Comparative Study of Virtual Private Network and Leased Line

8/3/2019 Comparative Study of Virtual Private Network and Leased Line

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Comparative Study of

Leased Line and Virtual Private

Network

Student Names: Student Numbers:

Cyprene Paguerao 0515-0410-0527

Sunshine Carpio 0515-0610-0677

Subject Code: Subject Name:

I.T. 409 Networks and the Internet

Center Code: Country:

0515 Philippines


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Table of ContentsI. Introduction ........................................................................................................ 4

II. Objectives .......................................................................................................... 5

III. History and Current Technology ......................................................................... 6

A. History ............................................................................................................ 6

B. Current ............................................................................................................ 7

IV. Protocols and Network Configuration ................................................................. 8

A. Protocols ......................................................................................................... 8

B. Network Topology ......................................................................................... 10

C. Network Architecture ..................................................................................... 12

D. Network Algorithm......................................................................................... 13

V. Technical Content ............................................................................................ 19

A. Hardware Requirements ............................................................................... 19

B. Software Requirements ................................................................................ 21

C. Application Area ............................................................................................ 22D. Security ......................................................................................................... 24

VI. Implementation ................................................................................................. 26

A. Cost and Benefit Analysis ............................................................................. 26

B. Strength and Weakness ................................................................................ 27

C. Future Development ..................................................................................... 30

D. Summary/Conclusion .................................................................................... 31

VII. References/Bibliography ............................................................................... 32


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I. IntroductionVPN

A VPN supplies network connectivity over a possibly longphysical distance. In this respect, a VPN is a form of WAN. The key

feature of a VPN, however, is its ability to use public networks like theInternet rather than rely on private leased lines. VPN technologiesimplement restricted-access networks that utilize the same cabling androuters as a public network, and they do so without sacrificing featuresor basic security. A virtual private network (VPN) is a network that usesa public telecommunication infrastructure, such as the Internet, toprovide remote offices or individual users with secure access to theirorganization's network. A virtual private network can be contrasted withan expensive system of owned or leased lines that can only be used byone organization. The goal of a VPN is to provide the organization with

the same capabilities, but at a much lower cost. A VPN works by usingthe shared public infrastructure while maintaining privacy throughsecurity procedures and tunneling protocols such as the Layer TwoTunneling Protocol (L2TP). In effect, the protocols, by encrypting dataat the sending end and decrypting it at the receiving end, send the datathrough a "tunnel" that cannot be "entered" by data that is not properlyencrypted. An additional level of security involves encrypting not onlythe data, but also the originating and receiving network addresses.

Leased Line

A leased line connects two locations for private voice and/ordata telecommunication service. Not a dedicated cable, a leased line is

actually a reserved circuit between two points. Leased lines can span

short or long distances. They maintain a single open circuit at all times,

as opposed to traditional telephone services that reuse the same lines

for many different conversations through a process called "switching."A

leased line, a type of dedicated line, is a permanent fiber optic or

telephone line connection between two points set up by a

telecommunications carrier. It can be used for telephone, data, or

Internet services. Often, businesses will use a leased line to connectgeographically distant offices because it guarantees bandwidth for

network traffic. For example, a bank may use a leased line in order to

easily transfer financial information from one branch office to another.

Both long and short distances can be spanned by a leased line, and

customers generally pay a flat monthly rate for the service. Before

broadband Internet access was readily available, a company's cost

was charged according to the distance between the two points. More

recently, leased line replacement services allow a user to upgrade and

improve the lines with fees that are per-end only.
http://searchenterprisewan.techtarget.com/definition/tunnelinghttp://searchnetworking.techtarget.com/definition/protocolhttp://searchenterprisewan.techtarget.com/definition/Layer-Two-Tunneling-Protocolhttp://searchenterprisewan.techtarget.com/definition/Layer-Two-Tunneling-Protocolhttp://searchnetworking.techtarget.com/definition/protocolhttp://searchenterprisewan.techtarget.com/definition/tunneling


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II. Objectives

To know the difference of the two technologies, the Virtual Private Network

and the Leased Line.

To know the advantage and disadvantage of each technology

To know the uses of the technologies


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III. History and Current Technology

A. History

Leased Line

Leased lines services (or private line services) became digital in the1970s with the conversion of the Bell backbone network from analog todigital circuits. This conversion allowed AT & T to offer Data phone DigitalServices (later re-branded digital data services) that started thedeployment of ISDN and T1 lines to customer premises to connect.Leased lines were used to connect mainframe computers with terminalsand remote sites, via IBM Systems Network Architecture (created in 1974)or DEC net (created in 1975).With the extension of digital services in the1980s leased lines were used to connect customer premises to FrameRelay or ATM networks. Access data rates increased from the original T1option up to T3 circuits. In the 1990s with the advances of the Internet,leased lines were also used to connect customer premises to ISP Point ofPresence's whilst the following decade saw a convergence of the aforementioned services (frame relay, ATM, Internet for businesses) with theMPLS integrated offerings. Access data rates also evolved dramatically tospeeds of up to 10 GB/s in the early 21st century with the Internet boomand increased offering in long-haul optical networks or Metropolitan AreaNetworks.

VPNThe term VPN has been associated in the past with such remoteconnectivity services as the public telephone network and Frame RelayPVCs, but has finally settled in as being synonymous with IP-based datanetworking. Before this concept surfaced, large corporations hadexpended considerable resources to set up complex private networks, nowcommonly called Intranets. These networks were installed using costlyleased line services, Frame Relay, and ATM to incorporate remote users.For the smaller sites and mobile workers on the remote end, companiessupplemented their networks with remote access servers or ISDN. At thesame time, the small- to medium-sized enterprises (SMEs), who could not

