

1 Scope 11 2 References 11 3 Terms and definitions 12 4 Abbreviations 14 5 Conventions 17 6 Optical transport network interface structure 18 6.1 Basic signal structure 19 6.1.1 OCh substructure 19 6.1.2 Full functionality OTM n.m (n ≥ 1) structure 19 6.1.3 Reduced functionality OTM nr.m and OTM 0.m structure 20 6.2 Information structure for the OTN interfaces 20 7 Multiplexing/mapping principles and bit rates 24 7.1 Mapping 26 7.2 Wavelength division multiplex 27 7.3 Bit rates and capacity 27 7.4 ODUk Time Division Multiplex 28 8 Optical transport module (OTM n.m, OTM nr.m, OTM 0.m) 30 8.1 OTM with reduced functionality (OTM 0.m, OTM nr.m, OTM-0v.m) 30 8.1.1 OTM 0.m 31 8.1.2 OTM nr.m 31 8.1.2.1 OTM 16r.m 31 8.1.2.2 OTM 32r.m 33 8.1.3 OTM 0v.m Error! Bookmark not defined. 8.2 OTM with full functionality (OTM n.m) 35 9 Physical specification of the ONNI 37 9.1 OTM 0.m 37 9.2 OTM nr.m 37 9.2.1 OTM 16r.m 37 9.2.2 OTM 32r.m 37 9.3 OTM n.m 37 9.3 OTM 0v.m Error! Bookmark not defined. 10 Optical channel (OCh) 37 10.1 OCh with full functionality (OCh) 37 10.2 OCh with reduced functionality (OChr) 38 11 Optical channel transport unit (OTU) 38 11.1 OTUk frame structure 38 11.2 Scrambling 40 12 Optical channel data unit (ODUk) 40 12.1 ODUk frame structure 40 13 Optical channel payload unit (OPUk) 41 14 OTM overhead signal (OOS) 41 15 Overhead description 41 15.1 Types of overhead 43 15.1.1 Optical channel payload unit overhead (OPUk OH) 43 15.1.2 Optical channel data unit overhead (ODUk OH) 43 15.1.3 Optical channel transport unit overhead (OTUk OH) 44 15.1.4 Optical channel non-associated overhead (OCh OH) 44 15.1.5 Optical multiplex section overhead (OMS OH) 44 15.1.6 Optical transmission section overhead (OTS OH) 44 15.1.7 General management communications overhead (COMMS OH) 44 15.2 Trail trace identifier and access point identifier definition 44 15.3 OTS OH description 46 15.3.1 OTS trail trace identifier (TTI) 46 15.3.2 OTS backward defect indication – Payload (BDI-P) 46 15.3.3 OTS backward defect indication – Overhead (BDI-O) 46 15.3.4 OTS payload missing indication (PMI) 46 15.4 OMS OH description 47 15.4.1 OMS forward defect indication – Payload (FDI-P) 47 15.4.2 OMS forward defect indication – Overhead (FDI-O) 47 15.4.3 OMS backward defect indication – Payload (BDI-P) 47 15.4.4 OMS backward defect indication – Overhead (BDI-O) 47 15.4.5 OMS payload missing indication (PMI) 47 15.5 OCh OH description 47 15.5.1 OCh forward defect indication – Payload (FDI-P) 47 15.5.2 OCh forward defect indication – Overhead (FDI-O) 47 15.5.3 OCh open connection indication (OCI) 47 15.6 OTUk/ODUk frame alignment OH description 48 15.6.1 OTUk/ODUk frame alignment overhead location 48 15.6.2 OTUk/ODUk frame alignment overhead definition 48 15.6.2.1 Frame alignment signal (FAS) 48 15.6.2.2 Multiframe alignment signal (MFAS) 48 15.7 OTUk OH description 49 15.7.1 OTUk overhead location 49 15.7.2 OTUk overhead definition 50 15.7.2.1 OTUk section monitoring (SM) overhead 50 15.7.2.1.1 OTUk SM trail trace identifier (TTI) 50 15.7.2.1.2 OTUk SM error detection code (BIP-8) 50 15.7.2.1.3 OTUk SM backward defect indication (BDI) 51 15.7.2.1.4 OTUk SM backward error indication and backward incoming alignment error (BEI/BIAE) 51 15.7.2.1.5 OTUk SM incoming alignment error overhead (IAE) 52 15.7.2.1.6 OTUk SM reserved overhead (RES) 52 15.7.2.2 OTUk general communication channel 0 (GCC0) 52 15.7.2.3 OTUk reserved overhead (RES) 52 15.7.3 OTUkV overhead 52 15.8 ODUk OH description 