cisco english word

virtualprivate network

“VPN” redirects here.For other uses, see VPN (disambiguation).

A virtual privatenetwork (VPN) is a private communications network often used by companies ororganizations, to communicate confidentially over a public network. VPN trafficcan be carried over a public networking infrastructure (e.g. the Internet) on topof standard protocols, or over a service provider's private network with adefined Service Level Agreement (SLA) between the VPN customer and the VPNservice provider. A VPN can send data e.g. voice, data or video, or acombination of these media, across secured and encrypted private channelsbetween two points.

Authenticationmechanism

Virtual privatenetworks can be a cost effective and secure way for different corporations toprovide users access to the corporate network and for remote networks tocommunicate with each other across the Internet. VPN connections are morecost-effective than dedicated private lines; usually a VPN involves 2 parts:the protected or "inside" network, which provides physical andadministrative security to protect the transmission; and a less trustworthy,"outside" network or segment (usually through the Internet).Generally, a firewall sits between a remote user's workstation or client andthe host network or server. As the user's client establishes the communicationwith the firewall, the client may pass authentication data to an authenticationservice inside the perimeter. A known trusted person, sometimes only when usingtrusted devices, can be provided with appropriate security privileges to accessresources not available to general users.

Many VPN clientprograms can be configured to require that all IP traffic must pass through thetunnel while the VPN connection is active, for increased security. From theuser's perspective, this means that while the VPN connection is active, allaccess outside the secure network must pass through the same firewall as if theuser were physically connected to the inside of the secured network. Thisreduces the risk that an attacker might gain access to the secured network byattacking the VPN client's host machine: to other computers on the employee'shome network, or on the public internet, it is as though the machine runningthe VPN client simply does not exist. Such security is important because othercomputers local to the network on which the client computer is operating may beuntrusted or partially trusted. Even with a home network that is protected fromthe outside internet by a firewall, people who share a home may besimultaneously working for different employers over their respective VPN connectionsfrom the shared home network. Each employer would therefore want to ensuretheir proprietary data is kept secure, even if another computer in the localnetwork gets infected with malware. And if a traveling employee uses a VPNclient from a Wi-Fi access point in a public place, such security is even moreimportant. However, the use of IPX/SPX is one way users might still be able toaccess local resources.

Types of VPN

Secure VPNs usecryptographic tunneling protocols to provide the intended confidentiality(blocking snooping and thus Packet sniffing), sender authentication (blockingidentity spoofing), and message integrity (blocking message alteration) toachieve privacy. When properly chosen, implemented, and used, such techniquescan provide secure communications over unsecured networks. This has been theusually intended purpose for VPN for some years.

Because such choice,implementation, and use are not trivial, there are many insecure VPN schemesavailable on the market.

Secure VPNtechnologies may also be used to enhance security as a "securityoverlay" within dedicated networking infrastructures.

Secure VPN protocolsinclude the following:

IPsec(IP security) - commonly used over IPv4, and an obligatory part of IPv6.

SSL/TLSused either for tunneling the entire network stack, as in the OpenVPN project,or for securing what is, essentially, a web proxy. SSL is a framework moreoften associated with e-commerce, but it has been built-upon by vendors likeAventail and Juniper to provide remote access VPN capabilities. A majorpractical advantage of an SSL-based VPN is that it can be accessed from anypublic wireless access point that allows access to SSL-based e-commercewebsites, whereas other VPN protocols may not work from such public accesspoints.

OpenVPN,an open standard VPN. Clients and servers are available for all major operatingsystems.

PPTP(Point-to-Point Tunneling Protocol), developed jointly by a number ofcompanies, including Microsoft.

L2TP(Layer 2 Tunneling Protocol), which includes work by both Microsoft and Cisco.

L2TPv3(Layer 2 Tunneling Protocol version 3), a new release.

