OTN学习笔记1-5 完整版
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OTN学习笔记543、An overview of OTS, OMS and OCh overhead is presented in Figure 15-1. An overview of OTUk, ODUk and OPUk overhead is presented in Figures 15-2 and 15-3.OTS、OMS和OCh开销示于图15-1。
OTUk、ODUk和OPUk示于图15-2和15-3。
44、OPUk OH information is added to the OPUk information payload to create an OPUk. It includes information to support the adaptation of client signals. The OPUk OH is terminated where the OPUk is assembled and disassembled.The OPUk overhead consists of: payload structure identifier (PSI) including the payload type (PT), overhead associated with concatenation and overhead (e.g., justification control and opportunity bits) associated with the mapping of client signals into the OPUk payload. The OPUk PSI and PT overhead locations are shown in Figure 15-23.One byte is allocated in the OPUk overhead to transport a 256-byte payload structure identifier (PSI) signal. The byte is located in row 4, column 15 of the OPUk overhead. A one-byte payload type signal is defined in the PSI[0] byte of the payload structure identifier to indicate the composition of the OPUk signal. Seven bytes are reserved in the OPUk overhead for mapping and concatenation specific overhead.OPUk mapping specific overhead are located in rows 1 to 3, columns 15 and 16 and column 16 row 4. In addition, 255 bytes in the PSI are reserved for mapping and concatenation specificpurposes.The use of these bytes depends on the specific client signal mapping.将OPUk OH信息加入到OPUk信息净荷上以创建一个OPUk。
OTN学习笔记OTN基本原理OTN产生背景原有WDM技术仅在物理层面上统一标准,即针对WDM系统中传送信号的波段、频率间隔等做出了规定,对信号的帧结构没有制定统一的标准。
使得WDM在传递如STM64、10GbE等信号时产生了性能监测、帧结构、开销管理等难题。
OTN特点OTN是以波分复用技术为基础,通过G.872、G.709、G.798等一系列ITU-T的建议所规范的新一代“数字传送体系”和“光传送体系”。
OTN解决传统WDM网络无波长/子波长业务调度能力、组网能力弱、保护能力弱等问题。
在OTN网络的边缘层,业务信号被封装进入统一的、开销丰富的OTN体制中的帧结构中去,实现基于OTN体制的WDM全网统一运营、管理、维护。
OTN在电域为OTH,在光域为ROADM。
OTN在光域内可以实现业务信号的传递、复用、路由选择、监控,并保证其性能要求和生存性。
OTN可以支持多种上层业务或协议,如SONET/SDH,ATM,Ethernet,IP,PDH,FibreChannel,GFP,MPLS,OTN虚级联, ODU复用等。
下表为ITU-T构建的OTN协议框架。
OTN基本概念光通路opticalchannel(OCh[r]),OCh是用于支持OCh路径的信息结构,根据是否支持非随路开销(OCh_OH),定义了两种OCh,即支持非随路开销的全功能光通路(OCh)和不支持非随路开销的简化功能光通路(OChr)。
本标准定义的OCh的客户信号为OTUk信号,其它数字客户信号如STM-N、以太网等OTM也可支持。
另外,OCh应具有区分两个不同的OCh信号(一个信号承载OTU1,另一个信号承载OTU2或GbE)的特征,具体实现待研究。
光通路数据单元opticalchanneldataunit(ODUk),ODUk是包括信息净荷(OPUk)和与ODUk开销相关的信息结构。
ODUk的容量由k区分,k=0,1,2,2e,3,4。
OTN学习笔记323、optical transport hierarchy (OTH): The OTH is a hierarchical set of digital transport structures, standardized for the transport of suitably adapted payloads over optical transmission networks.光传送序列(OTH):OTH是一种数字传送结构的序列组,用于规范光传输网络上稳定适配净荷的传送。
24、OTH multiplexing: A procedure by which optical channels are multiplexed.OTH复用:一种光信道复用的过程。
25、non-associated overhead (naOH): Supervisory information transported in an OOS非联合开销(naOH):在OOS中传送的监控信息。
