What are the Rates of Optical Transport Network (OTN)?

Optical Transport Network (OTN) is a type of modern telecommunication technology that provides efficient and reliable data transmission over optical fiber networks. OTN provides a wide range of services including voice, video, data, and storage networking. It is designed to meet the demanding needs of today's networks and can be used to transport data between different types of network elements, such as traditional routers, switches, and servers.

The cost of an OTN can vary depending on the type of service being provided. Some of the factors that can influence the cost of an OTN include the type of fiber being used, the distance of the fiber, the type of equipment being used, and the number of endpoints involved in the network.

Standard OTN services are typically purchased on a per-mile basis and involve the use of higher-grade fiber and more sophisticated equipment. Prices for these services can range from a few thousand dollars for a few miles of fiber to several hundred thousand for larger, more complex networks.

For end users, the cost of an OTN is typically lower than traditional telecommunication services. This is because an OTN can handle a larger volume of traffic and is more efficient in terms of bandwidth utilization. In addition, an OTN can usually be deployed faster than traditional telecommunication services and requires less maintenance.

In addition to the cost of the OTN itself, there are other associated costs that may need to be considered. These costs can include installation fees, maintenance fees, and other associated fees such as taxes. It is important to research the different fees associated with an OTN to ensure that the total cost of the service will be within the budget.

In general, OTN can provide a cost-effective solution for companies that need to transport large amounts of data. The cost of an OTN will depend on the type of service being provided, the distance of the fiber, the type of equipment being used, and the number of endpoints involved in the network. Companies should research their options carefully to find the most cost-effective solution for their specific needs.

**There are two types of ODTU:**

1) ODTU01, ODTU12, ODTU13, ODTU23 are one type (ODTUjk), referring to the tributary units that map the lower level ODUj to the higher level OPUk, using AMP mapping;

2) ODTU2.ts, ODTU3.ts, and ODTU4.ts is another type (ODTUk.ts), which refers to the tributary unit that uses ts high rate level OPUk, using GMP mapping.

In order to illustrate the rate law of ODTU more clearly, let’s first look at the process of mapping low-rate-level ODUs to high-rate-level OPUs.

Step 1: ODUj can be mapped to ODTUjk by AMP mapping or to ODTUk.ts by GMP mapping.

Step 2: HO OPUk will be divided into many 1.25G/2.5G tributary slots, and ODTUjk or ODTUk.ts will be mapped into these 1.25G/2.5G tributary slots by byte synchronous mapping (simple time division multiplexing).

For example, mapping ODU2 into OPU3 is divided into two steps:

1) first map ODU2 to ODTU23, then map ODTU23 to OPU3

2) The rate of ODTU23 is about 10G, which needs to occupy 8 1.25G tributary slots, so you need to map ODTU23 to the 8 1.25G tributary slots of OPU3.

Another example is to map ODU2 to OPU4, which is divided into 2 steps:

1) first map ODU2 to ODTU4.8

2) The rate of ODTU4.8 is about 10G, which needs to occupy 8 1.25G tributary slots, so you need to map ODTU4.8 to the 8 1.25G tributary slots of OPU4.

It should be noted that the 1.25G tributaries of OPU2/OPU3/OPU4, although they are all called 1.25G tributaries, actually have different rates, with OPU2’s 1.25G tributary being the slowest at about 1.249Gbps and OPU4’s 1.25G tributary being the fastest at about 1.301Gbps.

Rule 5: The payload bandwidth formula of ODTUjk includes two parts: the integer and the mantissa.

1) Integer: OPUk can carry several ODTUjk, then the integer part is 3808 divided by it.

a) OPU1 can carry 2 ODTU01, the integer part 1904=3808/2

b) OPU2 can carry 4 ODTU12, the integer part 952=3808/4

c) OPU3 can carry 16 ODTU23, the integer part 238=3808/16

d) OPU3 can carry 4 ODTU13, the integer part 952=3808/4

2) Mantissa: OPUk can carry several ODTUjk, then the integer part is 1/4 divided by it.

a) OPU1 can carry 2 ODTU01, the fractional part 1/4/2 = 1/8

b) OPU2 can carry 4 ODTU12, the fractional part1/4/4 = 1/16

c) OPU3 can carry 16 ODTU13, the fractional part 1/4/16 = 1/64

d) OPU3 can carry 4 ODTU23, the fractional part 1/4/4 = 4/64

The mapping of ODTU to OPU is time division multiplexing, OPU is divided into multiple 1.25G/2.5G tributary slots (TS) and ODTU is mapped into these tributary slots, the mapping method is simple time division multiplexing.

When OPU1 carries 2 ODTU01, the load of each ODTU01 occupies 1/2 of the OPU1 load, so the load of ODTU01 should be half of the OPU1 load rate, i.e. 3808/2/3808*OPU1 load rate = 1904/3824*ODU1 load rate.

In addition, we need to take into account the NJO adjustment opportunity in the OPU1 overhead. Each OPU1 frame (4 lines) has only 1 byte of NJO adjustment opportunity, so for 2 ODTU01s, each ODTU01 needs two OPU1 frames to have 1 byte of NJO adjustment opportunity. After taking this adjustment opportunity into account, ODTU01 should also add 1/4/2 /3808* OPU1 load rate. This is the fractional part of the bandwidth calculation. It is a similar calculation for both OPU2/OPU3.

Rule 6: The payload rate of ODTUk.ts is proportional to the number of occupied tributary slots ts and proportional to the number of columns of 1.25G tributary slots in OPUk.

ODTUk.ts all use 1.25G tributary slots. ts indicates the number of occupied tributary slots, so the speed is of course proportional to ts. The more ts tributaries are needed, the higher the speed of ODTUk.ts. In different OPUk, the number of columns occupied by 1.25G tributary slots is different. the higher the speed level of OPUk, the less the number of columns occupied by 1.25G tributary slots. Therefore, the rate of ODUk.ts is proportional to the number of 1.25G tributary slots in OPUk when the rate of ODUk is used as the base.

In OPU2, there are 8 1.25G tributary slots, so the number of columns is 3808/8 = 476;

In OPU3, there are 32 1.25G tributary slots, so the number of columns is 3808/32= 119;

In OPU4, there are 80 1.25G tributary slots, so the number of columns is 3800/80 = 47.5 (where the rightmost 8 columns are filled);

ODTUk.ts does not use NJO adjustment opportunities, so its rate is not related to NJO and does not have a fractional part like ODTUjk.

When the data is mapped to OPU (including the case that the customer side signal is directly mapped to OPU, and the low rate level ODU is mapped to the high rate level OPU, etc.), there is a certain difference between the data rate and the OPU load rate.

This difference may be due to the mismatch between the data rate and the OPU rate itself, or it may be caused by the inconsistency between the clock of data generation and the clock of OPU. The rate difference problem can be solved by a reasonable mapping method, and the OTN protocol specifies AMP, BMP, GMP, and GFP-F mapping methods.

AMP: Asynchronous Mapping Procedure

BMP: Bit-synchronous Mapping Procedure

GMP: Generic Mapping Procedure

GFP-F: Frame-mapped Generic Framing Procedure

What are the scalability options for a C
Product News

What is a CPE (Customer Premises Equipme
Product News

What is the use of OLT in GPON?
Product News