VPNQuarantine The client machine at the end of a VPN could be a threat and asource of attack; this has no connection with VPN design and is usually left tosystem administration efforts. There are solutions that provide VPN Quarantineservices which run end point checks on the remote client while the client iskept in a quarantine zone until healthy. Microsoft ISA Server 2004/2006together with VPN-Q 2006 from Winfrasoft or an application called QSS(Quarantine Security Suite) provide this functionality.

MPVPN(Multi Path Virtual Private Network). MPVPN is a registered trademark owned byRagula Systems Development Company. See Trademark Applications andRegistrations Retrieval (TARR)

Some large ISPs nowoffer "managed" VPN service for business customers who want thesecurity and convenience of a VPN but prefer not to undertake administering aVPN server themselves. In addition to providing remote workers with secureaccess to their employer's internal network, other security and managementservices are sometimes included as part of the package. Examples includekeeping anti-virus and anti-spyware programs updated on each client's computer.

Trusted VPNs do notuse cryptographic tunneling, and instead rely on the security of a singleprovider's network to protect the traffic. In a sense, these are an elaborationof traditional network and system administration work.

Multi-ProtocolLabel Switching (MPLS) is often used to build trusted VPN.

L2F(Layer 2 Forwarding), developed by Cisco, can also be used.

Characteristics inapplication

A well-designed VPNcan provide great benefits for an organization. It can:

Extendgeographic connectivity.

Improvesecurity where data lines have not been ciphered.

Reduceoperational costs versus traditional WAN.

Reducetransit time and transportation costs for remote users.

Simplifynetwork topology in certain scenarios.

Provideglobal networking opportunities.

Providetelecommuter support.

Providebroadband networking compatibility.

Providefaster ROI (return on investment) than traditional carrier leased/owned WANlines.

Showa good economy of scale.

Scalewell, when used with a public key infrastructure.

However, since VPNsextend the "mother network" by such an extent (almost every employee)and with such ease (no dedicated lines to rent/hire), there are certainsecurity implications that must receive special attention:

Securityon the client side must be tightened and enforced, lest security be lost at anyof a multitude of machines and devices. This has been termed Central ClientAdministration, and Security Policy Enforcement. It is common for a company torequire that each employee wishing to use their VPN outside company offices(eg, from home) first install an approved firewall (often hardware). Someorganizations with especially sensitive data, such as healthcare companies,even arrange for an employee's home to have two separate WAN connections: onefor working on that employer's sensitive data and one for all other uses.

Thescale of access to the target network may have to be limited.

Loggingpolicies must be evaluated and in most cases revised.

A single breach orfailure can result in the privacy and security of the network beingcompromised. In situations in which a company or individual has legalobligations to keep information confidential, there may be legal problems, evencriminal ones, as a result. Two examples are the HIPAA regulations in the U.S.with regard to health data, and the more general European Union data privacyregulations which apply to even marketing and billing information and extend tothose who share that data elsewhere.

One way to reduce theconsequences from a lost or stolen laptop is to use one of the Thin clientlaptops now sold by several companies. These can allow mobile workers to accesssecurity-sensitive databases with less risk of lost or compromised data shouldthe laptop be lost or stolen since it has no local storage.

Tunneling

Tunneling is thetransmission of data through a public network in such a way that routing nodesin the public network are unaware that the transmission is part of a privatenetwork. Tunneling is generally donedata and protocol information within thepublic network protocol data so that the tunneled data is not available toanyone examining the transmitted data frames. Tunneling allows the use ofpublic networks (eg, the Internet), to carry data on behalf of users as thoughthey had access to a 'private network', hence the name.

Port forwarding isone aspect of tunneling in particular circumstances.

