Advantages of PDH | disadvantages of PDH
This page covers advantages and disadvantages of PDH. It mentions PDH advantages or benefits and PDH disadvantages or drawbacks. It also describes PDH basics.
What is PDH?
• PDH is the short form of Plesiochronous Digital Hierarchy.
• It is associated with digital exchanges.
• The different hierarchies having different rates are combined using PDH. There may be 24 or 30 or multiple of these channels in tributaries.
• Inputs having same rates but are from different clock sources are combined in PDH.
• There are 30 channels in Europe, 24 channels in North America. Japan uses different levels of PDH.
• Bit interleaving is used to combine signals.
Refer PDH versus SDH >>.
Benefits or advantages of PDH
Following are the benefits or advantages of PDH:
➨It was designed to support transportation of huge amounts of data over digital equipments using various transmission mediums such as microwave radio or fiber optic systems.
➨Network management has been enhanced to greater extent.
➨It performs well in North America, Europe and Japan independently as per standard specifications.
Drawbacks or disadvantages of PDH
Following are the disadvantages of PDH:
➨ In PDH, different frame is used for transmission and in data layer. Hence multiplexing and de-multiplexing is very complex.
➨ Accessing lower tributary requires the whole system to be de-multiplexed.
➨ The maximum capacity for PDH is 566 Mbps, which is limited in bandwidth.
➨ Tolerance is allowed in bit rates.
➨ PDH allows only Point-to-Point configuration.
➨ PDH does not support Hub.
➨ Every manufacturer has its own standards; PDH also has different multiplexing hierarchies making it difficult to integrate interconnecting networks together.