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[attachment=3039]
A SEMINAR REPORT ON
ASYNCHRONOUS TRANSFER MODE(ATM)
INTRODUCTION
High performance, cell-oriented switching and multiplexing technology
Utilizes fixed-length packets to carry different types of traffic
Helps in efficient multimedia applications, high-speed LAN connections and used in broad range of networking
devices
OVERVIEW
BENEFITS OF ATM
high performance via hardware switching
dynamic bandwidth for bursty traffic
class-of-service support for multimedia
scalability in speed and network size
common LAN/WAN architecture
opportunities for simplification via VC architecture
international standards compliance
ATM CELL HEADER FORMAT
ATM REFERENCE MODEL
ATM ADDRESS FORMAT
ATM SERVICE CLASSES
constant bit rate (CBR)
variable bit rate non-real time (VBR NRT)
variable bit rate real time (VBR RT)
available bit rate (ABR)
unspecified bit rate (UBR)
ATM TECHNICAL PARAMETERS
cell loss ratio (CLR)
cell transfer delay (CTD)
cell delay variation (CDV)
peak cell rate (PCR)
burst tolerance (BT)
sustained cell rate (SCR)
ATM STANDARDS
A cohesive set of specifications that provide a stable ATM framework.
Provide the end-to-end service definitions
An important ATM standard is interworking between ATM and frame relay
Two ATM networking standards
1)broadband intercarrier interface (B ICI) 2)public network-to-network interface (P NNI)
DATA INSERTION SCHEMES
RFC1483-specifies how interrouter traffic is encapsulated into ATM
LANEMPOA- support dynamic use of ATM SVCs
voice and video adaptation schemes-for efficient traffic that no natural breaks, such as a circuit carrying bits
at a fixed rate
ATM LAN EMULATION(LANE)
VIDEO OVER ATM
Handled by VBR RT VCs using AAL 5 for MPEG2 on ATM for video-on-demand applications
MPEG2 coding can result in two modes:
program streams variable-length packets carrying single or multiple programs
transport streams 188-byte packets that contain multiple programs
Time stamps are inserted into MPEG2 packets during the encoding and multiplexing process to make better use of
networking resources.
VOICE OVER ATM
VBR RT connections is used over ATM which uses silence period.
Various dynamic compression techniques are used to free bandwidth and alleviate congestion
A further enhancement is to support voice switching over SVCs which interprets PBX (private branch exchange)
signaling and routing voice calls to the appropriate destination PBX
NETWORK TRAFFIC MANAGEMENT
objectives :To deliver quality-of-service (QoS) for multimedia applications and provide overall optimization of
network resources.
categorized into three distinct elements
nodal-level controls that operate in real time
network-level controls operate in near real time
network engineering capabilities operating in non real time
ATM APPLICATIONS
ATM AND IP INTERWORKING
ATM and IP offer: Scalability, traffic engineering, service differentiation, high availability, value-added
applications such as Virtual Private Networks (VPNs)
Some specifications of ATM and IP
Multi-Protocol over ATM (MPOA) as addition to LAN Emulation (LANE)
Additions to ATM's superior routing protocol PNNI
adoption of Frame-based ATM over Sonet/SDH (FAST)
CONCLUSION
ATM technology is the only technology that can guarantee a certain and predefined quality of service.
The growth of the Internet, need for broadband access and e-commerce are spurring the need for a reliable,
flexible, scalable, predictable, versatile transport system and that is given by ATM Technology.
For voice, video, data and images together, the next generation network depends on ATM.
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Definition
These computers include the entire spectrum of PCs, through professional workstations up to super-computers. As the performance of computers has increased, so too has the demand for communication between all systems for exchanging data, or between central servers and the associated host computer system.The replacement of copper with fiber and the advancement sin digital communication and encoding are at the heart of several developments that will change the communication infrastructure. The former development has provided us with huge amount of transmission bandwidth. While the latter has made the transmission of all information including voice and video through a packet switched network possible.
With continuously work sharing over large distances, including international communication, the systems must be interconnected via wide area networks with increasing demands for higher bit rates.
For the first time, a single communications technology meets LAN and WAN requirements and handles a wide variety of current and emerging applications. ATM is the first technology to provide a common format for bursts of high speed data and the ebb and flow of the typical voice phone call. Seamless ATM networks provide desktop-to-desktop multimedia networking over single technology, high bandwidth, low latency network, removing the boundary between LAN WAN.
