ATM Adaptation Layer Research Articles

Packet reassembly during cell loss

Asynchronous transfer mode (ATM) is a packet switched data transport system based on short, fixed length cells. Each cell carries a virtual channel indicator (VCI) and virtual path indicator (VPI) in its header. Essential to the services offered by the ATM networks is the ATM adaptation layer (AAL), an ITU-TSS defined layer that adapts the cell-based ATM physical layer to packet, datagram, or bit-stream-oriented higher layers. Failure modes causing cell loss along a virtual connection are examined, and the ways AALs cope are analyzed. The sources of cell loss and their effects on AAL3/4 or AAL5 type of service are described. The usefulness of the ability of AAL3/4 to pass fragments of corrupted data up to higher layer protocols is discussed, and the implementation of selective cell discarding within switching nodes is considered, and the limitations imposed by each AAL are examined. >

B-ISDN and the OSI protocol reference model

The evolution of public telecommunication networks toward broadband integrated services digital networks (B-ISDNs) is presented. The asynchronous transfer mode (ATM), which supports B-ISDNs, and the B-ISDN protocol reference model are discussed. It is shown that the service offered by the ATM layer in the B-ISDN protocol reference model is equivalent to the service offered by the OSI physical layer. It is also shown that the service offered by the ATM adaptation layer (AAL) type 3/4 is similar to an OSI data link service. The emergence of the metropolitan area network (MAN) standard as an intermediate support for broadband services and the similarities between the DQDB MAC and the AAL type 3/4 in its connectionless mode are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Multiprotocol ATM/AAL network interface

The architecture of an experimental prototype ATM/AAL network interface that performs ATM and ATM adaptation layer (AAL) processing is described. Using a single generic architecture, the interface handles several different AAL transfer protocols supporting both constant and variable bit rate services on a per cell basis. The prototype interface is implemented using FPGAs and off-the-shelf components.

Prototyping an ATM adaptation layer in a multimedia terminal

AbstractThis paper describes the implementation of a prototype ATM adaptation layer (AAL) within the kernels of two machines running Sun Operating System 4.1.1. The implementation is achieved by using the STREAMS paradigm and an Ethernet link between the two machines as a surrogate optical fibre link. The flexibility of the STREAMS facility for building layered protocols, and the real‐time performance limitations of the STREAMS scheduling system are identified. STREAMS is shown to be no less susceptible to naïve buffer utilization than earlier paradigms. It is necessary to minimize message passing and copying of data to achieve high throughput. This study has clarified several key issues in the functional design of AALs.

SEAL detects cell misordering

The performance of a 32 bit cyclic redundancy check (CRC) for detecting cell misordering in an asynchronous transfer mode adaptation layer, called simple and efficient adaptation layer (SEAL), is discussed. It is shown that 32 bit CRC used in SEAL provides robust detection of cell misordering. For any frame size up to 4 Gb, the probability of undetected misordering is 2/sup -32/. >

The infrastructure for gigabit computer networks

The key features of the synchronous optical network (SONET) and asynchronous transfer mode (ATM) standards for the broadband integrated services digital network (B-ISDN) public network, which is expected to provide a powerful and ubiquitous infrastructure to support the emerging gigabit-per-second data and multimedia applications, are reviewed. The advantages of ATM, the ATM cell format, the B-ISDN protocol reference model and the ATM layer, the ATM adaptation layer, and ATM traffic management and signaling are discussed. An experimental high-performance parallel interface (HIPPI)-ATM-SONET interface is presented as an example to illustrate how the SONET and ATM techniques can be used to provide end-to-end transport for applications requiring a bandwidth of 800 Mb/s and possibly 1600 Mb/s.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Structure packing of coded video signals for ATM networks

AbstractIn asynchronous transfer mode (ATM) networks, a cell loss may occur and cause burst errors or synchronization slips which damages the decoded picture. Therefore, some type of cell‐packing method is required which minimizes the picture deterioration.A structured packing for coded video signals is proposed which achieves a short packing delay and high transmission efficiency. The method is based on the structure of coded video signals and makes use of cell synchronization for coded data synchronization.The characteristics of the method have been analyzed by simulations using actual TV pictures and the effectiveness of the method has been shown. This method can be discussed from the viewpoint of the ATM adaptation layer.

Error detection and correction options for data services in B-ISDN

The authors investigate error detection and correction options for data services in the broadband integrated services digital network (B-ISDN). They discuss and analyze different options for error detection and correction by considering the various alternatives ranging from no error protection to only error detection. Based on the analysis and results presented, a per-cell cyclic redundancy check (CRC) has been adopted in the adaptation layer for all data services. The authors focus on the ATM (asynchronous transfer mode) adaptation layer (AAL) error protection alternatives available within the framework of a per-cell CRC. The ATM cell header and AAL fields are described. A 4 bit cell sequence number for detecting cell misordering is analyzed. Based on the analysis, it is concluded that the 4 bit sequence number provides a powerful capability for detection of cell misordering.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>