1. Advantages Of SDH è More Capacity è Easy to interconnect different systems è simple and direct adding or dropping of electrical signals è Strong NMS è Flexible and self-healing networks

2. Advantages Of SDH è All current PDH signals can be transmitted within the SDH except 8 Mb/s (E2) which has no container. è A reduction in the amount of equipment & an increase in network reliability. è Compatible….PDH, ATM, DQDB

3. Disadvantages Of SDH è Lower Bandwidth utilization è Complicated SDH equipments due to variety of management traffic types and options è Software based..vulnerable to computer viruses, configuration problems, etc. è Direct add/drop needs pointer, which make it complex and introduce jitter è Can’t carry E2 due to un-availability of container

4. SDH Frame Structure 1 3 4 5 9 SOH STM-N Payload (including POH) 9×N 261×N 270×N SOH AU-PTR Block frame structure In units of byte (8 bits) Rate: 8000 frames/s, frame cycle: 125µs

5. 1st Byte Last Byte 2430 STM-1 Frame # 1 1st Byte STM-1 Frame # 2 From Left to right & top to bottom Transmission Direction STM-1 Frame Transmission 1st Byte 2430 th Byte

6. MUX REG TM Path Section MS Multiplex Section RS SDH Link Structure Regenerator Section Sub network