Advantage and Disadvantage of SDH

What is SDH? Why SDH? SDH, also known as Synchronous Digital Hierarchy, is a synchronous transmission technology based on optical fiber communication systems. It is widely used in many fields such as telecommunications, communications, security, and medical care. This article mainly introduces the advantage and disadvantage of SDH technology.

Part I.What is SDH?

What is SDH ?

SDH, also known as Synchronous Digital Hierarchy, is a synchronous transmission technology based on optical fiber communication systems.

SDH is also a transmission network system. It is different from PDH in that it is an information structure. It can provide corresponding levels of information for the transmission of digital signals at different rates.

SDH is a synchronous TDM technology that multiplexes low-order signals into high-order signals.

The multiplexing feature of SDH is reflected in its ability to multiplex 63 channels of 2.048Mbps E1 signals into the 155.52Mbps signal STM-1.

SDH is fully compatible with the existing PDH network. It can also accommodate various new digital service signals.

Part II. What’s the advantage of SDH?

1.Highly Unified Standards

SDH has a globally unified network node interface (NNI) and multiplexing structure.

The unified network node interface specifies the interface rate, interface form, interface signal level characteristics, timing characteristics, and synchronization methods between devices.

This means that no matter which manufacturer produces SDH equipment. As long as they follow this unified interface standard, they can be easily connected together to form a complete communication network.

This feature of SDH enables equipment produced by different manufacturers to connect and interoperate with each other.

This greatly improves the compatibility and flexibility of the network.

2.Strong Network Management Capabilities

Strong Network management capabilities is one of the advantage of sdh.

The SDH frame structure contains a wealth of overhead bits. It provide powerful support for network operation, management, maintenance, and assignment.

Through software downloading, distributed management of each network unit can be achieved. While facilitating the timely development and upgrade of new functions and features.

This distributed management method not only improves the efficiency of network management, but also promotes the development of advanced network management systems and intelligent equipment.

At the same time, the rich overhead bits also allow network operators to monitor network status in real time, discover and solve problems in a timely manner, thereby improving network reliability and stability.

3.Flexible Multiplexing and Demultiplexing

The Flexible Reuse and De-reusability is also one of the advantage of sdh.

(1)SDH adopts synchronous multiplexing and flexible mapping structure. Therefore digital signals of different rates can be easily multiplexed into high-speed signals and demultiplexed from high-speed signals at the same time.

Specifically, SDH’s multiplexing and demultiplexing functions are realized through its specific frame structure and multiplexing mapping structure.

In terms of multiplexing, SDH uses synchronous multiplexing. It can map low-speed signals to high-speed signals to achieve multiplexing of multiple low-speed signals.

This multiplexing method not only improves transmission efficiency, but also simplifies the network structure and reduces network costs.

(2)In addition, SDH supports a variety of mapping and multiplexing structures and can be flexibly configured according to business needs. It enables the SDH network to adapt to different application scenarios and changing needs.

In terms of demultiplexing, SDH also shows its flexibility.

(3)The signals transmitted through the SDH network can be demultiplexed at the receiving end to separate the low-speed signals from the high-speed signals.

This demultiplexing process is achieved by positioning the position of the low-speed signal in the frame through a pointer. Therefore the receiving end can directly extract the required low-speed signal.

Flexible multiplexing and demultiplexing enable SDH fiber optic networks to support multiple services. Including voice, data, images, etc. Thereby achieving efficient and reliable data transmission.

Advantage of SDH Multiplexing and Demultiplexing

Advantage of SDH Multiplexing and Demultiplexing

4.Efficient Transmission Performance

SDH occupies an important position in modern communication networks due to its efficient transmission performance. Among them, time division multiplexing technology is the key to its efficient transmission.

Time division multiplexing allows SDH to divide multiple signals into several time slots in time. Then it arranges them in a certain order to form a high-speed digital signal stream.

In this way, multiple signals can be transmitted alternately on the same physical channel.

This technology makes full use of the limited transmission bandwidth. It allowing the SDH network to support more signal transmissions, thus greatly improving transmission efficiency.

Advantage of SDH efficient-Transmission

5.Support Network interconnection

The SDH fiber optic networks can quickly and dynamically adjust service configurations according to different business needs and network conditions.