afford dedicated leased lines, were relegated to low-speed switchedservices. As the Internet became more and more accessible andbandwidth capacities grew, companies began to offload their Intranets tothe web and create what are now known as Extranets to link internal andexternal users. However, as cost-effective and quick-to deploy as theInternet is, there is one fundamental problemsecurity.
http://www.enotes.com/topic/Backbone_networkhttp://www.enotes.com/topic/ISDNhttp://www.enotes.com/topic/Digital_Signal_1http://www.enotes.com/topic/Mainframe_computerhttp://www.enotes.com/topic/IBM_Systems_Network_Architecturehttp://www.enotes.com/topic/DECnethttp://www.enotes.com/topic/Frame_Relayhttp://www.enotes.com/topic/Frame_Relayhttp://www.enotes.com/topic/Asynchronous_Transfer_Modehttp://www.enotes.com/topic/Internet_service_providerhttp://www.enotes.com/topic/Point_of_Presencehttp://www.enotes.com/topic/Point_of_Presencehttp://www.enotes.com/topic/MPLShttp://www.enotes.com/topic/Internet_boomhttp://www.enotes.com/topic/Metropolitan_Area_Networkhttp://www.enotes.com/topic/Metropolitan_Area_Networkhttp://www.enotes.com/topic/Metropolitan_Area_Networkhttp://www.enotes.com/topic/Metropolitan_Area_Networkhttp://www.enotes.com/topic/Internet_boomhttp://www.enotes.com/topic/MPLShttp://www.enotes.com/topic/Point_of_Presencehttp://www.enotes.com/topic/Point_of_Presencehttp://www.enotes.com/topic/Internet_service_providerhttp://www.enotes.com/topic/Asynchronous_Transfer_Modehttp://www.enotes.com/topic/Frame_Relayhttp://www.enotes.com/topic/Frame_Relayhttp://www.enotes.com/topic/DECnethttp://www.enotes.com/topic/IBM_Systems_Network_Architecturehttp://www.enotes.com/topic/Mainframe_computerhttp://www.enotes.com/topic/Digital_Signal_1http://www.enotes.com/topic/ISDNhttp://www.enotes.com/topic/Backbone_network


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B. Current

Leased Line

Leased lines are stated to be more suited for businesses that conductbusiness online and demand fast and reliable access and zero downtime.

Internet leased lines differ from point to point lines in the respect they connect

a site to the internet, whereas a point to point leased line will connect 2 sites,

without internet access. Businesses can interconnect separate offices and

buildings using a leased line which ensures that users are able to connect fast

and directly to their host server or the internet anytime they want. Businesses

need not have to own or deploy the connections as they can lease them from

service providers. Leased lines can transfer data rates at speeds ranging from

1.5 Mbps (E1 connections) to 34.36 Mbps (E3 connections).The high cost ofleased lines occurs due to their installation lead-in times, cost of installation

and the maintenance and access fees which often make them unaffordable to

small businesses.

VPN

Todays VPN solutions overcome the security factor. Using specialtunneling protocols and complex encryption procedures, data integrity andprivacy is achieved in what seems, for the most part, like a dedicatedpoint-to-point connection. And, because these operations occur over a

public network, VPNs can cost significantly less to implement thanprivately owned or leased services. Although early VPNs requiredextensive expertise to implement, the technology has matured already to alevel that makes its deployment a simple and affordable solution forbusinesses of all sizes, including SMEs who were previously being left outof the e-revolution. Using the Internet, companies can connect theirremote branch offices, project teams, business partners, and e-customersinto the main corporate network. Mobile workers and telecommuters canget secure connectivity by dialing into the POP (Point-of-Presence) of alocal ISP (Internet Service Provider). With a VPN, corporations seeimmediate cost reduction opportunities in their long distance charges(especially important to global companies), leased line fees, equipmentinventories (like large banks of modems), and network supportrequirements.
http://connectivity.onestopclick.com/rfq/8/leased-line.htmhttp://connectivity.onestopclick.com/rfq/7/point-to-point.htmhttp://connectivity.onestopclick.com/rfq/7/point-to-point.htmhttp://connectivity.onestopclick.com/rfq/8/leased-line.htm


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IV. Protocols and Network Configuration

A. Protocols

Leased Line

Leased Line Support

- All IP Office systems are capable of connecting to leased lineservices. Six physical types of Leased Line are supported, X.21, V.35and V.24, via the WAN port, or E1/T1 and Basic Rate via the trunkinterfaces on the base unit. The X.21, V35 and V24 are externallyclocked and can operate at any speed up to and including 2M. E1/T1trunks can be configured to operate in a fractional mode for 'point tomulti-point' applications i.e. a single 2M interface could be treated as 3x 512K and 8 x 64K going to 11 different locations. When using T1 as a

Leased Line it is possible to use the same circuit for switched circuitservices. Not all types of leased line are available in all territories,check for availability.

Dial-Up Circuit Support

- Where the amount of traffic does not justify the cost of adedicated leased line, the system can provide data connectivity viaISDN dial-up circuits using its E1/T1 or Basic Rate trunks. Where dataspeeds greater than a single channel are required (64K/56K),additional channels can be added to the call as and when they areneeded.

Point-to-Point Protocol (PPP)

- PPP is an industry standard Wide Area Networking Protocol,that allows inter-working with a wide range of 3rd party routers. PPP isused over dial-up or leased line circuits where a single channel is usedto connect the two locations together

Multi-Link Point-to-Point Protocol (ML-PPP)- IP Office supports Multi-Link PPP allowing additional calls to

be made where bandwidth greater than a single channel is required.The maximum number of channels available to data can be set on aservice-by-service basis. When the available bandwidth reaches a userdefined limit additional channels can be automatically added. Similarly,

when traffic falls then the number of channels in use can beautomatically reduced. If there is no data traffic on any of the channelsin use then all lines can be cleared. Since most carriers have aminimum charge for calls, the period that a channel has to be idlebefore clearing is configurable. Through these mechanisms call costscan be effectively controlled while ensuring that bandwidth is availableas and when it is needed.

VPN

PPTP (Point-to-Point Tunneling Protocol)


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- Its the most widely supported VPN method among Windows

users and it was created by Microsoft in association with other

technology companies. The disadvantage of PPTP is that it does not

provide encryption and it relies on the PPP (Point-to-Point Protocol)

protocol to implement security measures. But compared to othermethods, PPTP is faster and it is also available for Linux and Mac

users.

L2TP (Layer 2 Tunneling Protocol)

- Its another tunneling protocol that supports VPNs. Like PPTP,

L2TP does not provide encryption and it relies on PPP protocol to do

this. The difference between PPTP and L2TP is that the second one

provides not only data confidentiality but also data integrity. L2TP was

developed by Microsoft and Cisco as a combination between PPTP

and L2F (Layer 2 Forwarding).

IPsec protocol

- Can be used for encryption in correlation with L2TP tunneling

protocol. It is used as a protocol suite for securing Internet Protocol

(IP) communications by authenticating and encrypting each IP packet

of a data stream. IPsec requires expensive, time consuming client

installations and this can be considered an important disadvantage.

