LAYER PROTOCOL ,SONET,SDH
- 1. SONET/SDH
- 2. 17.2 SONET was developed by ANSI; SDH was developed by ITU-T. SONET : Synchronous Optical Network SDH: Synchronous Digital Hierarchy Definition: SONET is a physical layer network technology designed to carry large volumes of traffic over relatively long distances on fiber optic cabling. The United States (ANSI) and Europe (ITU-T) have responded by defining standards that, though independent, are fundamentally similar and ultimately compatible. The ANSI standard is called the Synchronous Optical Network (SONET). The ITU-T standard is called the Synchronous Digital Hierarchy (SDH).
- 3. 17.3 ARCHITECTUREARCHITECTURE Let us first introduce the architecture of a SONETLet us first introduce the architecture of a SONET system: signals, devices, and connections.system: signals, devices, and connections. Signals SONET Devices Connections Topics discussed in this section:Topics discussed in this section:
- 5. A simple network using SONET equipment
- 6. SONET LAYERSSONET LAYERS The SONET standard includes four functional layers:The SONET standard includes four functional layers: thethe photonicphotonic, the, the sectionsection, the, the lineline, and the, and the pathpath layer.layer. They correspond to both the physical and the data linkThey correspond to both the physical and the data link layers.layers. Path Layer Line Layer Section Layer Photonic Layer Device–Layer Relationships Topics discussed in this section:Topics discussed in this section:
- 7. SONET defines four layers: path, line, section, and photonic. Note
- 8. Figure 17.2 SONET layers compared with OSI or the Internet layers
- 9. SONET layers : Path Layer Path Layer is responsible for the movement of a signal from its optical source to its optical destination. The signal is change from an electronic form to into optical form. Multiplexed with other signal. Encapsulated in a frame. STS multiplexers provide path layer functions.
- 10. SONET layers : Line Layer Line Layer is responsible for the movement of a signal across a physical line. Line layer overhead is added to the frame at this layer. STS multiplexers and add/drop multiplexers provide the line layer function.
- 11. SONET layers : Section Layer Section Layer is responsible for the movement of a signal across a physical line. It handles framing, scrambling and error control. Section layer overhead is added to the frame at this layer.
- 12. SONET layers : Photonic Layer Photonic layer corresponds to the physical layer of the OSI model. It includes physical specification for the optical fiber channel. SONET uses NRZ encoding.
- 13. Figure 17.3 Device–layer relationship in SONET
- 14. 17-3 SONET FRAMES17-3 SONET FRAMES Each synchronous transfer signal STS-n is composedEach synchronous transfer signal STS-n is composed of 8000 frames. Each frame is a two-dimensionalof 8000 frames. Each frame is a two-dimensional matrix of bytes with 9 rows by 90 × n columns.matrix of bytes with 9 rows by 90 × n columns. Frame, Byte, and Bit Transmission STS-1 Frame Format
- 15. 17.15 Figure 17.4 An STS-1 and an STS-n frame
- 16. Figure 17.5 STS-1 frames in transmission
- 17. A SONET STS-n signal is transmitted at 8000 frames per second. Note
- 18. Each byte in a SONET frame can carry a digitized voice channel. Note
- 19. 17.19 Example Find the data rate of an STS-l signal. Solution: STS-l, like other STS signals, sends 8000 frames per second. Each STS-l frame is made of 9 by (l X 90) bytes. Each byte is made of 8 bits. The data rate is STS-1 data rate = 8000 X 9 X (1 X 90) x8= 51.840 Mbps
- 20. 17.20 Example Find the data rate of an STS-3 signal. Solution STS-3, like other STS signals, sends 8000 frames per second. Each STS-3 frame is made of 9 by (3 X 90) bytes. Each byte is made of 8 bits. The data rate is STS-3 data rate= 8000 x 9 x (3 X 90) x 8 =155.52 Mbps
- 21. Advantage of SONET Increased bandwidth over traditional telecomm system Increased configuration flexibility that supports future applications, with variety of transmission rates Reduction in equipment requirement An increase in network reliability
- 22. 17.22 DRONACHARYA COLLEGE OF ENGINEERING, GURGAON Computer Science & Engineering Assignment Semester- VI (I & II) Branch: CSE Subject with Code: Computer Networks (IT-305-F) ----------------------------------------------------------------------------------------------- Q:1 What is Frame Relay? Explain SONET/SDH in detail.