Such characteristics enable SDH to optimize the use of network resources, thereby achieving efficient network interconnection.

For example, when the traffic on a certain link is too heavy, SDH can transfer some services to other links. Through service scheduling to balance the network load and ensure smooth transmission of services.

Advantage of SDH Internet-Connection

Advantage of SDH Internet-Connection

6.Fiber Optic Bandwidth Can Continue to Increase

SDH fiber optic bandwidth has ever-increasing capabilities. This is reflected in the fact that SDH adopts advanced coding technology, modulation technology and multiplexing technology.

SDH systems are capable of achieving higher data transmission rates on the same physical medium.

Specifically, SDH allows multiple optical signals to be transmitted in parallel on the same optical fiber. This greatly improving the bandwidth utilization of the optical fiber.

7.Powerful Self-healing Ability

SDH (Synchronous Digital Hierarchy) has strong self-healing capabilities. It is one of the most advantage of sdh.

(1)Self-healing capability means that when a network failure or interruption occurs, the SDH system can automatically detect and resume transmission. Thereby ensuring data continuity and reliability.

This self-healing capability is critical to ensuring the stability and availability of network services.

Specifically, SDH’s self-healing function is achieved through its built-in redundant paths and backup equipment.

When the network is operating normally, these redundant paths and backup devices are on standby.

Once the main path fails, the SDH systems can quickly switch to the backup path to achieve automatic recovery from the failure.

This switching process is transparent to users, and they hardly feel that the network has failed.

Advantage of SDH Self Healing Ability

Advantage of SDH Self Healing Ability

(2)In addition, SDH’s self-healing ability is also reflected in its fault detection and recovery mechanism.

Transmission equipment in the SDH fiber optic networks will constantly monitor signal quality, such as optical power, bit error rate and other indicators. Once an abnormality is detected, these devices will immediately trigger the fault detection mechanism and start the automatic recovery process.

This real-time monitoring and rapid recovery capability allows the SDH network to maintain high reliability and stability in the face of various failures.

(3)Finally, SDH also demonstrates its powerful self-healing capabilities in terms of networking methods. SDH supports chain and ring networking modes.

These different topologies give SDH networks great flexibility in design and deployment. The appropriate topology can be selected according to actual needs and network environment.

Especially the ring topology. In the ring topology, the SDH network connects each node through the ring, using the add-drop capability and intelligence of the ADM (add-drop multiplexer) to form a closed-loop transmission path and realize the self-healing function of the network.

When a node or link in the network fails, the SDH network can automatically detect the failure. At the same time, it re-establish communication connections through other paths in the ring structure to ensure continuous transmission of services.

This self-healing mechanism can quickly respond to faults, reduce the impact of faults on services. It can also improve the reliability and stability of the network.

8.Strong Scalability

The Strong scalability is one of the advantage of sdh.

The scalability of SDH is reflected in its support for modular design.

(1)First, the modular design makes the hardware structure of SDH equipment more flexible and configurable.

SDH systems usually consist of multiple functional modules. Such as multiplexers, add-drop multiplexers, regenerative repeaters, etc.

Each module has specific functionality and can work independently or in conjunction with other modules. By adding or reducing the number of modules, the system’s capacity can be easily scaled up or down to meet network needs of different sizes.

(2)Secondly, the modular design makes the SDH system software highly scalable.

Software modules can be developed, tested and upgraded independently without affecting the operation of the entire system.

This enables the SDH system to support new services and functions without requiring large-scale transformation of the entire system.

Through software upgrades, new protocols, algorithms or functional features can be easily added to meet changing business needs.

(3)In addition, the modular design also makes the maintenance and management of the SDH system more convenient.

Each module has an independent fault detection and recovery mechanism. When a module fails, the faulty module can be quickly located. And it can be replaced without affecting the normal operation of the entire system.

This greatly shortens fault recovery time and improves system availability and reliability.

Advantage of SDH Strong Scalability

Advantage of SDH Strong Scalability

9.Wide Application

SDH is widely used in many fields such as telecommunications, communications, security, and medical care.

(1)First of all, SDH is widely used in telecommunications and communication fields.

It can be used to implement various transmission services such as telephone, mobile communications, broadband networks, satellite communications, and digital television.