26、CBR2G5: A constant bit-rate signal of 2 488 320 kbit/s ± 20 ppm. An example of such signal is a STM-16 signal. CBR10G: A constant bit-rate signal of 9 953 280 kbit/s ± 20 ppm. An example of such signal is a STM-64 signal. CBR40G: A constant bit-rate signal of 39 813 120 kbit/s ± 20 ppm. An example of such signal is a STM-256 signalCBR2G5:一种2488320kbit/s±20ppm固定比特率信号。
OTN学习笔记
BIP8(奇偶校验)
层层误码检测;但OTN不是,OTN中的BIP误码检测有SM-BIP、
PM_BIP、TCM,三种开销的校验区域都是ODUk中的OPUk区域,每个ODUk BIP-8对第i帧ODUk中的OPUk区域的比特做奇偶校验,将计算的结果放到第i+2帧中的SM、PM、TCM BIP-8的相应开销中;
对于FEC是这样的:当ODUk加上OTUk的开销后的所有字节进行FEC计算,计算结果放到FEC区域中;最后将带有FEC的整个OTUk进行扰码;收端进行反向操作,先解扰码,再进行FEC纠错,纠错后再提取SM段开销,然后是PM段开销、TCM开销,所以可以很清楚的看到:
如果收端有误码,首先进行的是FEC纠错,这时有两种情况:1、FEC纠错后无误码,则SM、PM、TCM均不会上报BIP误码;2、FEC纠错后有误码,则SM、PM、TCM可能会上报BIP误码,这时候要注意,如果该点不是业务落地点,只是中继站,则只会有SM段BIP上报,因为此时不检测ODUk的开销;如果此时是业务落地点,则会有SM、PM、TCM的BIP上报,但可能会因为告警抑制关系,不一定会同时上报而已。
PM和TCM并不属于同一级别
一般来说PM段终结有两种情况:
1.高阶ODU解复用成低阶ODU颗粒
2.line侧ODU解出client信号
这说明当PM段终结以后,TCM就不复存在
但是反之,TCM段终结以后,PM段还是存在的,这和G.709没关系主要看G.798,无论TT点还是adaption点,TCM和PM都不在一个function里处理。
OTN学习笔记1、The optical transport hierarchy (OTH) supports the operation and management aspects of optical networks of various architectures, e.g., point-to-point, ring and mesh architectures.This Recommendation defines the interfaces of the optical transport network to be used within and between subnetworks of the optical network, in terms of:–optical transport hierarchy (OTH);–functionality of the overhead in support of multi-wavelength optical networks;–frame structures;–bit rates;–formats for mapping client signals.光传送序列(OTH)支持各种体系结构(即点对点、环形和网孔形体系结构)光网络的运行和管理。
依据光传送序列(OTH)、多波长光网络支持中的开销功能、帧结构比特率及映射客户信号的方式,本建议定义了光传送网络的接口,以便将这些接口用于光网络的子网内部和子网之间。
2、optical transport module (OTM-n.m): The OTM is the information structure that is transported across an ONNI. The index n and m define the number of supported wavelengths and bit rates at the interface. Two OTM structures are defined:The OTM with full functionality (OTM-n.m) is the information structure used to support optical transmission section (OTS) layer connections in the OTN. The characteristic information of the optical transmission section layer (OTS_CI) consists of information payload (OTS_CI_PLD) and optical transmission section overhead information fields (OTS_CI_OH). The optical transmission section overhead (OTS_OH) information fields are contained within the OTM overhead signal (OOS) information structure. The OTM-n.m consists of up to n multiplexed optical channels and an OTM overhead signal to support the non-associated overhead.The OTM with reduced functionality (OTM-nr.m/OTM-0) is the information structure used to support optical physical section (OPS) layer connections in the OTN. The characteristic information of the optical physical section layer (OPS_CI) consists of information payload (OPS_CI_PLD). OTM-0 consists of a single optical channel without a specific colour assigned. The OTM-nr.m consists of up to n multiplexed optical channels. Non-associated overhead is not supported光传送模块(OTM):OTM是穿越ONNI传送的信息结构。
