Hiromi Ueda

Implementation and application of equipment with network node interface

Synchronous equipment using the CCITT standard network node interface (NNI) is being developed. The equipment consists of three kinds of modules: a skip-level multiplexer which converts the existing switching and transmission system interfaces to the NNI, a TU-11 (24 CH) cross-connect device, and an STM-N skip-multiplexer with a line terminating function. These modules are implemented mainly with state-of-the-art CMOS VLSI and fiber-optic technologies. The equipment is expected to simplify the network, reduce its cost, and allow rapid provisioning. It is also expected to simplify and improve network maintenance and provide greater system versatility of services.<<ETX>>

New synchronous digital transmission system with network node interface

The authors describe a synchronous digital transmission system using the network node interface (NNI) that compiles with CCITT recommendations G.707, G.708, and G.709. To offer device independence for function enhancement and to permit a flexible network, the recommendations are implemented as modules A, B, C, and ADP. Module A is a fiberoptic line terminating multiplexer and a generator. Module B is a CV-11 cross-connect system with NNI. Module C converts the existing lower speed interfaces to NNI. ADP converts NNI to the 100-Mb/s existing interface to make use of the existing facilities. The specifications of each module are given, and field trials are discussed.<<ETX>>

Implementation and experimental results of CLAD using SRTS method in ATM networks

Timing information must be transported through an ATM network when a CBR signal, whose timing is independent of that of the network, is transmitted as ATM cells. For this purpose, ITU-T Recommendation I.363 defines the SRTS (synchronous residual time stamp) method. The authors implement a DS-3 CLAD (cell assembly and disassembly) device using the SRTS method. The SRTS method generates jitter, which is similar to the destuff jitter experienced in a stuff multiplexing system. Amplitude and spectrum of the SRTS jitter are evaluated using the DS-3 CLAD device. Finally, high speed data transmission is conducted between FDDI-LANs, and high quality NTSC video transmission is achieved using the CLAD device in an ATM field trial.

STM signal transfer techniques in ATM networks

Some of the issues of converting synchronous transfer mode (STM) signals into asynchronous transfer mode (ATM) signals and vice versa are considered. During the period when ATM and STM networks coexist, it is necessary to convey STM signals, such as virtual container signals (VC-II, VC-2 and VC-3), with ATM technologies. The STM signal transfer unit, the VC level or TU/AU level, is considered, and the best choice is found to be TU/AU. An algorithm for handling lost or misbelieved cells using the sequence number and its protection is presented. Cell delay variations are estimated using tandem M/D/1 queuing models. Two buffer control methods are considered for smoothing cell delay variations. A key point is to prevent buffer underflow. Two methods for achieving this are proposed.<<ETX>>

Synchronous digital transmission systems based on CCITT SDH standard

The synchronous digital hierarchy (SDH) transmission systems developed by NTT are discussed. The advantages of SDH are detailed, stressing its simplified network structure and enhanced operations, administration, and maintenance functions. The layered architecture of the SDH systems is described. NTTs SDH fiber-optic transmission systems and digital radio transmission systems are presented.<<ETX>>

ATM transport system architecture and field trial

The ATM link system will play an important role in constructing virtual path transport networks for the future B-ISDN. A prototype ATM link system is implemented that exhibits the benefits of ATM to the greatest possible extent. This system features not only very high-speed line interfaces, large capacity cross-connect networks, and built-in functions that contribute to efficient operation and maintenance, but also very compact equipment using state-of-the-art technologies. The paper describes the B-ISDN network architecture, ATM link system role in the networks, newly developed technologies, and the implemented system.<<ETX>>

New Optical Access Network Architecture Using Optical Packet Switches

This paper proposes a new optical access network architecture that differs from those of conventional Point-to-Point (PP) and Passive Optical Networks (PON). The proposed architecture, Optical Switched Access Network (OSAN), uses Optical Switching Modules (OSMs) that connect an Optical Line Terminal (OLT) to Optical Network Units (ONUs) in a virtual point to point configuration so that it offers the merits of both PP and PON while overcoming their demerits. Each OSM optically switches packets of variable length one by one under electrical control. To allow the elimination of optical buffers from OSM, OSAN uses the Multi-Point Control Protocol (MPCP) defined in IEEE 802.3ah. We evaluate the transmission distances between OLT and ONUs, and consider a network synchronization scheme and discovery mechanism that supports MPCP.

Design of optical switching module for gigabit ethernet optical switched access network

This paper introduces the design of an Optical Switching Module (OSM) for our newly proposed Gigabit Ethernet Optical Switched Access Network (GE-OSAN) architecture that uses the Multi-Point Control Protocol (MPCP), defined in IEEE 802.3ah. We outline the GE-OSAN architecture to clarify OSMs role in the network. We offer an OSM configuration that has the basic functions needed to realize downstream and upstream high-speed data services in GE-OSAN. We clarify the OSM optical switching time that allows GE-OSAN to achieve the same throughput as GE-PON. Our survey of currently available optical switches identifies the optical packet switches that can meet this switching time requirement. We evaluate OSM insertion loss with these switches. We propose an OSM configuration that has a regeneration function as well as the basic ones to realize wider network configurations that can lead to a reduction in overall system costs. In addition, we present OSM configurations that have broadcast and multicast functions as well as the basic ones so that GE-OSAN can support broadcast and multicast video services to equal and exceed GE-PON.

Virtual path management functions for broad-band ATM networks

Virtual path management functions and their mechanisms, which are of importance for effective ATM (asynchronous transfer mode) networks, are proposed. Four major management functions are introduced: maintenance signal transfer, performance monitoring, virtual path testing, and virtual path tracing. Mechanisms for the proposed maintenance signal transfer function are described.<<ETX>>

Novel optical packet switched access network architecture

This paper describes gigabit Ethernet optical switched access network (GE-OSAN) architecture with non-buffered 1xn optical packet switches. It clarifies the role of the key network element, 1xn optical switching module, in realizing the proposed architecture.