SSL (Secure Socket Layer)

- Is a VPN accessible via https over web browser. The advantage of

this SSL VPN is that it doesnt need any software installed because it

uses the web browser as the client application. Through SSL VPNs theusers access can be restrict to specific applications instead of allowing

access to the whole network.


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B. Network Topology

Leased Line

a) Hub-and-spoke Topology

The most commonly encountered topology is a hub-and-spoke

topology, where a number of remote offices (spokes) are connected to acentral site (hub). The remote offices usually can exchange data (there areno explicit security restrictions on inter-office traffic), but the amount ofdata exchanged between them is negligible. The hub-and-spoke topologyis used typically in organizations with strict hierarchical structures, forexample, banks, governments, retail stores, international organizationswith small in-country offices, and so on.

b) Wide Area Network Topology

Wide area network (WAN) topologies are network configurationsthat are designed to carry data over a great distance. Unlike LANs, whichare designed to deliver data between many systems, WAN topologies areusually point to point. Point to pointmeans that the technology wasdeveloped to support only two nodes sending and receiving data. Ifmultiple nodes need access to the WAN, a LAN will be placed behind it toaccommodate this functionality.

c) Private Circuit Topology

Leased lines are dedicated analog or digital circuits that are paid foron a flat-rate basis. This means that whether you use the circuit or not, youare paying a fixed monthly fee. Leased lines are point-to-pointconnectionsthey are used to connect one geographical location toanother. The maximum throughput on a leased line is 56Kbps.

VPN

a) Hub-and-spoke Topology

The most commonly encountered topology is a hub-and-spoketopology, where a number of remote offices (spokes) are connected to acentral site (hub). The remote offices usually can exchange data (there areno explicit security restrictions on inter-office traffic), but the amount of

data exchanged between them is negligible. The hub-and-spoke topologyis used typically in organizations with strict hierarchical structures, forexample, banks, governments, retail stores, international organizationswith small in-country offices, and so on.

b) Partial- or Full-mesh Topology

Not all customers can implement their networks with the hub-and-spoke topology discussed in the previous section for a variety ofreasons, for example: The organization might be less hierarchical in structure, requiring

data exchange between various points in the organization. The applications used in the organization need peer-to-peer

communication (for example, messaging or collaboration systems).


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For some multinational corporations, the cost of hub-and-spoketopology might be excessive due to the high cost of internationallinks.

In these cases, the overlay VPN model best suited to theorganization's needs would be a partial-mesh model, where the sites in the

VPN are connected by VCs dictated by traffic requirements (whicheventually are dictated by business needs). If not all sites have directconnectivity to all other sites the topology is called partial mesh; if everysite has a direct connection to every other site, the topology is called a fullmesh.

c) Hybrid Topology

Large VPN networks built with an overlay VPN model tend tocombine hub-and-spoke topology with the partial-mesh topology. Forexample, a large multinational organization might have access networks ineach country implemented with a hub-and-spoke topology, whereas the

international core network would be implemented with a partial-meshtopology.

d) Simple Extranet Topology

The Intranet topologies discussed so far are concerned mostly withthe physical and logical topology of the VPN network, as dictated by theVC technology by which the overlay VPN model is implemented. In theextranet topologies, we focus more on the security requirements of theVPN network, which then can be implemented with a number of differenttopologies, either with the overlay or peer-to-peer VPN model.

e) VPDN TopologyThe Virtual Private Dial-up Network (VPDN) service usually is

implemented by tunneling PPP frames exchanged between the dial-upuser and his home gateway in IP packets exchanged between the networkaccess servers.

f) Managed Network VPN Topology

The last VPN topology discussed in this chapter is the topologyused by service providers to manage the customer-premises routers in amanaged network service. In a typical setup, the service providerprovisions a number of routers at customer sites, connecting them through

VCs implemented with Frame Relay or ATM and builds a separate hub-and-spoke topology connecting every customer router with the NetworkManagement Center (NMC).


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C. Network Architecture

Leased Line

VPN


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D. Network Algorithm

Leased Line

These are the major tasks when configuring the router: Configuring Global Parameters

Configuring Security Configuring the Fast Ethernet Interface Configuring the Serial Interface Configuring Dynamic Routing Parameters Configuring Command-Line Access to the Router

Configuring Global Parameters

Follow these steps to configure the router for global parameters.

Command Task

Step 1 configure terminal Enter configuration mode.

Step 2 service timestampsdebug date time msec

Configure the router to show the dateand time of all debugs messages.

This command is optional, but it isrecommended if you use debugcommands to troubleshoot yourconfiguration.

Step 3 service timestamps log

date time msec

Configure the router to show the date

and time of all log messages.This command is optional, but it isrecommended if you use theverification steps described in thisguide. This feature is enabled for all thecommand output examples shown inthis guide.

Step 4 ip subnet-zero Configure the router to use subnet zerofor interface addresses and routingupdates.

Step 5 no ip domain-lookup Disable the IP Domain Name System(DNS)-based host name-to-addresstranslation on the router.

Step 6 ipxrouting0000.0caa.1111

Enable IPX routing, and configure therouter with an IPX address.

Configuring Security

Follow these steps to configure the router with security measures.


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Command Task

Step 1 enablepassword

Specify a password to prevent unauthorizedaccess to the router.

Step 2 hostnameRouter Configure the router with a host name, whichis used in prompts and default configurationfilenames.

For PPP authentication, the host nameentered with this command must match theusername of the central-site router.

Configuring the Fast Ethernet Interface

Follow these steps to configure the Fast Ethernet interface, which connects

your router to the local network.

Command Task

Step 1 interface fastethernet0 Enter configuration mode for theFast Ethernet interface.

Step 2 ip address10.1.1.1 255.0.0.0 Configure this interface with anIP address and a subnet mask.This interface must have an IPaddress assigned in order for the

serial interface to be configuredfor IP unnumbered routing.

Step 3 ipxnetwork100encapsulationsap

Enable IPX routing on thisinterface, assign the IPX networknumber, and configure theinterface for IPX SAPencapsulation.

Step 4 ipxnetwork100encapsulation

novell-ether secondary

Configure a secondary IPXnetwork that uses the default

NetWare encapsulation.

Step 5 no shutdown Enable the interface and theconfiguration changes you havejust made on the interface.

Step 6 exit Exit configuration mode for thisinterface.

Configuring the Serial Interface

Follow these steps to configure the serial interface, which connects yourrouter to the central-site router.


