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?
• 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.