VPN security dialogs

The most importantpart of a VPN solution is security. The very nature of VPNs — putting privatedata on public networks — raises concerns about potential threats to that dataand the impact of data loss. A Virtual Private Network must address all types ofsecurity threats by providing security services in the areas of:

Authentication(access control) - Authentication is the process of ensuring that a user orsystem is who the user claims to be. There are many types of authenticationmechanisms, but they all use one or more of the following approaches:

somethingyou know (eg, a login name, a password, a PIN)

somethingyou have (eg, a computer readable token (eg, a Smart card), a card key)

somethingyou are (eg, fingerprint, retinal pattern, iris pattern, hand configuration,etc)

What is generallyregarded as weak authentication makes use of one of these components, usually alogin name/password sequence. Strong authentication is usually taken to combineat least two authentication components from different areas (i.e., two-factorauthentication). But note that use of weak and strong in this context can bemisleading. A stolen smart card and a shoulder-surfed login name / PIN sequenceis not hard to achieve and will pass a strong authentication two-factor testhandily. More seriously, stolen or lost security data (eg, on a backup tape, alaptop, or stolen by an employee) dangerously furthers many such attacks onmost authentication schemes. There is no fully adequate technique for theauthentication problem, including biometric ones.

----------------------

spoken english英语口语

wehave a week of testing period. 我们有一个星期的测试期。

wehave a week of testing time. 我们有一个星期的测试时间。

weimplement way is to use a special line to Hong Kong. 我们实现的方式是使用专线到香港。

dedicated专有的

dedicated line 专用线路

weprovide a router in the network of your company. 我们提供一台路由器放在你们公司的网络。

use this router to establish VPN with our data center room. 使用这个路由器去和我们数据中心机房建立VPN。

website 网站

domestic 国内的

ourrouter to achieve domestic website out from telecom. 我们路由器实现国内网站从电信出去。

solution 解决方案plan 方案

colleague 同事

---------------------------------------------------------------------

spoken english英语口语

wehave a week of testing period. 我们有一个星期的测试期。

wehave a week of testing time. 我们有一个星期的测试时间。

weimplement way is to use a special line to Hong Kong. 我们实现的方式是使用专线到香港。

dedicated专有的

dedicated line 专用线路

weprovide a router in the network of your company. 我们提供一台路由器放在你们公司的网络。

use this router to establish VPN with our data center room. 使用这个路由器去和我们数据中心机房建立VPN。

dedicated privatelines

专有的线路

---------------------------------

在中国需要用vpn才能使用facebook英语如下：

People need VPN touse facebook in China

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(LISP) Locator ID Separation Protocol
定位器ID分离协议
(PIC) Prefix-Independent Convergence
(TCAM)三态内容寻址存储器(Ternary Content Addressable Memory)
accurate 精确的，正确的，
achieve 实现，获得，取得，
across 穿过，
administrative 管理的，
advertise 通告，通知，
announcement 宣告，通告，
applet 支程序，小程序，上下文，
apportioned 分配，分派，
assignment 分配，任务，
associated 关联的，联合的，联系，
asymmetric 不对称的，非对称的，
attached 附加的，
attribute 属性，特征，
automatic 自动的，必然的，
automatically 自动的，
available 可用的，
avoid 避免，避开，
black hole 黑洞
block 阻止，
blocking 阻塞，
boundary 边界，
carry 运载，
chassis 机架
circuit 电路，
Cisco BFD Bidirectional Forwarding Detection (BFD) 是一种双向转发检测机制，可以提供毫秒级的检测，可以实现链路的快速检测，BFD通过与上层路由协议联动，可以实现路由的快速收敛，确保业务的永续性。
classification 分类，
communication 通信，通讯
compare 比较，
compatibility 兼容性，
compiled 编译，
component 组成的，构成的，成分，
confederation 联盟
confederation 联盟，
confirm 确认，
connectivity 连通性，
consideration 考虑，原因，关心，
Control Plane Policing (CoPP)被称为控制面板策略

