Asynchronous Transfer Mode (ATM)

[project topics]

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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.