SDH Frame Structure

1. © 2011 Infosys Technologies Limited, India   Infosys       SDH Frame Structure November, 2011       INFOSYS TECHNOLOGIES LIMITED Pune              

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3. Author(s): Samadhan Ravindra Tambe Date written (MM/DD/YY): 11/29/11 Project Details: SDH Transmission Related PPT

4. What we will come to know after this presentation??? 1. What is SDH. 2 . Basic Frame structure of SDH. 3. How to calculate Basic Data Rate of SDH Frame using Total No. of Bits. 4. SDH Frame formation processes Mapping, Aligning, Pointer Processing etc. 5 . SDH Frame formation using Lower Level Signal (C12). Points Covered

5. What is SDH? SDH Means Synchronous Digital Hierarchy, It is a standard Protocol for transmission of data over a medium . It is designed by International Telecommunication Union i.e. ITU and it was deployed on telecommunication network in the year of 1992 . Main fundamental of SDH is to overly and transmit a Synchronous Multiplexed light stream Signal onto a Fiber Optic cable . SDH is bandwidth Flexible and it also allows Multivendor Internetworking. It has numerous advantages over traditional Transmission technologies such as PDH i.e. Plesiocronous Digital Hierarchy (PDH) . SDH signal is bandwidth Flexible and hence different types of lower order signal can be transmitted in its Virtual Container. Introduction to SDH

6. Basic SDH Signal The basic transmission format of SDH is a STM-1 Frame which is transmitted in 125 Microseconds time slot in Byte wise pattern. There are 8000 Frames Transmitted per Second . In all there are 9 Rows and 270 Columns in a STM Frame, of which first 9 Columns of each frame forms Sectional Overheads and Pointer . Remaining 261 Columns consist of Virtual Container (VC) which carries actual data. This VC along with Pointer Bytes called as Administrative Unit (AU ). As there are 270 Columns, 9 Rows having 8 Bytes total number of bytes in STM-1 Frame will be 270*9=2430 Bytes. Basic Facts About SDH

7. RSOH Pointer MSOH Payload(VC ) Regenerator Section Overhead Indicates start of Payload Multiplexer Section Overhead Actual Data POH Path Over Head This Slide will show basic SDH Frame structure…!!! SDH Frame Structure

8. RSOH Pointer MSOH Payload(VC) POH 270 Columns 261 Columns 9 Columns 5 Rows 1 Row 3 Rows Hence Total No. of Bits = 270 Columns * 9 Rows * 8 Bits = 19440 Bits Whole Frame transmitted in 125 microseconds Thus Basic Data Rate of STM Frame is = 19440/125 µs = 155.52Mbits/sec Now we will Calculate Basic SDH Data Rate by using total no. of bits…!!! Data Rate of SDH Frame

9. Mapping Adding justification bits and Path Overhead to Lower Level Signals so that they can be fit into Virtual Containers (VC’s) Vertual Container Stuffing Bits Stuffing Bits Stuffing Bits Stuffing Bits Stuffing Bits Stuffing Bits Data Bits Frame Formation Process

10. Aligning Process of arranging the Virtual container so that pointer can be added. Virtual Container Virtual Container Virtual Container POINTER ADDITION Frame Formation Process- Continued

11. Pointer Processing Process of adding Pointer to Aligned Virtual Containers. Virtual Container Virtual Container Virtual Container POINTER Frame Formation Process- Continued

12. Multiplexing Process of combining Same size Units together. Trib Unit Trib Unit Trib Unit Trib Unit Frame Formation Process- Continued

13.   SDH Digital Bit Rate Size of VC VC-11 1.728 Mbit/s 9 rows, 3 columns VC-12 2.304 Mbit/s 9 rows, 4 columns VC-2 6.912 Mbit/s 9 rows, 12 columns VC-3 48.960 Mbit/s 9 rows, 85 columns VC-4 150.336 Mbit/s 9 rows, 261 columns Table showing Virtual Containers (VC’s) Size Formation of SDH Frame using VC12 is explained in next slide Payload Container Sizes

14. C12 VC12 TU12 Signal is mapped into Container VC’s are aligned for Pointer Addition TU12 TU12 TUG2 Pointer Processing Tributary Units are Multiplexed TU12 TU12 TU12 TUG2 TUG2 TUG2 TUG2 TUG2 TUG2 TUG2 TUG 3 This Slide will explain How Tributary Unit Group3 (TUG 3) is formed from C12 ie . Lower Level Signal 7 TUG2’s are Multiplex to form TUG3 Formation Of TUG 3

15. TUG 3 TUG 3 TUG 3 VC4 3 TUG3 are Multiplexed together and placed in Higher order container VC4…!!! Pointer AU4 HO POH AUG1 VC4 is aligned for Pointer Processing Administrative Unit Group Formation

16. Payload Pointer, RSOH & MSOH Added to Auxiliary Unit Group(AUG1) and STM 1 Frame is formed POINTER MSOH RSOH HOPOH STM Frame A Complete SDH Frame- STM1

17. In Similar Way we can form SDH frame from different Lower level signals as follows AU4 Pointer Processing Multiplexing Aligning Mapping STM-N AUG AU4 VC4 TUG3 TU3 VC3 TUG2 TU2 VC2 C2 TU12 VC12 C12 TU11 VC11 C11 C4 AU3 VC3 C3 139 Mb/s 45 Mb/s 34 Mb/s 63 Mb/s 2 Mb/s 1.55 Mb/s 3 3 3 4 7 ´ 7 Frame formation with other Signals

18. Thank You…!!!

19. Target readers Project related Transmission, Fiber and SDH Sonet. Keywords SDH, Transmission, SDH Frame, SDH Basic Data Rate Introduction SDH Frame structure Presentation will introduce us to SDH and it’s basic frame structure. It also explain how SDH frame is formed from lower level signals. Reference(s ): SDH Telecommunications Standard Primer , Tektronix, 2001. © 2010 Infosys Technologies Limited, India