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Command Task

Step 1 interface serial0 Enter configuration mode for the serialinterface.

Step 2 descriptionleased line toheadquarters

Add a description of this interface tohelp you remember what is attached toit.

Step 3 ip unnumbered FastEth0 Enable IP routing on this interfacewithout assigning an IP address.

Step 4 ipx networkAAAA Enable IPX routing on this interface, andassign an IPX network number.

Step 5 encapsulation PPP Configure this interface for PPP

encapsulation.

Step 6 no shutdown Enable this interface and theconfiguration changes you have justmade on the interface.

Step 7 exit Exit configuration mode for thisinterface.

Configuring Dynamic Routing Parameters

Follow these steps to configure some dynamic routing parameters.Command Task

Step 1 router rip Enable RIP routing on the router, and enterrouter configuration mode.

Step 2 version 2 Specify the router to use RIP version 2.

Step 3 network10.0.0.0 Enable Enhanced Interior Gateway RoutingProtocol (EIGRP) for this network.

Step 4 no auto-summary

Disable automatic summarization of subnetroutes into network-level routes.

Step 5 ip classless Configure the router to forward packetsaddressed to a subnet of a network with nonetwork default route.

Step 6 exit Exit router configuration mode.

Configuring Command-Line Access to the Router

Follow these steps to configure parameters that control access to the router.


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Command Task

Step 1 line console0 Specify the console terminal line, and enterline configuration mode.

Step 2 exec-timeout5 Set the interval that the EXEC commandinterpreter waits until user input is detected.

Step 3 line vty0 4 Specify a virtual terminal for remoteconsole access.

Step 4 password Specify a password on the line.

Step 5 login Enable password checking at terminalsession login.

Step 6 end Exit configuration mode.

VPN

Configuring VPN in Windows XP Professional

For configuring the VPN connection, you need to have a static IP address of

the remote computer of your company and the host name. You can configure the

VPN connection in Windows XP Professional by the following method.

1. Click Start > Control Panel > Click Network and Internet connection > ClickNetwork Connections.

2. Here you need to create new connection and click next

3. Here click Connect to network at my work place click next.

4. Click Virtual Private Network and click next.

5. Here type the meaningful name for your company or any other network connection

and click next.

6. Here click Do not dial the initial connection and click next.

7. Here type the hostname and the IP address of the computer to which you want to

connect.

8. Press next and then press finish.

Installing VPN in Windows 2000 Professional


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Make sure that you are connected to the internet and you are also connected to the

LAN.

1. Start > Administrative Tools > Routing and Remote Access

2. Click the server name in the tree and on the action menu click Configure and

Enable Routing and Remote Access and click next.

3. Click Virtual Private Network (VPN Server) in the common configurations and click

next.

4. In the remote client protocols, make sure that the TCP/IP is included in the list.

Click yes to all available protocols and click next.

5. Select the Internet connection that will connect to the internet in the internet

connection box and click next.

6. In the IP address management box select automatically to assign the IP addressesthrough the DHCP server.

7. In the Managing Multiple Remote Access Server select this option No, I dont

want to setup this server to use Radius Server Now. Click Next > Click Finish.

8. Now right click on the Ports node and click properties now click WAN mini port

(PPTP) and then click configure.

9. Type the maximum number of the allowed simultaneous PPTP VPN connections

to this server.

Configuring VPN Server in Windows 2000

You can configure the VPN server further by the following methods.

1. Start > Admin Tools > Routing and Remote Access.

2. Right click the server name and then properties.

3. Select Enable this computer as a router on the general tab.

4. Here you have the choice to select Local Area Routing or LAN or Demand Dial

Routing click ok and close all the dialog boxes.

Configuring VPN Connection in the Client Computer


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1. Start > Settings > Network and dialup connection

2. Make new connection

3. Click next and then click connect to a private network through Internet

a. Click Automatically Dial this initial connection and select your dial up internetconnection from the list.

b. If you use cable modem then select Do not dial this initial connection.

4. Click next

5. Here type the host name and the IP address of the remote computer to which you

want to connect.

6. Type the descriptive name of the connection and click next.


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V. Technical Content

A. Hardware Requirements

Leased Line

The customer has to provide V.32 bits modem on both sides. He has to alsoarrange a router which will integrate the LAN with Internet. However UNIXmachines can also be specially configured to act as IP routers.

VPN

Applies To: Windows Server 2003, Windows Server 2003 R2, WindowsServer 2003 with SP1, Windows Server 2003 with SP2

Use the following guidelines when determining network hardwarerequirements for your VPN design:

For interfaces on the public network, use network adapters capable ofIPSec hardware offload.

Assuming that you have a 10/100 Ethernet infrastructure, set alldevices to 100 Mbps Full Duplex.

Connect interfaces on the private network directly to a high-capacityswitch that also connects the data servers and routers that remote

access clients will access frequently.

CPU Requirements

Use the following guidelines when determining CPU requirements for yourVPN design:

Processing inbound and outbound packets requires CPU cycles. Byincreasing the available processing power, you can increasethroughput.

Doubling the speed of a single processor is more effective thandoubling the number of processors.

In the case of multiprocessor platforms, binding one CPU to eachnetwork adapter can increase the efficiency of interrupt handling,freeing cycles and shrinking the performance gap between the use of alarge number of less powerful CPUs and a few faster, more expensiveCPUs.

RAM Requirements

Use the following guidelines when determining the RAM needed for VPN

servers:


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Each active connection consumes a small block of non page ablememory (approximately 40 KB). If you do not need to handle more than1,000 concurrent calls from remote access users, 512 MB of RAM isadequate.

If you require the capacity to handle more than 1,000 concurrent calls,for every 1,000 concurrent calls provide an extra 128 MB of RAM overrecommended RAM capacity for the server, plus a base of 128 MBmore for remote access and related services.


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B. Software Requirements

Leased Line

The software requirement for this type of environment depends onwhat type of application the user is looking for.

