atm over sonet~kavitha sriraman1 atm over sonet by: kavitha sriraman, cepe, dept of ece, drexel...

ATM over SONET~Kavitha Sriraman 1

ATM Over SONET

By:Kavitha Sriraman, CEPE, Dept of ECE, Drexel University,Email : [email protected]


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.


SONET??

Synchronous Optical NETwork. Synchronous, Asynchronous,

Plesiochronous. Plesiochronous difference. Data rate


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


SONET SIGNAL TABLE.

Signal Bit Rate (Mbps) Capacity

STS–1, OC–1 51.840 28 DS–1s or 1 DS–3

STS–3, OC–3 155.520 84 DS–1s or 3 DS–3s

STS–12, OC–12 622.080 336 DS–1s or 12 DS–3s

STS–48, OC–48 2,488.320 1,344 DS–1s or 48 DS–3s

STS–192, OC–192 9,953.280 5,376 DS–1s or 192 DS–3s

Note: STS = synchronous transport signal; OC = optical carrier

Signal Bit Rate (Mbps) Channels

DS–0 0.640 1 DS–0

DS–1 1.544 24 DS–0s

DS–2 6.312 96 DS–0s

DS–3 44.736 28 DS–1s


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 .


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).


Transmission Of Signals in SONET


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.


Transmission Of Signals in SONET contd..

Bit Rate (Mbps)

PDH North America PDH Europe SDH SONET

Name Bit Rate (Mbps)

Name Bit Rate (Mbps)

Container Transport Container Transport

10,000 STM–64 STS/OC–192

2,500 STM–16 STS/OC–48

622 STM–4 STS/OC–12

155 STM–1 STS/OC–3

140 E4 140 VC4

51 STS/OC–1


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 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


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.


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 sriraman1 atm over sonet by: kavitha sriraman, cepe, dept of ece, drexel...

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