controller 控制器，管理员，
convergence 收敛，汇聚，

corrective 矫正的，纠正的，
correctly 正确的，得体地，
corresponding 类似的，对应的，符合的，
counter 计时器，计数器
credential 证书，凭证，凭据，
CSNP，Complete sequence number PDU，用于发布完整链路状态数据库
currently 当前，现在
cycles 周期，
decremented 减缩
degree 程度，等级，
demand 按需，需求，
dependent 依靠的，
designated 指定的，
destine 注定，命定，
destined 注定的，命定的，
diagnostic 诊断，调试，
directed 定向的，指导，
directed 指向，定向的，
dispute 阻止，抗拒，
distribute 分配，分发，
dominance 优势，
driven 驱使，
dual tier 双层
dual 双重的，双数的，
DUID DUID(DHCP Unique Identifier,DHCP 唯一标识符)是唯一标识一台 DHCPv6 设备(包括客户端、中继和服务器) 的标识符,
duration 持续，
ECMP （Equal Cost Multi-path Routing）
effect 影响，效果，
egress 出口，外出，
Embedded Event Manager (EEM) 嵌入式事件管理器，能够实现进程级的自动策略控制。
embedded 嵌入式的，内含的，
enable 使能够，
endpoint 端点，终点，终端
enhancement 增强，增加
EPL通常用于以太网业务点到点透明传输。
EPL（Ethernet Private Line）就是以太网专线业务，以太网专线接入业务也可理解为透传，
even if 即使，虽然，
event 事件，大事，结果，
exactly 正确的，确切的，
excessive 过多的，极度的，过分的，
excessive 过多的，过分的，极度的，
exit 出口，退出，离去，
experiencing 体验，经历，
expired 过期，
expose 显示，揭露，
extended 延伸的，扩大的，
external 外部的，
facilitate 帮助，促进，
factor 因素，要素，
failure 故障，失败，
field 领域，
flap 翻动，
forum 论坛，讨论会，
gather 收集，收割，
glean 收集，
gracefully 优雅的，优美的，
guard 防护，
horizon 水平线，地平线，
identical 同一的，相同的，
identify 识别，确定，鉴别，
identity 标示，
implicit 隐式的，
improvement 改进，改善，
independent 独立的，单独的，
independently 独立地，自立地。
indicate 表明，指出，
indication 指示，指出，回应，确认，
individual 个人，单个，单独的，
influence 影响，改变，
influence 影响，改变，
instance 实例，情况，建议，
instead 代替，
interference 干扰，冲突，
intermittent 间歇的，段续的，
issues 问题，
larger 大的，
LLDP （Link Layer Discovery Protocol）链路层发现协议
logical 逻辑的
magnitude (time) 大小，量级，
maintain 维持，保持，
mean 平均的，平均值，
measure 测量，措施，
mechanism 机制，
mechanism 机制，原理，途径，
MED（multi-exit discriminator）多出口鉴别器，辨别者，
method 方法
method 方法，办法，
metro-Ethernet 城域以太网
migrate 迁移，移动，
mitigate 减轻，
MLD = Multicast Listener Discover ，组播侦听发现协议，是组播技术中使用的一种网络协议
它用于IPv6路由器在其直连网段上发现组播侦听者。组播侦听者（Multicast Listener）是那些希望接收组播数据的主机节点。
MLD使用ICMPv6（Internet Control Message Protocol for IPv6，针对IPv6的互联网控制报文协议）报文类型。所有的MLD报文被限制在本地链路上，跳数为1。
MOS——Mean Opinion Score 平均意见值
multiple 倍数，多重的，许多的，
mutual 相互的，彼此的，
narrow 狭窄的，度量小的，
nonidentical 不全同的，非同一的
notify 通告，告知，