n和m定义了接口支持的波长数量和比特率。
定义了两种OTM:完全功能OTM(OTM-n.m)和简化功能OTM(OTM-0和OTM-nr.m)。
完全功能OTM(OTM-n.m)是用于支持OTN中光传输段(OTS)层连接的信息结构。
光传输段层的特征信息(OTS_CI)由信息净荷(OTS_CI_PLD)和光传输段开销信息(OTS_CI_OH)组成。
光传输段开销(OTS_OH)信息包含在OTM开销信号(OOS)信息结构中。
为了支持非联合开销,完全功能OTM-n.m由最多n个复用的光信道和一个OTM 开销构成。
简化功能OTM(OTM-nr.m/OTM-0)是用于支持OTN中光物理段(OPS)层连接的信息结构。
光物理段层的特征信息(OPS_CI)由信息净荷(OPS_CI_PLD)组成。
OTM-0由不具有分配特定颜色的单个光信道构成。
OTM-nr.m最多由n个复用光信道组成。
不支持非联合开销。
3、optical channel (OCh[r]): The OCh is the information structure used to support the OChtrail. Two OCh structures are defined.The OCh client signals defined in this Recommendation are the OTUk signals. Other digital client signals (e.g., STM-n, GbE) may be supported by the OTM.Optical channel with full functionality (OCh): The OCh is an information structure consisting of the information payload (OCh_PLD) with a certain bandwidth and non-associated overhead (OCh_OH) for management of the optical channel.Optical channel with reduced functionality (OChr): The OChr is an information structure consisting of the information payload (OCh_PLD) with a certain bandwidth. Non-associated overhead is not supported.光信道(OCh):OCh是用于支持OCh踪迹的信号结构。
定义了两种结构的OCh。
本建议中定义的OCh客户信号为OTUk信号。
可以通过OTM支持其他数字客户信号(即STM-n和GbE)。
完全功能光信道(OCh):为了管理光信道,OCh是一种由具有特定带宽和非联合开销(OCh_OH)的、信息净荷(OCh_PLD)组成的信息结构。
简化功能光信道(OChr):OChr是一种由具有特定带宽的、信息净荷组成的信息结构。
不支持非联合开销。
4、optical channel transport unit (OTUk[V]): The OTUk is the information structure used for transport of an ODUk over one or more optical channel connections. It consists of the optical channel data unit and OTUk related overhead (FEC and overhead for management of an optical channel connection). It is characterized by its frame structure, bit rate, and bandwidth. Two versions of the OTUk are defined:Completely standardized OTUk (OTUk): The completely standardized OTUk is used on OTM IrDIs and may be used on OTM IaDIs. Functionally standardized OTUk (OTUkV): The partly standardized OTUk is used on OTM IaDIs.光信道传送单元(OTUk):OTUk是为了在一个或多个光信道连接上进行光信道数据单元(ODUk)传送的信息结构。
它由ODUk和OTUk相关开销(用于光信道连接的FEC和开销)组成。
它由其帧结构、比特率及带宽规范。
定义了两种版本的OTUk。
完全标准化OTUk(OTUk):完全标准化OTUk可以用于OTM IrDIs和OTM IaDIs。
功能标准化OTUk(OTUkV):部分标准化OTUk用于OTM IaDIs。
5、optical channel payload unit (OPUk): The OPUk is the information structure used to adapt client information for transport over an optical channel. It comprises client information together with any overhead needed to perform rate adaptation between the client signal rate and the OPUk payload rate and other OPUk overhead supporting the client signal transport. This overhead is adaptation specific.光信道净荷单元(OPUk):OPUk是为了用于在一个光信道中传送适配客户信息的信息结构。