Integrated Switching System Research Articles

Tradeoff study among traffic egression schemes and member allocation optimization for link aggregation groups in integrated switching systems

An integrated switching system (ISS) is an integration of individual switching devices with newly developed control and management protocols, in an integration topology that interconnects the switching devices. It scales the capacity of individual switching devices while functions still as a single switching facility to the outside network. In an ISS, a link aggregation group (LAG) has flexibility to allocate its member links across different switching devices, often as an attempt to spread risk of failure to individual switching devices. Due to existence of the integration topology, traffic admitted into the ISS and destined to egress out of the LAG interface may need to travel a number of hops before leaving the ISS. This lays a bandwidth burden on the integration links of the ISS. Local biasing and designated forwarding have been proposed as LAG egression options to relieve the bandwidth pressure on integration links. They bias traffic egression to be from the neighborhood of the switching device where the traffic ingresses, if the traffic is destined to the LAG interface and a LAG member link is present in the neighborhood. Those enhanced LAG egression schemes are in contrast to the regular LAG egression scheme, in which the traffic will be split and evenly distributed across all LAG members, regardless of their topological distance to the switching device where it ingresses. Although the enhanced egression schemes help to reduce the bandwidth demand on the integration links, there comes a price that load balance across LAG members may be sacrificed and eventually stable LAG capacity could be compromised. In this paper, we study such performance tradeoff and investigate impact factors on LAG performance. In the end, we formulate an optimization problem that optimizes LAG member allocation via pursuing the best tradeoff between integration bandwidth utilization and stable LAG capacity. The solution can be treated as a guideline to deploy LAGs in an ISS. The results show, with optimized LAG member allocation, the potential of integration bandwidth saving and stable LAG capacity maintenance can be maximally explored.

Elastic basket switching

AbstractThis paper proposes a new integrated switching system, ‘elastic basket switching’, for broadband and multimedia communications, including voice and high‐speed data.In elastic basket switching (EBS), it is possible flexibly and efficiently to handle multimedia information by adaptively assigning communication resources according to communication requests and bandwidth of switched information. For continuous information, such as voice, EBS functions just as a circuit switching system, and for burst data it achieves high‐efficiency bandwidth usage equivalent to a packet switching system by demand‐assign type time‐slot assignment.The detail of EBS and its application to a departmental system‐orientated PBX are described. The traffic handling capability and details of the hardware structure are presented. The experimental system, including use of LSIs in the main parts of EBS is also described.

Integrated-Circuit and Packet-Switching Applications to a Loop System for Local Area Networks

The Universal Link System belongs to the loop subsystem of a local area network (LAN). This system has circuit-switching facilities and packet-switching facilities, and uses a local area network as an integrated switching system. The Universal Link System is well suited for a very wide range of uses, with the merits of both circuit switching and packet switching. The Outline of this system is described below.

Microprogramming techniques in front-end processors of the PROTEO Digital Switching System

The Proteo transit exchange is a modern integrated switching system with a PCM switching network and a control structured in the following three hierarchical levels: • - the first level, responsible for the scanning, signalling pre-processing and translation; • - the second level dedicated to call handling, switching control and system recovery; • - the third level performing operation and maintenance tasks. The first control level is realized by several front-end processors (FEP's), specialized for telephone functions. The FEP's are located in TN16 between the switching network and the second control level (named Central Control), which consists of two parallel telephone oriented computers. The paper discusses the telephone requirements and describes an optimal partitioning of hardware, firmware and software for each type of FEP. Particular emphasis has been given to the microprogramming techniques adopted in the various control architectures. The choice of a particular architecture depends on the application. An other topic discussed in the paper is reliability which in telephone switching is required at a high degree; all the FEP's are provided with on-line diagnostic programs in order to detect faults and to perform system recovery.

Integrated Digital Switching System with Queueing Storage Facility

This paper outlines the features of a new integrated switching system for voice and data. It is composed of integrated subscriber terminals, integrated subscriber lines, an integrated digital switching system, and integrated storage facilities. This paper shows that the introduction of the integrated storage facility can create various new service utilities and improve the traffic capacity of the system.