observes 观察，
occur 发生，出现
occurring 发生，
offer 提供，
offer 提供，提议。
opinion 意见，
opposed 相对，
ORF：Outbound Route Filtering
original 原有的，原始的，
otherwise 否则，列外，
Over the ToP (OTP)
overall 全部的，全体的，
overflow 溢出，
override 重载，
overview 概况，概览。
particular 特别的，详细的，
perform 执行，完成，
Performance Routing (PfR) 性能路由
performance 性能，执行。
periodically 定期的，周期性的，
permanent 永久的，永恒的，
picosecond 皮秒；微微秒；万亿分之一秒
piece 块，件，
PMTUD PathMTUDiscovery 路径最大传输单元发现
preferred 优先的，首选的，
preferred 优先的，首选的，
present 提出，介绍，
preserve 保存，保持，维持
preserved 保存，保藏的，
prevent 阻止，防止
prevent 阻止
prevent 阻止，防止，
prevent 阻止，预防，
primary 主要的，
privacy 私密，隐私，
private 私有的，私人的，
promiscuous 杂合的，混杂的，
protected 保护的端口
purpose 目的，用途，意图，
query 查询，
query 查询，
receipt 收到，收入
recognize 识别，认出，
recurring 经常的，反复的，
redirect 重定向，
redistribution 从新分配
redundancy 冗余，
redundancy 冗余，
refresh 更新，刷新，
region 区域，地区
relay 传播，接替，
relayed 转播，转发，
rendezvous 回合，集合点，
replicate 复制的，
report 报告，
reported 报告的，
reported 报告，记录，
require 需要，要求，
reside on 属于，位于，
resolution 解析，
resolve 解决，解析，
response 响应，回应，
restriction 限制，约束，
restriction 限制，约束，
result 结果，导致，产生。
retransmit 重传，重新发送
reverse 反向，相反，
revision 修正，
risk 风险，危险，冒险。
RRP （角色决定协议）
score 分数，值。
script 脚本，
segment 分段
separate 分开的，分离的。
short-duration 短历时，
shorten 缩短，减少，变短，
significant 重大的，有效的，
significantly 显著的，
solicitation 请求，
sparse 稀疏的，稀少的，
split 分割
split 分离，分割，
SRTT(Smooth round-trip time)顺利往返时间：一个EIGRP报文发送给邻居然后到本地路由器从邻居处接收到确认报文所花费的时间，单位是ms。
standardized 标准的，标准化的，
store 存储，
stuck 卡，卡住，
suboptimal 次最优的，
suboptimal 次最优的，次优的，
subscriber 用户，订户，
suffer 蒙受
suffering 蒙受
swapped 交换的，
take effect 生效，起作用，
take up 占据，占去，拿起，开始从事，
threshold 阀值，门槛，阀，
throttling 限流，限制，
throughput 吞吐量，吞吐率，
tier 层，排，列，等级
totally stubby 完全末节区域，完全末梢区域，
transmitting 传送，传递，
transparency 透明，透明度，
transparency 透明，透明度
transport 运输，
underperform 表现不佳，工作不如预期
unidirectional 单向的，单向性的，
unique 唯一的，独特的，
uRPF（Unicast Reverse Path Forwarding）是一种单播反向路由查找技术，用于防止基于源地址欺骗的网络攻击行为。
utilize 利用，运用。
validity 有效性，正确性，
variance 方差，变异数
vector 矢量，向量
verified 查证，已验证，
verify 验证，
visible 明显的，现有的，可见的，
VPLS（Virtual Private Lan Service）虚拟专用局域网业务
VSS（virtual switch system）虚拟交换系统
wide 广泛的，宽的，

