Advantages of SDH | disadvantages of SDH

This page covers advantages and disadvantages of SDH. It mentions SDH advantages or benefits and SDH disadvantages or drawbacks. It also describes SDH basics.

What is SDH?

Introduction:
• SDH is the short form of Synchronous Digital Hierarchy.
• This term is used in digital multiplexers installed in telephone exchanges.
• It is European standard similar to SONET which is an American standard.
• It supports different topologies viz. point-point, star, ring etc.
• It multiplexes inputs having same bit rate and derived from common clock source. Hence the name "synchronous".
• Word interleaving is used to combine signals.

Refer PDH versus SDH >>.

Benefits or advantages of SDH

Following are the benefits or advantages of SDH:
➨ A more simplified multiplexing and demultiplexing technique.
➨ Synchronous networking and SDH supports multipoint networking.
➨ Capability of transporting existing PDH signals.
➨ Easy growth to higher bit rates which enhances the administration and maintenance process.
➨ It is capable of transporting broadband signals.
➨ It is multivendor and supports different operators.
➨ It provides network transport services on LAN such as video conferencing, and interactive multimedia.
➨ Optical fibre bandwidth can be increased without limit in SDH.
➨ Switching protection to traffic is offered by rings.
➨ SDH allows quick recovery from failure.

Drawbacks or disadvantages of SDH

Following are the disadvantages of SDH:
➨It offers lower bandwidth utilization ratio compare to PDH due to many OH bytes used for OAM.
➨Direct adding/dropping of lower-rate signal is achieved using pointers. This increases complexity of the system.
➨Software is used largely in SDH system. Hence it is vulnerable to computer viruses.
➨It requires complicated SDH equipments due to variety of management traffic types and options.
➨It can not carry E2 due to unavailability of container.