SMS网间互通解决方案

短消息业务（SMS）正在成为电信运营商一项重要的收入来源,他们越来越深刻认识到由短消息业务所带来的好处。据IDC的最新市场调查结果显示：全球运营商每月通过短消息业务获得的利润高达2.5亿欧元。欧洲的ＧＳＭ运营商８％～２０％的收入来源于短消息,其中,芬兰的手机用户每月的话费中约５０％出自短消息服务。在２０００年１２月全世界就发送了大约１５０亿条短消息,而沃达丰集团称仅在２００１年新年这一天就发送了１１００万条短消息。在欧洲,各主要电信运营商已经普遍实现短消息网间互连互通,正是这种普遍性的网间业务的互连互…     

中国联通对网间互联的展望

过去的六年，经过政企分离、电信重组、加强管制、建立运营公司的互联互通的工作机构，出台一系列的法规，促进了观念转变，使电信运营公司间的互联互通工作有了突破性进展。张春江副部长指出，电信网间的互联互通不仅是电信市场改革和开放的重要条件，更是一种首要条件，它已成为衡量我国电信改革成功与否的关键。在电信市场改革和开放过程中要解决的主要矛盾之一就是解决好互联互通问题。中国联通经过了几年的发展，互联互通有了显著的改善，中国联通移动通信的GSM和CDMA两个网分别与中国电信和中国移动的325个本地网实现了互联。中国…     

香港互联互通新政策要点

2001年9月11日，香港电讯管理局在电讯盈科的请求下发布了咨询文件，对原有的互联互通及相关竞争政策进行了探讨，以适应竞争环境变化的要求。2002年3月18日，电讯管理局发布修订后的“电讯局长声明”，就固定网络运营商之间的关系、网络互连的配置架构及基本原则、互连网络之间的通信交换、网络运营商之间的收费原则，以及互联点等相关原则进行了阐述。本文就声明中的部分内容作简要介绍。固网运营商之间的关系香港电讯管理局向固定电信网络的经营者发放固定电讯网络服务（FTNS）牌照，FTNS牌照要求持牌商：（在香港的固定点之间或在香…     

Voice service interworking for PSTN and IP networks

This article presents an overview of the main technical problems to be addressed for the provision of interoperable services between IP telephony and the PSTN. The pivotal element of the solution resides in an interworking function. This function is typically implemented in a gateway whose requirements and behavior are here analyzed in terms of signaling and control protocols (control plane) as well as user data transfer (user plane). The presentation is structured around these two planes. The control plane defines the set of signaling protocols to be used in each networking context and the translation between them. Detailed scenarios illustrate the signal translation in the gateway allowing for the establishment of a hybrid phone call. The user plane is responsible for adapting the user data to the properties of each network channel and determines the quality of service of the voice call in terms of delay and speech quality     

MPLS-TP分组传送网与现有网络互联互通的实现

在光传送网向分组传送网演进的过程中,网络之间的互联互通是运营商关心的主要问题之一.文章简要介绍了MPLS-TP(MPLS Transport Profile)分组传送网的网络构成,分析了在多种传送网并存的情况下,基于MPLS-TP分组传送网的多层网络结构,重点讨论了MPLS-TP分组传送网与IP/MPLS网络以及SDH/MSTP网络之间互联互通的实现方案.     

Frame Relay to ATM interworking

Frame Relay is a well-established technology that has attracted a large number of customers world-wide. It is typically used to interconnect large, multi-site company local area networks (LANs). These data connections are usually at low to medium speeds. Asynchronous transfer mode (ATM) is a newer, broadband technology that is capable of very high speed LAN interconnection. In addition, it is arguably an ideal transport medium for legacy protocols such as Frame Relay.This paper describes the data transport features of each technology and discusses how ATM may be used to interconnect existing Frame Relay networks, and how an ATM user may exchange data with a Frame Relay user.     

Networking over multi-hop cognitive networks

Current wireless networks feature fixed spectrum assignment policies, according to which licensees are granted the rights for the use of frequency bands on a long-term basis over vast geographical regions. Moreover, the huge success of wireless applications has prompted the exponential growth of unlicensed band usage, thus causing possible wireless spectrum shortage. Part of the problem is that spectrum usage is not uniform (according to FCC, only 15 to 85 percent of the licensed spectrum is utilized on average).     

A novel congestion control model for interworking AAA in heterogeneous networks

In the 3rd generation partnership project (3GPP) and wireless local area network (WLAN) interworking networks, 3GPP authentication, authorization, accounting (AAA) server located in 3GPP core network will be responsible for the AAA request from WLAN access network (AN). However, centralized AAA deployment is bound to give rise to the single point failure, resulting in system congestion. In order to solve this problem, this paper presents a novel congestion control model for AAA. In addition, through analyzing the model, the conclusion can be drawn that the average congestion rate of extensible authentication protocol (EAP) user request is related with factors, such as the arrival rate of EAP request, the number of EAP re-authentication, and the system buffer queue length. Finally, the simulation results show that EAP request arrival rate is directly proportional to the congestion rate, and when the number of EAP re-authentication and system buffer queue length are fixed, the number of corresponding user authentication vectors should be directly proportional to the EAP request arrival rate, so as to ensure the average congestion rate of EAP request is less than 0.005.     

Afterword: Evolving towards OSI

Open Systems Interconnection (OSI) will be achieved gradually by evolution over the next decade. The initial standards required to achieve simple systems interconnection for file transfer and message handling will be finalized by the end of 1984. Government and industry are cooperating to provide the single family of standards which users need. Computer manufacturers and network providers are planning to provide evolutionary growth paths to OSI for their users. A major U.S. national demonstration of OSI is planned for 1984. By the end of the decade, open systems information exchange will be commonplace in North America, Europe, and Japan.     