As the core transmission equipment of telecommunications networks, SDH supports high-speed data transmission and multimedia applications. It can meet the needs of different services.

(2)Secondly, the SDH platform also has important applications in the security field.

It can be used for network monitoring, accurately encrypting and decrypting collected information. It can also be used for ensuring the security, integrity and confidentiality of information, and preventing data from being stolen.

This makes the SDH platform play an important role in protecting critical information and data security.

(3)In addition, the SDH platform is increasingly used in the medical field.

It can be used in computer networks, medical image transmission and other fields in the medical field to realize remote medical diagnosis, medical image transmission, medical data interoperability and other services.

Through the SDH platform, medical institutions can achieve efficient and accurate data transmission and sharing. It can improving the quality and efficiency of medical services.

10.Strong Compatibility

The strong compatibility of SDH is reflected in its multi-service compatibility, international compatibility and standardization of network interfaces.

(1)Multi-service compatibility is reflected in the fact that SDH is not only fully compatible with the existing PDH network, but can also accommodate various new service signals.

For example, the optical fiber distributed data interface signal FDDI, the distributed queuing dual bus signal DQDB of the metropolitan area network, the asynchronous transfer mode ATM and Ethernet data in the broadband ISDN, etc.

This forward and backward compatibility makes SDH a common transmission platform.

(2)International compatibility is reflected in the fact that SDH is the equivalent standard of SONET on an international scale, aiming to promote the interoperability of global communication equipment.

This means that no matter which country you are in, as long as you follow the SDH standard, communication equipment can achieve seamless connection and interoperability, thus greatly simplifying the construction and maintenance of transnational networks.

(3)The standardization of network interfaces is reflected in SDH’s unified specification of network node interfaces (NNI).

This includes digital signal rate levels, frame structures, multiplexing methods, line interfaces, and monitoring and management.

This standardization makes it easy to interconnect equipment from different manufacturers, making it possible to install equipment from different manufacturers on the same transmission line, reflecting its horizontal compatibility.

Strong compatibility enables SDH to adapt to various complex network environments and meet different business needs, becoming an important part of modern communication networks.

Part III. What’s the disadvantage of SDH?

Although SDH also has some disadvantages, the disadvantage of SDH cannot cover up the advantages of SDH.

1.Complex Implementation

The Complex Implement tation is the most biggest disadvantage of sdh.</p>

The implementation of SDH is complex  in many aspects.

(1)First, SDH uses a pointer adjustment mechanism, which increases the complexity of the device.

(2)Secondly, the extensive use of software technology in the SDH system improves the flexibility and functionality of the system, but also increases the difficulty of implementation.

(3)Finally, the implementation of SDH also needs to consider compatibility with other communication systems.

2.Complex Management

The Complex Management is also the disadvantage of sdh.</p>

The management complexity of SDH is also reflected in many aspects.

(1)First of all, SDH fiber optic networks management involves a large number of devices, interfaces and protocols. This requires unified configuration, monitoring and maintenance.

(2)Secondly, SDH’s network management authority is relatively large. Once an error occurs in the network management, the entire network may be paralyzed.

(3)In addition, software technology is widely used in SDH networks. So software failures, operational errors and other problems may have a significant impact on network management.

3.High Installation Cost

The high installation cost of SDH is reflected in many aspects.It’s also a disadvantage of SDH.</p>

(1)First of all, the hardware equipment cost of SDH system is relatively high. However, with the continuous development of communication technology, the design and manufacturing process of SDH equipment are also continuously improved. This makes the manufacturing and implementation costs of equipment continue to decrease.

The prices of some of Baudcom’s previous SDH products have dropped a lot in the past two years due to improvements in communication technology.

(2)Secondly, the construction of SDH fiber optic networks require large-scale infrastructure investment.

(3)In addition, the installation and debugging of the SDH systems also requires professional technical personnel. This adds a certain amount of labor costs.

4.Low Bandwidth Utilization

The low bandwidth utilization is a disadvantage of sdh. The low bandwidth utilization of SDH is mainly reflected in the large number of overhead bytes added to SDH.

This results in a corresponding reduction in the number of bytes needed to deliver valid information at the same capacity.


Post time:2024-05-01

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