53 15.8.1 ODUk OH location 53 15.8.2 ODUk OH definition 54 15.8.2.1 ODUk path monitoring (PM) overhead 54 15.8.2.1.1 ODUk PM trail trace identifier (TTI) 54 15.8.2.1.2 ODUk PM error detection code (BIP-8) 54 15.8.2.1.3 ODUk PM backward defect indication (BDI) 55 15.8.2.1.4 ODUk PM backward error indication (BEI) 55 15.8.2.1.5 ODUk PM status (STAT) 56 15.8.2.2 ODUk tandem connection monitoring (TCM) overhead 56 15.8.2.2.1 ODUk TCM trail trace identifier (TTI) 58 15.8.2.2.2 ODUk TCM error detection code (BIP-8) 59 15.8.2.2.3 ODUk TCM backward defect indication (BDI) 59 15.8.2.2.4 ODUk TCM backward error indication (BEI) and backward incoming alignment error (BIAE) 59 15.8.2.2.5 ODUk TCM status (STAT) 60 15.8.2.2.6 TCM overhead field assignment 61 15.8.2.2.7 ODUk tandem connection monitoring activation/deactivation coordination protocol 62 15.8.2.3 ODUk general communication channels (GCC1, GCC2) 62 15.8.2.4 ODUk automatic protection switching and protection communication channel (APS/PCC) 62 15.8.2.5 ODUk fault type and fault location reporting communication channel (FTFL) 63 15.8.2.5.1 Forward/backward fault type indication field 63 15.8.2.5.2 Forward/backward operator identifier field 64 15.8.2.5.3 Forward/backward operator specific field 65 15.8.2.6 ODUk experimental overhead (EXP) 65 15.8.2.7 ODUk reserved overhead (RES) 65 15.9 OPUk OH description 65 15.9.1 OPUk OH location 65 15.9.2 OPUk OH definition 66 15.9.2.1 OPUk payload structure identifier (PSI) 66 15.9.2.1.1 OPUk payload type (PT) 66 15.9.2.2 OPUk mapping specific overhead 67 16 Maintenance signals 67 16.1 OTS maintenance signals 68 16.1.1 OTS payload missing indication (OTS-PMI) 68 16.2 OMS maintenance signals 68 16.2.1 OMS forward defect indication – Payload (OMS-FDI-P) 68 16.2.2 OMS forward defect indication – Overhead (OMS-FDI-O) 68 16.2.3 OMS payload missing indication (OMS-PMI) 68 16.3 OCh maintenance signals 68 16.3.1 OCh forward defect indication – Payload (OCh-FDI-P) 68 16.3.2 OCh forward defect indication – Overhead (OCh-FDI-O) 68 16.3.3 OCh open connection indication (OCh-OCI) 68 16.4 OTUk maintenance signals 68 16.4.1 OTUk alarm indication signal (OTUk-AIS) 68 16.5 ODUk maintenance signals 69 16.5.1 ODUk alarm indication signal (ODUk-AIS) 69 16.5.2 ODUk open connection indication (ODUk-OCI) 69 16.5.3 ODUk locked (ODUk-LCK) 70 16.6 Client maintenance signal 71 16.6.1 Generic AIS for constant bit rate signals 71 17 Mapping of client signals 72 17.1 Mapping of CBR2G5, CBR10G, CBR10G3 and CBR40G signals (e.g., STM-16/64/256, 10GBASE-R) into OPUk 72 17.1.1 Mapping a CBR2G5 signal (e.g., STM-16) into OPU1 74 17.1.2 Mapping a CBR10G signal (e.g., STM-64) into OPU2 75 17.1.3 Mapping a CBR40G signal (e.g. STM-256) into OPU3 75 17.1.4 Mapping a CBR10G3125 signal (e.g., 10GBASE-xR) into OPU2e 76 17.2 Mapping of ATM cell stream into OPUk 76 17.3 Mapping of GFP frames into OPUk 77 17.4 Mapping of test signal into OPUk 78 17.4.1 Mapping of a NULL client into OPUk 78 17.4.2 Mapping of PRBS test signal into OPUk 78 17.5 Mapping of a non-specific client bit stream into OPUk 79 17.5.1 Mapping bit stream with octet timing into OPUk 80 17.5.2 Mapping bit stream without octet timing into OPUk 80 17.6 Mapping of other constant bit-rate signals with justification into OPUk 80 17.7 Mapping a 1000BASE-X and FC-1200 signal via timing transparent transcoding into OPUk 80 17.7.1 Mapping a 1000BASE-X signal into OPU0 81 17.7.2 Mapping a FC-1200 signal into OPU2e 88 18 Concatenation 88 18.1 Virtual concatenation of OPUk 91 18.1.1 Virtual concatenated OPUk (OPUk-Xv, k = 1 .. 