Integrating ISDN and OSI: an example

A successful multivendor trial demonstrating the integration of Open Systems Interconnection (OSI) and integrated services digital network (ISDN) technologies is discussed. The planning, staging, and results of this trial, which demonstrated ISDN as a viable transport technology for OSI data applications, are detailed. The technical requirements to be fulfilled and the initial plans are outlined. The actual configuration used is described, and the results are summarized     

OSI session layer: Services and protocols

This paper describes the principles of the Session Layer of Open Systems Interconnection and the current standardization status. The Session Layer provides the means necessary for cooperating Presentation-entities to organize and synchronize their dialogue, and to manage their data exchange. To do this, the Session Layer provides services to establish a session connection between two Presentation-entities, and to support orderly data exchange interactions.     

如何开创互联互通的新局面

互联互通是多家运营商进入电信市场，展开竞争而带来的热门话题。今天的互联互通已远远超出了如何实现网络互联和业务互通的范围，我们应从经济发展的客观规律出发，重新审视互联互通究竟给运营商带来了什么？如何看待互联互通的经济性和实质内容？目前的症结在哪？互联互通如何实现双赢互联互通是电信市场开放的重要条件。通过互联互通，新进入市场的电信业务运营商无需斥巨资建设完整的通信设施，就能经济有效地利用原电信运营目前的普遍看法是，互联互通对于有效地利用国家通信网资源、促进电信市场竞争、提高通信服务水平，都具有不可替…     

SS7 over IP: signaling interworking vulnerabilities

Public telephony - the preferred choice for two-way voice communication over a long time - has enjoyed remarkable popularity for providing acceptable voice quality with negligible connection delays, perhaps due to its circuit-switched heritage. Recently, IP telephony, a packet-based telephone service that runs as an application over the IP protocol, has been gaining popularity. To provide seamless interconnectivity between these two competing services, the Internet Engineering Task Force (IETF) has designed a signaling interface commonly referred to as SIGTRAN. This seamless intersignaling provided by SIGTRAN facilitates any subscriber in one network to reach any other subscriber in the other network, passing through any heterogeneous maze of networks consisting of either of these. Unfortunately, the same intersignaling potentially can be exploited from either side to disrupt the services provided on the other side. We show how this can be done and propose a solution based on access control, signal screening, and detecting anomalous signaling. We argue that to be effective, the latter two should consider syntactic correctness, semantic validity of the signal content, and the appropriateness of a particular signal in the context of earlier exchanged messages     

The OSI network layer: Standards to cope with the real world

Two key aspects of the OSI Network Layer which require standardization are the definition of the "service" provided by the Network Layer to the Transport Layer and the specification of the way in which "real networks" are to be utilized to provide this "Network Service." This paper describes the results of the work to date by CCITT and ISO in these two very important areas: 1) the Network Service Definition which is near final agreement; and 2) the emerging Network Layer "internal architecture" which is being used to discuss and develpoment strategies for internetworking with real networks.     

Security aspects of 3G-WLAN interworking

Third-generation cellular systems will provide wide coverage and nearly universal roaming, but will not realistically live up to the bit rate expectations placed on them. On the other hand, WLAN systems already offer bit rates surpassing those of 3G systems, but are often found lacking with respect to roaming and mobility support. In short, WLAN systems are great for hot spot coverage, while 3G systems provide global coverage and the necessary network and management infrastructure to cater for security, roaming, and charging requirements. The focus of the article is on security aspects of 3GPP-WLAN interworking.     

Probabilistic testing of OSI protocols

Protocols are large and complex software systems. Complete conformance testing of an implementation against its standard may not be feasible in terms of the resources available. This paper discusses a new approach, the P-method, to the testing of meaningful subsets of communication protocols for an asynchronous model of communication. The approach is based on the probabilistic verification of protocols, which is carried out on the more probable part of the protocol first. The technique can be used for generating probabilistic test sequences for the conformance testing of communication protocols to standards. The proposed method yields meaningful protocol test sequences which test the most probable behaviors of a protocol when the testing of the complete protocol is not feasible. Probabilistic test sequences can be categorized into different classes. The higher the class a probabilistic test sequence is in, the larger the extent of the protocol it covers, and the better is the fault coverage. If the class of a test sequence is high enough, its fault coverage is comparable to the fault coverage of test sequences generated by other methods. Results from a study of the P-method, using alternating bit protocol (ABP) and a subset of NBS TP4 as examples, support the claims above. It can also be shown that if errors are introduced only to the more probable part of the protocol, the fault coverage of P-method is also comparable to other methods     

Technology interworking for SMDS: from the DXI/SNI to the ATM UNI

As service providers introduce asynchronous transfer mode (ATM) into their networks, they are faced with the issue of technology interworking: for a given service, can a customer who has an ATM user-network interface (UNI) communicate with a customer who does not have an ATM UNI? For switched multimegabit data service (SMDS), technology interworking is well defined. In fact, SMDS is supported by several technology platforms that can interwork with each other. The three major platforms which support SMDS are: a frame-based platform based on the SMDS data exchange interface (DXI), a cell-based platform based on the IEEE 802.6-1990 standard, and a cell-based platform based on ATM. This article examines how SMDS is supported by each of these platforms and how these platforms interwork. Furthermore, this article presents how the major interworking functions required for these platforms appear to be straightforward for suppliers to implement,