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ATM Over SONET. By: Kavitha Sriraman, CEPE, Dept of ECE, Drexel University, Email : kavitha@drexel.edu. What is ATM over SONET??. prevalent in the Computer Networking for transmitting of Internet Packets.
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ATM Over SONET By: Kavitha Sriraman, CEPE, Dept of ECE, Drexel University, Email : kavitha@drexel.edu ATM over SONET~Kavitha Sriraman
What is ATM over SONET?? • prevalent in the Computer Networking for transmitting of Internet Packets. • optical layer provides the foundation of transport services for both metro and long-haul applications. . • Transporting Layer is the ATM. ATM over SONET~Kavitha Sriraman
SONET?? • Synchronous Optical NETwork. • Synchronous, Asynchronous, Plesiochronous. • Plesiochronous difference. • Data rate ATM over SONET~Kavitha Sriraman
SONET SIGNAL. • defines a technology for carrying many signals of different capacities through a synchronous, flexible, optical hierarchy ~ Byte interleaving. • SONET multiplexing involves the generation of the lowest level or base signal- STS–1 • operates at 51.84 Mbps. • Higher-level signals are integer multiples of STS–1, creating the family of STS–N signals ATM over SONET~Kavitha Sriraman
SONET SIGNAL TABLE. ATM over SONET~Kavitha Sriraman
SONET FRAME FORMAT • divided into two main areas: transport overhead and the synchronous payload envelope (SPE). • SPE divided into two parts: the STS path overhead (POH) and the payload. • Once the payload is multiplexed into the synchronous payload envelope, it can be transported and switched through SONET without being examined and possibly de-multiplexed at intermediate nodes ~service-independent or transparent . ATM over SONET~Kavitha Sriraman
Transmission Of Signals in SONET • signal into containers. Adds the section overhead ~ signal and the quality of transmission are all traceable. • containers have two names depending on size: virtual tributary (VT) or a synchronous payload envelope (SPE). • path overhead contains data to control the facility (end to end) such as for path trace, error monitoring, far-end error, or virtual container (VC) composition. • packaged in VCs and transported in synchronous transport vehicles or signals (STS). ATM over SONET~Kavitha Sriraman
Transmission Of Signals in SONET ATM over SONET~Kavitha Sriraman
Transmission Of Signals in SONET contd.. • An STS exists on each section (i.e., the link between two nodes), also contains the line or section overhead. • This line/section overhead contains data to control the node-to-node transmission (protection switching, error monitoring), and, in addition, provides extra channels (network management and maintenance phone link). • line transmission rates are 51, 155, and 622 Mbps; 2.5 Gbps; and 10 Gbps. • Line signals can be optical or electrical. Electrical signals are used for short distances. ATM over SONET~Kavitha Sriraman
Transmission Of Signals in SONET contd.. ATM over SONET~Kavitha Sriraman
Asynchronous Transfer Mode • A high-performance, cell-oriented switching and multiplexing technology that utilizes fixed-length packets to carry different types of traffic. • fixed-length cells consisting of 48 bytes (8 bits per byte) of payload and 5 bytes of cell header ~ensures that time-critical information such as voice or video is not affected by long data frames or packets. • header is organized for efficient switching ATM over SONET~Kavitha Sriraman
ATM Connections • virtual path connections (VPCs), which contain virtual channel connections (VCCs). • A virtual channel connection (or virtual circuit) is the basic unit, which carries a single stream of cells, in order, from user to user. • All cells belonging to a particular virtual path are routed the same way through the ATM network~ faster recovery in case of major failures. • Virtual circuits can be statically configured as permanent virtual circuits (PVCs) or dynamically controlled via signaling as switched virtual circuits (SVCs)~a rich set of service capabilities. • SVCs are the preferred mode of operation ~ dynamically established ~ minimizing reconfiguration complexity ATM over SONET~Kavitha Sriraman
Structure to Carry Data • ATM cells does not have the structure. • SONET provides the VT (containers). • its filled with cells (ATM ) of 53 bytes. • Higher Data Rate ~ the cells are concatenated. ATM over SONET~Kavitha Sriraman
Conclusion…. • high performance via hardware switching • dynamic bandwidth for bursty traffic • class-of-service support for multimedia traffic. • scalability in speed and network size • provide a range of data, image, video and voice services that take advantage of increasing insensitivity of the network to distance. ATM over SONET~Kavitha Sriraman