VPN

System requirements

OS/400 Version 5 Release 2 (5722-SS1) or later

Digital Certificate Manager (5722-SS1 Option 34)

iSeries Access for Windows (5722-XE1)

iSeries Navigator

Network component of iSeries Navigator

Set the retain server security data (QRETSVRSEC *SEC) system value to 1

TCP/IP must be configured, including IP interfaces, routes, local host name,

and local domain name

Client requirements

A workstation with a Windows 32-bit operating system properly connected to

your system, and configured for TCP/IP

A 233 Mhz processing unit

32 MB RAM for Windows 95 clients

64 MB RAM for Windows NT 4.0 and Windows 2000 clients

iSeries Access for Windows and iSeries Navigator installed on the client PC

Software that supports the IP Security (IPSec) protocol

Software that supports L2TP, if remote users will use L2TP to establish a

connection with your system


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C. Application Area

Leased Line

a. Site to site data connectivity

Terminating a leased line with two routers can extend networkcapabilities across sites. Leased lines were first used in the 1970s byenterprise with proprietary protocols such as IBM System NetworkArchitecture and Digital Equipment DECnet, and with TCP/IP in Universityand Research networks before the Internet became widely available. Notethat other Layer 3 protocols were used such as Novell IPX on enterprisenetworks until TCP/IP became ubiquitous in the 2000s. Today, point topoint data circuits are typically provisioned as either TDM, Ethernet, orLayer 3 MPLS.

b. Site to site PBX connectivity

Terminating a leased line with two PBX allowed customers to by-pass PSTN for inter-site telephony. This allowed the customers to managetheir own dial (and to use short extensions for internal telephone number)as well as to make significant savings if enough voice traffic was carriedacross the line (especially when the savings on the telephone billexceeded the fixed cost of the leased line).

c. Site to network connectivity

As demand grew on data network telcos started to build more

advanced network using packet switching on top of their infrastructure.Thus number of telecommunication companies added ATM, Frame-relayor ISDN offerings to their services portfolio. Leased lines were used toconnect the customer site to the telco network access point.

d. International Private Lease Circuit

An International Private Leased Circuit (IPLC) functions as a point-to-point private line. IPLCs are usually Time-division multiplexing (TDM)circuits that utilize the same circuit amongst many customers. The natureof TDM requires the use of a CSU/DSU and a router. Usually the routerwill include the CSU/DSU.

Then came the Internet (in the mid-1990s) and since the mostcommon application for leased line is to connect a customer toits ISP Point of presence. With the changes that Internet brought in thenetworking world other technologies were developed to proposealternative to Frame-relay or ATM networks such as VPN's (hardware andsoftware) and MPLS networks (that are in effect an upgrade to TCP/IP ofexisting ATM/Frame-relay infrastructures).
http://en.wikipedia.org/wiki/System_Network_Architecturehttp://en.wikipedia.org/wiki/System_Network_Architecturehttp://en.wikipedia.org/wiki/DECnethttp://en.wikipedia.org/wiki/TCP/IPhttp://en.wikipedia.org/wiki/Network_Layerhttp://en.wikipedia.org/wiki/Time-Division_Multiplexinghttp://en.wikipedia.org/wiki/Telephone_companyhttp://en.wikipedia.org/wiki/Packet_switchinghttp://en.wikipedia.org/wiki/Time-division_multiplexinghttp://en.wikipedia.org/wiki/CSU/DSUhttp://en.wikipedia.org/wiki/ISPhttp://en.wikipedia.org/wiki/Point_of_presencehttp://en.wikipedia.org/wiki/VPNhttp://en.wikipedia.org/wiki/VPNhttp://en.wikipedia.org/wiki/Point_of_presencehttp://en.wikipedia.org/wiki/ISPhttp://en.wikipedia.org/wiki/CSU/DSUhttp://en.wikipedia.org/wiki/Time-division_multiplexinghttp://en.wikipedia.org/wiki/Packet_switchinghttp://en.wikipedia.org/wiki/Telephone_companyhttp://en.wikipedia.org/wiki/Time-Division_Multiplexinghttp://en.wikipedia.org/wiki/Network_Layerhttp://en.wikipedia.org/wiki/TCP/IPhttp://en.wikipedia.org/wiki/DECnethttp://en.wikipedia.org/wiki/System_Network_Architecturehttp://en.wikipedia.org/wiki/System_Network_Architecture


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VPN

a. System updates

Update packages to perform security updates or installapplications from software repositories on the internet.

b. Browse the web

Use a web browser to view web pages.

c. Using E-mail

There are three ways to access your e-mail, web mail from aweb browser, accessing the exchange server from an e-mail clientand using the POP/IMAP/SMTP servers from an e-mail client.

d. Using instant messaging

There are many different instant messaging networks each

using their own network protocols that do not talk with each other.

You need to select a client that works with your chosen network or

a client that works on many different networks.

e. Access remote shells

A remote shell is command line access to a remote machine.There are many different ways to get a remote shell but only SecureShell (SSH) and the less secure telnet are available.

f. Streaming video


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D. Security

Leased Line

A leased line is also referred to as a dedicated line, because it isdedicated to the two locations it is connecting. Data and information

are transmitted without the use of the Internet. This makes theconnection secure, and files sent over the connection are safe fromhackers.

VPN

Secure VPNs use cryptographic tunneling protocols toprovide confidentiality by blocking intercepts and packet sniffing, allowingsender authentication to block identity spoofing, and

provide message integrity by preventing message alteration.Secure VPN protocols include the following:

IPsec (Internet Protocol Security) was developed by the InternetEngineering Task Force (IETF), and was initially developed for IPv6, whichrequires it. This standards-based security protocol is also widely usedwith IPv4. Layer 2 Tunneling Protocol frequently runs over IPsec. Itsdesign meets the most security goals: authentication, integrity, andconfidentiality. IPsec functions by summarizing an IP packet in conjunctionwith a surrounding packet, and encrypting the outcome.

Transport Layer Security (SSL/TLS) can tunnel an entire network'straffic, as it does in the OpenVPN project, or secure an individualconnection. A number of vendors provide remote access VPN capabilitiesthrough SSL. An SSL VPN can connect from locations where IPsec runsinto trouble with Network Address Translation and firewall rules.

Datagram Transport Layer Security (DTLS) is used in Cisco's next-generation VPN product, Cisco AnyConnect VPN, to solve theissues SSL/TLS has with tunneling over UDP.

Microsoft Point-to-Point Encryption (MPPE) works with their Point-to-Point Tunneling Protocol and in several compatible implementations on

other platforms. Microsoft introducedSecure Socket Tunneling Protocol (SSTP) inWindows Server 2008 and Windows Vista Service Pack 1. SSTPtunnels Point-to-Point Protocol (PPP) or Layer 2 Tunneling Protocol trafficthrough an SSL 3.0 channel.

MPVPN (Multi Path Virtual Private Network). Ragula SystemsDevelopment Company owns the registered trademark "MPVPN".

