Meru Networks

SBC的历史表明，有几家公司参与了为运营商和企业创建和推广SBC细分市场。最初的面向运营商的SBC公司（或者是因为已经收购或已经解散了几家）：Acme Packet（由Oracle Corporation于2013年收购），Cisco Systems，Kagoor Networks（2005年被Juniper Networks收购，提供路由器 - 集成解决方案），Jasomi Networks（由Ditech Communications于2005年收购，现称为Ditech Networks），Netrake（2006年由Audiocodes收购[5]），Newport Networks（现已停业），NexTone（首次与Reef Point合并至形成Nextpoint，后来被Genband收购），Aravox（2003年被阿尔卡特收购并终止）和Emergent Network Solutions（2006年被Stratus Technologies收购，2009年被分拆为Stratus Telecommunications），Sonus Networks，Patton Electronics，Veraz Networks合并2010年，Dialogic与Dialogic公司，Cirpack，Data Connection于2009年更名为Metaswitch，以及Nable Communications。根据RFC 3261（SIP）和许多其他相关RFC的作者Jonathan Rosenberg的说法，Dynamicsoft实际上与Aravox一起开发了第一个工作SBC，但该产品从未真正获得市场份额。。 2004年5月，纽波特网络首次在伦敦证券交易所的AIM上市（NNG），而思科自1990年以来一直在公开上市.Acme Packet于2006年10月在纳斯达克上市。随着收购范围的缩小，NexTone与Reefpoint合并成为Nextpoint，后来由Genband于2008年收购。与此同时，出现了“集成”SBC，其中边界控制功能被集成到另一个边缘设备中。根据Infonetics Research，思科的CUBE（思科统一边界元素）企业和Oracle ACME都是市场上领先的企业SBC。随着2017年10月30日GENBAND和Sonus合并创建Ribbon Communications，SBC市场继续巩固 。

VoIP网络的持续增长将SBC进一步推向了边缘，要求在容量和复杂性方面进行适应。随着VoIP网络的增长和流量的增加，越来越多的会话正在通过SBC设备。供应商正以各种方式满足这些新的规模要求。有些人开发了独立的负载平衡系统，可以坐在SBC集群前面。其他人使用最新一代芯片组开发了新的架构，使用服务卡提供更高性能的SBC和可扩展性。2100433B

前言

Chapter 1 Hydrometric Stations

1.1 Hydrometric network design

1.1.1 Purpose of network design and classification of network

1.1.2 Principles for designing a base network

1.1.3 Hydrometric networks in some countries

1.2 Selection and reconnaissance of river reaches for hydrometric stations

1.2.1 Contr01 0f hydrometric stations

1.2.2 Selection of stream gauging reaches

1.2.3 Survey for the stream-gauging reaches

1 3 Establishment of hydrometric stations

1.3.1 Procedures of establishing gauging stations and stream gauging stations

1.3.2 Establishment of the cross section and the base line

Chapter 2 Water Level

2.1 0utline

2.1.1 The base level

2.1.2 Water level Or stage

2.2 Instruments for observing stages

2.2.1 Different types of gauges

2.2.2 Automatic recording systems

2.2.3 Stilling well

2.2.4 Accuracy of water level measurements

2.2.5 Presentation of results of water level measurements

2.2.6 International Standards

2.3 Processing of stage records

2.3.1 Checking the datum level and zero point of the gauge

2.3.2 Computation of mean daily stage

2.3.3 Interpolation of stage records

2.3.4 Plotting stage hydrographs

2.3.5 Making average daily hydrograph tables

2.3.6 Selection of stages for various durations

2.3.7 Inspecting the rationality of stage data

3. 1 Introduction

3.1.1 Purpose

3.1.2 Different methods of discharge measurements

3, 2 Measurement of cross Section

3.2.1 Introduction

3.2.2 Measurement of depth

3.2.3 Position of verticals

3.2.4 Data processing and computation

3.2.5 International standards

3.3 Velocity of flow

3.3.1 Pulsation of the velocity

3.3.2 Velocity distribution

3.3.3 Current meter

3.4 Current meter measurement and discharge computation

3.4.1 Theory

3.4.2 Arrangement of verticals and points for velocity measurement

3.4.3 Duration of measurement

3.4.4 Computation of discharge

3.5 Measurement of discharge by float method

3.5.1 Principle and method of measuring stream flow by a float

3.5.2 Float coefficient

3.5.3 Computation of discharge for surface float method

3.5.4 Computation of discharge from mean velocity by float method

3.5.5 Example of a subsurface float

3.6 Other methods of flow measurement

3.6.1 Dilution (tracer) method of flow measurement

3.6.2 Flow measuring structures

3.6.3 Measurement of discharge by ultrasonic wave method

3.6.4 Electromagnetic method

3.6.5 Flow measurement in hydroelectric station

3.6.6 Limited number of verticals (the h3/2 method)

3.6.7 Moving boat method

3.6.8 Slope area method

3.6.9 The Acoustic Doppler Current Profiler. ADCP

3.6.10 Remarks

3.7 Errors in measurement and computation of discharge

3.7.1 Errors in measuring discharge

3.7.2 Computational error of discharge

3.7.3 Analysis and estimation of the composite error

3.7.4 Error due to reduction

3.7.5 Accuracy of discharge measurements by velocity——area methods

3.7.6 Selection of methods

Chapter 3 Discharge Measurement

Chapter 4 Compilation of Stream Flow Data

Chapter 5 Sediment Observation and Sediment Data Compilation

Chapter 6 Groundwater Monitoring

Chapter 7 Collection of Water Quality Information

REVIEW AND QUESTION

参考文献

附录2100433B

VPN Routing and Forwarding (VRF) is a technology used in computer networks that allows multiple instances of a routing table to co-exist within the same router at the same time. Because the routing instances are independent,the same or overlapping IP addresses can be used without conflicting with each other.

VRF---VPN路由转发实例（VPN Routing & Forwarding Instance）

每一个VRF可以看作虚拟的路由器，好像是一台专用的PE设备。该虚拟路由器包括如下元素：

一张独立的路由表，当然也包括了独立的地址空间；

一组归属于这个VRF的接口的集合；

一组只用于本VRF的路由协议。

对于每个PE，可以维护一个或多个VRF，同时维护一个公网的路由表（也叫全局路由表），多个VRF实例相互分离独立。