A NEW CONGESTION CONTROL POLICY ON THE INTERNETWORKS

This paper discusses the distinction between internetworks and single network in the congestion control. It has shown the reason why all of single network’s congestion control is not suitable to internetworks. A new congestion control scheme of internetworks is presented which uses acknowledgment time-outs and the feedback signal from gateway as indications of packet loss and congestion. Using a black-box model of the internetworks, this paper derives approximate calculating formulas and proves the scheme’s special characters by computer simulation. It is shown that the presented method is better than R. Jain’s (1986).

A Formal Model of OSI X.25/FR Gateway Based on High Level Petri Net

Specification and validation of protocol conversion in a gateway is a difficult problem in protocol engineering. During design and implementation of an OSI X.25/FR gateway, a high level Petri Net called EPr/TN is introduced as a formal specification tool to solve this problem. A formal model of the gateway is constructed by using Epr/TN. Based on this model, the process of protocol conversion and data transmission in the gateway are analyzed and validated. With object oriented techniques, this model is also utilized in the software development of the gateway.

Distribution Network Equipment Location and Capacity Planning Method Considering Energy Internet Attribute from the Perspective of Life Cycle Cost

For facing the challenges brought by large-scale renewable energy having access to the system and considering the key technologies of energy Internet,it is very necessary to put forward the location method of distribution network equipment and capacity from the perspective of life cycle cost.Compared with the traditional energy network,the equipment capacity problem of energy interconnected distribution network which involves in electricity network,thermal energy network and natural gas network is comprehensively considered in this paper.On this basis,firstly,the operation architecture of energy interconnected distribution network is designed.Secondly,taking the grid connection location and configuration capacity of key equipment in the system as the control variables and the operation cost of system comprehensive planning in the whole life cycle as the goal,the equipment location and capacity optimization model of energy interconnected distribution network is established.Finally,an IEEE 33 bus energy mutual distribution grid system is taken for example analysis,and the improved chaotic particle swarmoptimization algorithm is used to solve it.The simulation results show that the method proposed in this paper is suitable for the equipment location and capacity planning of energy interconnected distribution network,and it can effectively improve the social and economic benefits of system operation.

Performance Analysis of Interconnected Communication Networks

As the means for communication of users in different communication networks and network resource sharing, communication network interconnection has been paid great attention to in recent years. The performance analysis of internetworks is very important in communication network interconnection, for it is the basis for the study of other problems concerned. The main contribution of this paper is a wide and deep study of performance of internetwork, the construction of systematic performance analysis method for arbitrary internetworks, and of queuing model for gateways. In this paper, the performance analysis of internetwork with arbitrary topology is studied for the first time, and a new method - Node Equivalence of Subnetworks (NES) is proposed. The key step of this method is the node equivalence of subnetworks of all kinds, so we first deeply study the node equivalence, and develop two models for node equivalence. Then we study the node equivalence of CSMA/CD and SLOTTED ALOHA systems by using these models. The results show that the NES method is a systematic method which is suitable for performance analysis of any type of internetworks. The proposed equivalence models is usable with good approximation. The queuing model of gateway is first widely studied in this paper. The queuing model for gateways with packet fragmentation and reassembly is studied for the first time and the analysis method, proposed. In the analysis, two modeling tools, Reversed Switched Poisson Process (RSPP) and Switched Determined Process (SDP), are proposed and RSPP/M/1 queue and SDP/D/1 queue, analyzed. A new method-minislot method is proposed and used for the study of SDP/D/1 queue and performance of ATM multiplexer. In this paper, the interdeparture time distribution of ATM network under some input traffic models is studied and the expression, derived. These results can be used for both performance evaluation of ATM network and the performance of ATM networks interconnected with other networks. We also propose an approximate analysis method for queuing networks with priority service and the queuing networks with packet fragmentation and reassembly.

Architecture and Engineering Issues in Building an IP over WDM Net works

The technologies of IP over WDM have presently received increasing attention owing to the rapid growth in Internet traffic and the need for next generation Internet technologies. The challenge now is how to integrate the services of IP over WDM optical networks to take full advantages of WDM technologies and IP technologies, and yield a high throughput optical platform directly underpinning next generation data networks. This article discusses some of the architecture and technology issues for the design of IP over WDM optical networks.