ATM is simply a Data Link Layer protocol. It is asynchronous in the sense that the recurrence of the cells containing information from an individual user is not necessarily periodic. It is the technology of choice for evolving B-ISDN (Board Integrated Services Digital Network), for next generation LANs and WANs. ATM supports transmission speeds of 155Mbits / sec. In the future, Photonic approaches have made the advent of ATM switches feasible, and an evolution towards an all packetized, unified, broadband telecommunications and data communication world based on ATM is taking place.
These computers include the entire spectrum of PCs, through professional workstations upto super-computers. As the performance of computers has increased, so too has the demand for communication between all systems for exchanging data, or between central servers and the associated host computer system.
The replacement of copper with fiber and the advancement sin digital communication and encoding are at the heart of several developments that will change the communication infrastructure. The former development has provided us with huge amount of transmission bandwidth. While the latter has made the transmission of all information including voice and video through a packet switched network possible.
With continuously work sharing over large distances, including international communication, the systems must be interconnected via wide area networks with increasing demands for higher bit rates.For the first time, a single communications technology meets LAN and WAN requirements and handles a wide variety of current and emerging applications. ATM is the first technology to provide a common format for bursts of high speed data and the ebb and flow of the typical voice phone call. Seamless ATM networks provide desktop-to-desktop multimedia networking over single technology, high bandwidth, low latency network, removing the boundary between LAN WAN.
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Asynchronous Transfer Mode (ATM)
ATM
Definition
Acronym for automated teller machine, a machine at a bank branch or other location which enables a customer to perform basic banking activities (checking one's balance, withdrawing or transferring funds) even when the bank is closed.
Read more: http://investorwords308/ATM.html#ixzz1Zz5X2CDE
ATM Introduction
Asynchronous Transfer Mode (ATM) is the CCITT standard for broadband ISDN. It supports integrated voice, data, and video communications both for services available and for future services not yet defined [12] [6]. In ATM the information to be transmitted in divided into short 53 byte packets or cells, which have a 5 byte header. The reason for such a short cell length is that ATM must deliver real time service at low bit rates and thus it minimizes packetization delay. ATM networks are connection oriented with virtual channels and virtual paths. The virtual channel carries one connection while a virtual path may carry a group of virtual channels. This ensures that cell sequence is maintained throughout the network. The virtual channel is identified by the Virtual Channel Identifier, (VCI), and the virtual path is identified by the Virtual Path Identifier, (VPI). Both the VCI and VPI may change within the network and they are stored in the header of the cell. There is a Payload Type, (PT), field in the header which indicated whether the cell is user data or connection management information and also to indicate congestion in the network. There is also a Cell Loss Priority, (CLP), bit which is set high to indicate that the cell is low priority and set low to indicate high priority. There is a Generic Flow Control, (GFC), field which is for further study, but is essentially used for controlling the source to network connection. The whole header is protected an eight bit CRC contained in the Header Error Control, (HEC), field. The typical header therefore looks like that shown in Figure 2 for the user to network interface as specified by the ATM Forum [1].
As ATM will be a broadband service the network will be a high speed one. To lessen the effect of the relatively slow processors within the network only a subset of functions will be carried out in the network. Error detection, correction, and flow control are done at the network edge rather than within the network. At the start of a call to set up a connection in terms of a virtual channel, there is negotiation between the user and the network on the parameters. Once admission is achieved the call is then monitored to ensure that it is compliant with the call setup paprameters. The network may drop low priority cells if congestion is about to or has occured. High priority cells may only be dropped when there are no lower priority cells left to drop. Services not sensitive to cell loss may have some low priority cells and these cells may be dropped. Because of this it is possible to get much higher utilisation than with previous networks
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A detailed seminar document (.ppt and .doc)on Asynchronous Transfer Mode (ATM) , which is an International Telecommunication Union Telecommunication Standardization Sector (ITU-T) standard for cell relay wherein information for multiple service types, such as voice, video, or data, is conveyed in small, fixed-size cells. ATM networks are connection oriented.
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plz send me more information about asychronous transfer mode pdf,ppt,doc
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plz tel me how to download the asynchronous transfer mode ppt,pdf,doc
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