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这两天利用工作之外的时间帮一个研究生同学翻译了一篇小论文——iGSM，即网络电话。这个主题很有意思，而且贴近生活，是近年来的一个趋势。趁此机会可以了解下这方面的技术知识。这篇论文应该属于“网络通信”领域，与我所从事的半导体电子还是有很大不同的。所以在翻译时也是狠下了工夫，但由于时间有限，也不知翻译的准不准确。希望这个领域的同行能指点指点。下面我就以表格的形式陆续把原文和译文贴出来，恳请专家提出宝贵意见：

 

英文	中文
Headline：iGSM: VoIP Service for Mobile Networks	标题：iGSM：移动网络的VoIP业务
ABSTRACT This article proposes iGSM: a voice-over-IP value-added service for mobile network. The iGSM service provides user mobility to sub­scribers, which allows them to use either GSM handsets or H.323 terminals (IP phones or PCs) to access telecommunications services. We describe how the iGSM registration, deregistra­tion, and call delivery procedures can be imple­mented without modifying the GSM network. We study how the tromboning effect in the stan­dard GSM system can be avoided when access­ing the IP network. Then we investigate the misrouting problem caused by user mobility.	摘要 本文提出了在移动网上实现VoIP等增值业务的iGSM技术，它为用户提供了移动性（mobility），使得他们可使用GSM手机或H.323终端（IP电话或PC）获得电信服务。讨论了在不改变现有的GSM网络的前提下，iGSM如何注册、撤销注册和呼叫传递（call delivery）。此外还探讨了在接入IP网络时如何避免在标准GSM系统中产生拉长号效应（tromboning effect）以及由用户移动性导致的错打（misrouting）问题。
INTRODUCTION Supporting telephony services over IP network, or so-called voice over IP (VoIP), is considered a promising trend in the telecommunications business. Particularly, integrating mobile phone services with VoIP is becoming an important issue which has been intensively studied.	概述 在电信业务中，支持IP网络电话服务或者所谓的“VoIP”是电信业务的一种趋势。手机业务与VoIP的集成尤其成为重要的研究课题。
Telecommunications and Internet Protocol Har­monization over Network (TIPHON) specifies a mecha­nism (i.e., mediation gatekeeper) to provide the service control functions for convergence of the IP network, mobile network, fixed wireless, and public switched telephone network (PSTN). Sev­eral scenarios are defined in TIPHON to illus­trate different ways to integrate IP and mobile networks. In this article we use the Global Sys­tem for Mobile Communications (GSM) as an example of mobile networks to describe mobile/IP integration where the mobile signaling protocol is GSM Mobile Application Part (MAP).	“网络上电信与互连网协议的协调（TIPHON）”确定了一种方案（即，调停网守），让它为IP网络、移动网络、固定无线网和公共交换电话网（PSTN）之间的融合提供业务控制功能。TIPHON中定义了多种方案，用于说明集成IP网和移动网所采用的几种不同方法。在本文中，我们以GSM为例，介绍了手机/ IP的集成方案，在该方案中，手机信令协议是GSM移动应用单元（MAP）。
Our discussion applies to other mobile sig­naling protocols such as Electronics/Telecommu­nications Industry Association (EIA/TIA) IS-41 [4].The elements in the GSM network include the mobile station (MS), base transceiver station (BTS), base station controller (BSC),mobile switching center (MSC), home location register (HLR), and visitor location register (VLR).	此外，本文还讨论了其他手机信令协议，像电子/电信工业协会IS-41（EIA/TIA IS-41）。GSM网络的组件包括移动台（MS）、基站收发信台（BTS）、基站控制器（BSC）、移动交换中心（MSC），归属位置寄存器（HLR）和拜访位置寄存器（VLR）。
A TIPHON scenario that integrates mobile and IP networks to support terminal mobility is described below. The architecture for this sce­nario is illustrated in Fig. 1a, where the media­tion gatekeeper serves as a VLR to support roaming management. The BSC/BTS in the IP network provides wireless access to the IP net­work. Another TIPHON scenario describes mobile and IP integration to support user mobil­ity. We will elaborate on this scenario later.	下面就介绍集成了移动网和IP网用于支持终端移动性的TIPHON方案。该方案的体系结构见图1，其中调停网守用作支持漫游管理的VLR。IP网络中的BSC/BTS提供无线接入IP网络。另外一种TIPHON方案是集成了移动网和IP网用于支持用户移动性的方案。我们之后会详细介绍这种方案
Based on a concept similar to TIPHON, GSM on the Net [2] utilizes a corporate intranet to integrate an enterprise communications network with the public GSM network. This system sup­ports user mobility where, by using various types of terminals, a user can move around the service area without losing contact with the system. The GSM on the Net architecture is illustrated in Fig. 1b, and consists of GSM and corporate net­works.	“GSM on the Net”的理念类似于TIPHON，它利用一个企业内部网（intranet）将一个企业通信网与公共GSM网结合起来。这个系统支持“用户移动性”，用户通过使用各种类型的终端可以在服务区四处移动，并且不会与系统失去联系。“GSM on the Net”的体系结构见图1b，它由GSM和企业网组成。
All elements in the corporate network are connected to an intranet. They communicate with each other using an intranet protocol. These elements are described below. The service node enables user mobility, con­trols calls among different types of terminals, and translates addresses between the PSTN and GSM on the Net.	企业网中的所有组件都连接到内部网。它们相互之间使用一种内部网协议进行通信。下面就介绍这些组件。 “服务节点”：让用户移动性变为可能，它控制了不同终端之间的呼叫并在PSTN和“GSM on the Net”之间进行地址翻译。
The access node resembles the MSC, VLR, and BSC. GSM/BTS provides the GSM MS with wire­less access to the IP network.	“接入节点”类似于MSC、VLR和BSC。 GSM/BTS让GSM MS无线接入IP网络。
This article proposes the iGSM service, which realizes another TIPHON scenario that supports user mobility for GSM subscribers to access VoIP services. That is, a GSM subscriber ordering the iGSM service enjoys the standard GSM services when he/she is in the GSM network. When the person moves to the IP network (without a GSM mobile station), he/she can utilize an H.323 ter­minal (IP phone or PC) to receive call delivery to his/her mobile station ISDN (MSISDN) num­ber.The GSM roaming mechanism determines whether the subscriber is in the GSM or IP net­work. The iGSM solution is different from GSM on the Net in the following aspects. Unlike GSM on the Net (which integrates a corporate network with the public GSM network), iGSM is a value-added service to public GSM networks. The iGSM network does not introduce wireless access equipment (i.e., the GSM BTS) into the IP net­work, and is implemented using standard plat­forms (a general IP gateway/gatekeeper).	本文提出了iGSM这项服务，它实现了另外一种TIPHON方案，该方案支持用户移动性，GSM用户可以获得VoIP服务。也就是说，对于一个定购了iGSM业务的GSM用户来说，当他/她位于GSM网络时可以享用标准GSM服务，当他/她移到IP网络（没有GSM移动台）时可以使用H.323终端（IP电话或PC）接收传递到他/她的移动台ISDN（MSISDN）号码的呼叫传递（call delivery）。GSM漫游机制判断用户是处于GSM网络还是IP网络。iGSM解决方案在以下方面不同于“GSM on the Net”。“GSM on the Net”是将一个企业网与公共GSM网结合起来，而iGSM则是公共GSM网的一项增值服务。iGSM网络没有在IP网络中引入无线接入设备（即，GSM BTS），而是使用标准平台（普通的IP网关/网守）。