3, X = 1 .. 256) 91 18.1.2 OPUk-Xv OH description 92 18.1.2.1 OPUk-Xv OH location 92 18.1.2.2 OPUk-Xv OH definition 93 18.1.2.2.1 OPUk-Xv Payload Structure Identifier (PSI) 93 18.1.2.2.1.1 OPUk-Xv Payload Type (vcPT) 93 18.1.2.2.1.2 OPUk-Xv Payload Structure Identifier Reserved overhead (RES) 94 18.1.2.2.2 OPUk-Xv Virtual Concatenation Overhead (VCOH1/2/3) 94 18.1.2.2.2.1 OPUk-Xv Virtual Concatenation MultiFrame Indicator (MFI1, MFI2) 94 18.1.2.2.2.2 OPUk-Xv Sequence Indicator (SQ) 95 18.1.2.2.2.3 OPUk-Xv LCAS Control Words (CTRL) 95 18.1.2.2.2.4 OPUk-Xv LCAS Member Status Field (MST) 95 18.1.2.2.2.5 OPUk-Xv LCAS Group Identification (GID) 95 18.1.2.2.2.6 OPUk-Xv LCAS Re-Sequence Acknowledge (RS-Ack) 95 18.1.2.2.2.7 OPUk-Xv LCAS Cyclic Redundancy Check (CRC) 96 18.1.2.2.2.8 OPUk-Xv VCOH Reserved Overhead 96 18.1.2.2.3 OPUk Mapping Specific Overhead 96 18.2 Mapping of client signals 96 18.2.1 Mapping of CBR signals (e.g., STM-64/256) into OPUk-4v 96 18.2.1.1 Mapping a CBR10G signal (e.g. STM-64) into OPU1-4v 97 18.2.1.2 Mapping a CBR40G signal (e.g. STM-256) into OPU2-4v 98 18.2.2 Mapping of CBR signals (e.g., STM-256) into OPUk-16v 98 18.2.2.1 Mapping a CBR40G signal (e.g., STM-256) into OPU1-16v 100 18.2.3 Mapping of ATM cell stream into OPUk-Xv 101 18.2.4 Mapping of GFP frames into OPUk-Xv 102 18.2.5 Mapping of test signal into OPUk-Xv 102 18.2.5.1 Mapping of a NULL client into OPUk-Xv 102 18.2.5.2 Mapping of PRBS test signal into OPUk-Xv 103 18.2.6 Mapping of a non-specific client bit stream into OPUk-Xv 104 18.2.6.1 Mapping bit stream with octet timing into OPUk-Xv 105 18.2.6.2 Mapping bit stream without octet timing into OPUk-Xv 105 18.3 LCAS for virtual concatenation 105 19 Mapping ODUj signals into the ODTUjk and ODTU? signals 105 19.1 OPUk Tributary Slot definition 105 19.1.1 OPU2 Tributary Slot allocation 106 19.1.2 OPU3 Tributary Slot allocation 107 19.1.3 OPU4 Tributary Slot allocation 110 19.1.4 OPU1 Tributary Slot allocation 109 19.2 ODTUjk and ODTU? definitions 110 19.2.1 ODTU12 110 19.2.2 ODTU13 110 19.2.3 ODTU23 110 19.2.7 ODTU01 110 19.2.8 ODTU? Error! Bookmark not defined. 19.3 Multiplexing ODTUjk and ODTU? signals into the OPUk 111 19.3.1 ODTU12 mapping into one OPU2 2.5G Tributary Slot 111 19.3.2 ODTU13 mapping into one OPU3 2.5G Tributary Slot 112 19.3.3 ODTU23 mapping into four OPU3 2.5G Tributary Slots 113 19.3.4 ODTU01 mapping into one OPU1 1.25G Tributary Slot 114 19.4 OPUk Multiplex Overhead 115 19.4.1 OPUk Multiplex Structure Identifier (MSI) 118 19.4.1.1 OPU2 Multiplex Structure Identifier (MSI) 119 19.4.1.2 OPU3 Multiplex Structure Identifier (MSI) 119 19.4.1.3 OPU4 Multiplex Structure Identifier (MSI) 120 19.4.1.4 OPU1 Multiplex Structure Identifier (MSI) Error! Bookmark not defined. 19.4.2 OPUk Payload Structure Identifier Reserved overhead (RES) 120 19.4.3 OPUk Multiplex Justification Overhead (JOH) 121 19.4.3.1 Asynchronous Mapping Procedure Error! Bookmark not defined. 19.4.3.2 Asynchronous Generic Mapping Procedure Error! Bookmark not defined. 19.4.4 OPU4 Multi Frame Identifier overhead (OMFI) 121 19.5 Mapping ODUj into ODTUjk 121 19.5.1 Mapping ODU1 into ODTU12 122 19.5.2 Mapping ODU1 into ODTU13 123 19.5.3 Mapping ODU2 into ODTU23 124 19.5.4 Mapping ODU0 into ODTU01 126 ODU0 into OPUk Tributary Slot Mapping Error! Bookmark not defined. 19.6 Mapping ODUj into ODTU? Error! Bookmark not defined.
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