Secure Shell (SSH) VPN -- OpenSSH offers VPN tunneling to secureremote connections to a network or inter-network links. This should not beconfused with port forwarding. OpenSSH server provides a limited numberof concurrent tunnels and the VPN feature itself does not support personalauthentication
http://en.wikipedia.org/wiki/Cryptographichttp://en.wikipedia.org/wiki/Tunneling_protocolhttp://en.wikipedia.org/wiki/Confidentialityhttp://en.wikipedia.org/wiki/Intercepthttp://en.wikipedia.org/wiki/Packet_sniffinghttp://en.wikipedia.org/wiki/Authenticationhttp://en.wikipedia.org/wiki/Digital_identityhttp://en.wikipedia.org/wiki/Spoofing_attackhttp://en.wikipedia.org/wiki/Messagehttp://en.wikipedia.org/wiki/Integrity#Cryptographyhttp://en.wikipedia.org/wiki/IPsechttp://en.wikipedia.org/wiki/IPv6http://en.wikipedia.org/wiki/IPv4http://en.wikipedia.org/wiki/Layer_2_Tunneling_Protocolhttp://en.wikipedia.org/wiki/Tunneling_protocolhttp://en.wikipedia.org/wiki/OpenVPNhttp://en.wikipedia.org/wiki/Network_Address_Translationhttp://en.wikipedia.org/wiki/Datagram_Transport_Layer_Securityhttp://en.wikipedia.org/wiki/Cisco_Systems#Cisco_AnyConnect_VPN_Clienthttp://en.wikipedia.org/wiki/Transport_Layer_Securityhttp://en.wikipedia.org/wiki/Microsoft_Point-to-Point_Encryptionhttp://en.wikipedia.org/wiki/Point-to-Point_Tunneling_Protocolhttp://en.wikipedia.org/wiki/Point-to-Point_Tunneling_Protocolhttp://en.wikipedia.org/wiki/Secure_Socket_Tunneling_Protocolhttp://en.wikipedia.org/wiki/Secure_Socket_Tunneling_Protocolhttp://en.wikipedia.org/wiki/Windows_Vistahttp://en.wikipedia.org/wiki/Point-to-Point_Protocolhttp://en.wikipedia.org/wiki/Layer_2_Tunneling_Protocolhttp://en.wikipedia.org/wiki/Transport_Layer_Securityhttp://en.wikipedia.org/wiki/Trademarkhttp://en.wikipedia.org/wiki/Secure_Shellhttp://en.wikipedia.org/wiki/OpenSSHhttp://en.wikipedia.org/wiki/OpenSSHhttp://en.wikipedia.org/wiki/Secure_Shellhttp://en.wikipedia.org/wiki/Trademarkhttp://en.wikipedia.org/wiki/Transport_Layer_Securityhttp://en.wikipedia.org/wiki/Layer_2_Tunneling_Protocolhttp://en.wikipedia.org/wiki/Point-to-Point_Protocolhttp://en.wikipedia.org/wiki/Windows_Vistahttp://en.wikipedia.org/wiki/Secure_Socket_Tunneling_Protocolhttp://en.wikipedia.org/wiki/Point-to-Point_Tunneling_Protocolhttp://en.wikipedia.org/wiki/Point-to-Point_Tunneling_Protocolhttp://en.wikipedia.org/wiki/Microsoft_Point-to-Point_Encryptionhttp://en.wikipedia.org/wiki/Transport_Layer_Securityhttp://en.wikipedia.org/wiki/Cisco_Systems#Cisco_AnyConnect_VPN_Clienthttp://en.wikipedia.org/wiki/Datagram_Transport_Layer_Securityhttp://en.wikipedia.org/wiki/Network_Address_Translationhttp://en.wikipedia.org/wiki/OpenVPNhttp://en.wikipedia.org/wiki/Tunneling_protocolhttp://en.wikipedia.org/wiki/Layer_2_Tunneling_Protocolhttp://en.wikipedia.org/wiki/IPv4http://en.wikipedia.org/wiki/IPv6http://en.wikipedia.org/wiki/IPsechttp://en.wikipedia.org/wiki/Integrity#Cryptographyhttp://en.wikipedia.org/wiki/Messagehttp://en.wikipedia.org/wiki/Spoofing_attackhttp://en.wikipedia.org/wiki/Digital_identityhttp://en.wikipedia.org/wiki/Authenticationhttp://en.wikipedia.org/wiki/Packet_sniffinghttp://en.wikipedia.org/wiki/Intercepthttp://en.wikipedia.org/wiki/Confidentialityhttp://en.wikipedia.org/wiki/Tunneling_protocolhttp://en.wikipedia.org/wiki/Cryptographic


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VI. Implementation

A. Cost and Benefit Analysis

Leased Line

Item Description Price

Leased linemodem (TD-36485)

The TD-36 485 is designed to function reliablywithin industrial environments and in areas ofhigh level interference. The modem has an RS-232 and RS-422/485 interface supportingterminal data rates up to 115 Kbit/s. The TD-36485 is a V.34 modem meaning that it cansupport bidirectional data rates of up to 33.6Kbit/s on the PSTN or leased line side. Fastconnect ensures that leased lines can re-establish connections in the range of 5seconds.

27 914Php

Cisco Cable

V.35

V.35 circuits interface with everything from

RS232 to T1, so we also provide any cables

needed to make the transition. And since we

make them to any length, the end user never

has a mess of surplus cable to choke his

raceways, cable trays or under floor space.

1,500Php

VPN

Item Description Price

DFL-210NetworkSecurity Firewall

The NetDefend family of Firewall/VPN SecurityAppliances is D-Links answer for hardware-based network security. The new D-LinkNetwork Security Firewall (DFL-210) is aneasy-to-deploy VPN and firewall solutiondesigned specifically for the Small Office /Home Office (SOHO) market that demandssuperior performance and security.

$439.99 /19,408Php

D-Link's VPN

Client Software

Allows users to communicate with company

headquarters quickly and securely.

$49.99 /2,166Php


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B. Strengths and Weaknesses

Leased Line

Strengths

It provides permanent, reliable, high-speed connectivity as compared to thetemporary connectivity of dial up access. The quality of the connection is farsuperior to what is normally available through dialup, because of the digitalsignaling, less noise, fewer exchanges etc.