without 没有，

Quality of Service （QoS）

quality 质量

critical 关键
mission-critical 关键任务

methods for implementing QoS policy

CLI
MQC
AutoQoS VoIP (voice QoS)
AutoQoS Enterprise (voice,video,and data QoS)

QPM (QoS Policy Manager)

wizard 向导

Three Models for Quality of Service

Best-Effort
IntServ
DiffServ

RSVP (Resource Reservation Protocol)

drawback 缺点

differentiated 区分，差分

DSCP（Differentiated Services Code Point）

encode 编码
decode 解码

Per-Hop Behaviors

EF (Expedited Forwarding ) 加速转发
AF （Assured Forward ）

assure 确保，保证，担保

Class-Selector (IP Precedence) PHB

baseline 基线，底线

realtime 即时，实时

transactional 交互式

recognition 识别

queuing 队列排队

congestion 拥塞

aggregation 聚集

choke 拥塞堵塞窒息

choke point 瓶颈堵塞点

algorithms 算法
----------------------------------------------------------------------------------------------------
dispatch 调度，派遣

starve 饿死

round robin 轮转 lun zhuan

weighted 加权加权的

deficit 赤字缺乏逆差

components 组件

scheduler 调度程序

fair 公平的

deprecated 过时的

versatile 多才多艺的，多用途的，通用的，

prevented 预防

Random Early Detection

Weighted Random Early Detection

threshold 阀值

policing 流量监管，策略，监管，管制

shaping 整形，休整，

sufficient 足够的，

available 可获得的

conform 符合

exceed 超过

violate 违反

CIR = committed information rate (bps)
PIR = peak information rate (bps)

peak 最大值的，最高的，

Explicit 明确，
backward 向后的，
congestion 拥塞

FECN -- Forward Explicit Congestion Notification

BECN -- Backward Explicit Congestion Notification

Efficiency 效率

mechanisms 机制

throughput 吞吐量

throughout 直始至终，始终

overhead 开销

serialization 串行化，系列化，

jitter 抖动

variable 变化的，可变的，变量

LFI = Link Fragmentation and Interleaving

campus 园区，校区，校园，

implementing 实施

drawback 缺点

mechanism 机制

metering 测量，测定，计量

enforce 执行，实施，

Explicit congestion notification (ECN)

explicit 显示，明确的，

capable 有才能的，能干的，
transport 传输，运输，

provisioning 配置，供应，

SRR Shaped Round Robin

threshold 阀值

colleague 同事

Characteristic 特征，特性，特色

Scope 范围

EVPL Ethernet Virtual Private Line 就是以太网虚拟专线业务

EPL Ethernet Private Line 以太网专线

SDH Synchronous Digital Hierarchy 同步数字体系

注意：SDH是一种物理传输方式、 IP网络是一种网络连接模式、 IP ON SDH 即POS是让IP在SDH的网上跑，这三者的概念要分清。

MSTP是SDH为了适应传输以太网数据而在SDH基础上改进后的传送平台标准，主要改进是在接口单元增加了ETH/ATM等业务单元，基础传送层主要还是沿用SDH传输；MSTP（Multi-Service Transfer Platform）（多业务传输平台）是从SDH 平台延伸出来的同时实现TDM、ATM、以太网等业务的接入、处理和传送，提供统一网管的业务平台体系。

IPLC是"International Private Leased Circuit" 的缩写，即“国际专线”，是指用户专用的跨国的数据、话音等综合信息业务的通信线路。通俗地说，也就是指传统的专线，如DDN、E1等，用于互连两点之间的通信，只不过IPLC是跨国跨境的而已。

UNI User Network Interface 用户网络接口

接入网是由业务节点接口SNI （Service Node Interface）和用户网络接口UNI（User Network Interface）之间的一系列传送实体组成。为传送数据业务提供所需传送承受能力的实施系统，它可以通过 Q3 接口进行配置和管理

architecture 架构

VPLS Virtual Private Lan Service 虚拟专用局域网业务

replicate 复制

EVC Ethernet virtual Circuit 以太网虚链路

Appear 出现

Unique 独一无二的唯一的

Diverse 不同的，

Feasible 可行的，可能的，

speed up 加速

Convergence 收敛，

Alternative 备选

loop-free 无回路的

Snooping 窥探

Poisoning 中毒，毒害

VPLS 虚拟专用局域网业务（Virtual Private Lan Service）

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