Weakness

Leased bandwidth prices are quite high, compared to dialup bandwidth ofcomparable size. Entry level annual port prices are also high at present, sothat this access method is only feasible beyond a fairly high threshold level.

Permanent connectivity to the Net exposes the organization to a variety ofthreats including hacking, malicious code including active vandals, viruses,Trojan Horses, macros, denial of service attacks etc.

VPN

Strengths

a) Cost Savings - By leveraging third party networks, with VPN,organizations no longer have to use expensive leased or frame relaylines and are able to connect remote users to their corporate networksvia a local Internet service provider (ISP) instead of via expensive 800-numberor long distance calls to resource-consuming modem banks.

Eliminating the need for expensive long-distance leased lines Reducing long-distance telephone charges Offloading support costs

b) Security - VPNs provide the highest level of security using advancedencryption and authentication protocols that protect data fromunauthorized access.

c) Scalability - VPNs allow corporations to utilize remote accessinfrastructure within ISPs. Therefore, corporationsare able to add a virtually unlimited amount of capacity without addingsignificant infrastructure.

d) Compatibility with Broadband Technology - VPNs allow mobileworkers, telecommuters and day extenders to take advantage of high-speed, broadband connectivity, such as DSL and Cable, when gainingaccess to their corporate networks, providing workers significantflexibility and efficiency.

e) VPNs enable you to create secure, business-critical communicationlinks over the Internet.

f) Give telecommuters and mobile workers secure access to your LANg) Share resources with partners


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Weaknesses

a) Quality of Service. Unlike circuit-switched or leased line data services,

VPN links (or tunnels) over public routed networks do not typically offerany end-to-end throughput guarantees. In addition, packet loss isvariable and can be very high, and packets can be delivered out-of-order and fragmented

b) Security. VPN connections are made by first connecting to a POP ofthe public network, and then using that network to reach a remote peerto form a private tunnel. Once the connection has been made to thePOP, unsolicited data from other users of the public network can bereceived, and the exposure to "attacks" requires comprehensive andcomplex security measures.

c) Bandwidth reservation or Quality of Service (QoS) at the enterprise or

central site. Bandwidth reservation refers to the ability to "reserve"transmission bandwidth on a network connection for particular classesor types of traffic. It is much harder to achieve with VPNs thantraditional networks. Some reservation can be done on out-boundtraffic, but for inbound reservation to be achieved, the VPN carrierwould need to help

d) Two-way calling. Small office/home office sites that use ISDN toaccess a central site directly enjoy the capabilities of two-way calling,e.g. if the link is idle (the inactivity timer has fired and disconnected thecall) and traffic needs to flow from the central site to the remote site,the central site can initiate the call. In a VPN network, this is a

capability missing from common ISP offerings today. Call-back is arelated topic; offering to pick up the dial-in costs incurred by partnersand customers is also difficult.

e) Overhead. VPN tunnels impose overhead for dial-in users: encryptionalgorithms may impact the performance of the user's system, there willbe an increased protocol header overhead, authentication latency willincrease, PPP and IP compression will perform poorly (compared to adirect link), and modem compression won't work at all.

f) Support issues. Replacing direct-dial links with VPN tunnels mayproduce some very painful fault-finding missions. Due to the complexityof VPN carrier networks, the opportunities for "hand-washing" areenormous.

g) Reconnection time. Using tunneling may increase the reconnectiontime for dial users. With the VPN carrier L2TP model, the client has togo through two authentication phases: one on contacting the VPNcarrier POP, and another on contact with the enterprise SecurityGateway.

h) Multimedia. Applications such as video conferencing only workacceptably over low latency links that can offer the required minimumthroughput. Currently on the Internet, latency and throughput can varyalarmingly. Multi-channel data services, such as ISDN and xDSL solve

this problem in the short term, allowing the "data" channel to be used


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for VPN tunneling, and a separate "voice" channel to be used forbusiness telephone calls or video conferencing.

i) Encryption. When using encryption to protect a tunnel, datacompression is no longer achievable as encrypted data is notcompressible. This means that hardware compression over a modem

connection is not possible.j) Packet loss. A VPN tunnel can sometimes suffer high packet loss and

can reorder packets. Reordering can cause problems for some bridgedprotocols, and high packet loss may have an impact on the optimalconfiguration of higher-layer protocols.


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C. Future Development

Leased Line

LEASED-LINE REPLACEMENTBridge Wave utilizes wireless gigabit links to provide a high performance fiber

optic replacement at significant savings compared to leased lines formetropolitan area networks.

Advantages of Bridge Waves Gigabit Wireless Links:

o High Capacity full-rate, full-duplex GigE capacity

o Reliability carrier-class 99.999% availability

o Security inherent and advanced security options

o Privacy dedicated connectivity between buildings

o Scalability bandwidth on demand, easily upgradeable

o Cost eliminate recurring leased line costso Installation Easy installation within days

o Distance up to 6 miles (9 km)

VPN

Virtual private networks have grown in popularity as businesses to save

money on remote network access for employees. Many corporations have

also adopted VPNs as a security solution for privateWi-Fiwireless networks.

Expect a continued gradual expansion in use of VPN technology to continue

in the coming years.
http://compnetworking.about.com/cs/wireless80211/g/bldef_wifi.htmhttp://compnetworking.about.com/cs/wireless80211/g/bldef_wifi.htmhttp://compnetworking.about.com/cs/wireless80211/g/bldef_wifi.htmhttp://compnetworking.about.com/cs/wireless80211/g/bldef_wifi.htm


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D. Summary/Conclusion

Leased Line

A leased line is a private high-performance circuit leased by a commoncarrier between a customer and a service providers network. It is rented on

an annual basis and usually carries voice and data or both.

Leased lines are mostly used for either internet access (InternetLeased Line) or used privately between two customer sites (Point to PointLeased Line). Unlike a dial-up connection, a leased line is always active.Similarly unlike broadband, a leased line is not contended or shared anddelivers dedicated guaranteed bandwidth straight to the internet backbone.Customers pay a premium for a leased line and it is supported by acomprehensive Service-Level Agreement (SLA) with a guaranteed fix timeand a compensation clause. Otherwise referred to as a point to point, privatecircuit, private line or dedicated access.

VPN

A Virtual Private Network (VPN) is a network technology that creates a

secure network connection over a public network such as the Internet or a

private network owned by a service provider. Large corporations, educational

institutions, and government agencies use VPN technology to enable remote

users to securely connect to a private network.

A VPN can connect multiple sites over a large distance just like a WideArea Network (WAN). VPNs are often used to extend intranets worldwide to

disseminate information and news to a wide user base. Educational

institutions use VPNs to connect campuses that can be distributed across the

country or around the world.

In order to gain access to the private network, a user must beauthenticated using a unique identification and a password. An authenticationtoken is often used to gain access to a private network through a personalidentification number (PIN) that a user must enter. The PIN is a unique

authentication code that changes according to a specific frequency, usuallyevery 30 seconds or so.

Mobile users today often access their company networks through avirtual private network. When a mobile user connects to a main office using astandard Internet connection, a virtual private network(VPN) provides themobile user with a secure connection to the company network server, as if theuser has a private line. VPNs help ensure that data is safe from beingintercepted by unauthorized people by encrypting data as it transmits from anotebook computer, smart phone, or other mobile device.
http://connectivity.onestopclick.com/rfq/8/leased-line.htmhttp://connectivity.onestopclick.com/rfq/8/leased-line.htmhttp://connectivity.onestopclick.com/rfq/7/point-to-point.htmhttp://connectivity.onestopclick.com/rfq/7/point-to-point.htmhttp://connectivity.onestopclick.com/rfq/7/point-to-point.htmhttp://connectivity.onestopclick.com/rfq/7/point-to-point.htmhttp://connectivity.onestopclick.com/rfq/7/point-to-point.htmhttp://connectivity.onestopclick.com/rfq/7/point-to-point.htmhttp://connectivity.onestopclick.com/rfq/8/leased-line.htmhttp://connectivity.onestopclick.com/rfq/8/leased-line.htm


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VII. References/BibliographyLeased Line

http://technet.microsoft.com/en-us/library/cc700841.aspx

http://sg.pacnet.com/internet/leased-line/

http://www.bridgewave.com/solutions/leased-line-replacement.cfm

http://www.hso.co.uk/leased-lines/leased-line-networking/leased-line-networking-how-to-

use-leased-lines-to-create-a-wide-area-network/

VPN

http://cba.unomaha.edu/faculty/garfathr/web/vpn_pros_cons.html

http://whatismyipaddress.com/vpn

http://compnetworking.about.com/od/vpn/a/vpn_tutorial.htm

http://etutorials.org/Networking/MPLS+VPN+Architectures/Part+2+MPLS-

based+Virtual+Private+Networks/Chapter+7.+Virtual+Private+Network+VPN+Implem

entation+Options/Typical+VPN+Network+Topologies/

http://www.emory.edu/BUSINESS/et/P98/vpn/

http://www.ncl.ac.uk/iss/netcomms/network/services/vpn/dock.html#task2

http://www.dlink.com/products/?pid=512
http://technet.microsoft.com/en-us/library/cc700841.aspxhttp://technet.microsoft.com/en-us/library/cc700841.aspxhttp://sg.pacnet.com/internet/leased-line/http://sg.pacnet.com/internet/leased-line/http://www.bridgewave.com/solutions/leased-line-replacement.cfmhttp://www.bridgewave.com/solutions/leased-line-replacement.cfmhttp://www.hso.co.uk/leased-lines/leased-line-networking/leased-line-networking-how-to-use-leased-lines-to-create-a-wide-area-network/http://www.hso.co.uk/leased-lines/leased-line-networking/leased-line-networking-how-to-use-leased-lines-to-create-a-wide-area-network/http://www.hso.co.uk/leased-lines/leased-line-networking/leased-line-networking-how-to-use-leased-lines-to-create-a-wide-area-network/http://cba.unomaha.edu/faculty/garfathr/web/vpn_pros_cons.htmlhttp://cba.unomaha.edu/faculty/garfathr/web/vpn_pros_cons.htmlhttp://whatismyipaddress.com/vpnhttp://whatismyipaddress.com/vpnhttp://compnetworking.about.com/od/vpn/a/vpn_tutorial.htmhttp://compnetworking.about.com/od/vpn/a/vpn_tutorial.htmhttp://etutorials.org/Networking/MPLS+VPN+Architectures/Part+2+MPLS-based+Virtual+Private+Networks/Chapter+7.+Virtual+Private+Network+VPN+Implementation+Options/Typical+VPN+Network+Topologies/http://etutorials.org/Networking/MPLS+VPN+Architectures/Part+2+MPLS-based+Virtual+Private+Networks/Chapter+7.+Virtual+Private+Network+VPN+Implementation+Options/Typical+VPN+Network+Topologies/http://etutorials.org/Networking/MPLS+VPN+Architectures/Part+2+MPLS-based+Virtual+Private+Networks/Chapter+7.+Virtual+Private+Network+VPN+Implementation+Options/Typical+VPN+Network+Topologies/http://etutorials.org/Networking/MPLS+VPN+Architectures/Part+2+MPLS-based+Virtual+Private+Networks/Chapter+7.+Virtual+Private+Network+VPN+Implementation+Options/Typical+VPN+Network+Topologies/http://www.emory.edu/BUSINESS/et/P98/vpn/http://www.emory.edu/BUSINESS/et/P98/vpn/http://www.ncl.ac.uk/iss/netcomms/network/services/vpn/dock.html#task2http://www.ncl.ac.uk/iss/netcomms/network/services/vpn/dock.html#task2http://www.dlink.com/products/?pid=512http://www.dlink.com/products/?pid=512http://www.dlink.com/products/?pid=512http://www.ncl.ac.uk/iss/netcomms/network/services/vpn/dock.html#task2http://www.emory.edu/BUSINESS/et/P98/vpn/http://etutorials.org/Networking/MPLS+VPN+Architectures/Part+2+MPLS-based+Virtual+Private+Networks/Chapter+7.+Virtual+Private+Network+VPN+Implementation+Options/Typical+VPN+Network+Topologies/http://etutorials.org/Networking/MPLS+VPN+Architectures/Part+2+MPLS-based+Virtual+Private+Networks/Chapter+7.+Virtual+Private+Network+VPN+Implementation+Options/Typical+VPN+Network+Topologies/http://etutorials.org/Networking/MPLS+VPN+Architectures/Part+2+MPLS-based+Virtual+Private+Networks/Chapter+7.+Virtual+Private+Network+VPN+Implementation+Options/Typical+VPN+Network+Topologies/http://compnetworking.about.com/od/vpn/a/vpn_tutorial.htmhttp://whatismyipaddress.com/vpnhttp://cba.unomaha.edu/faculty/garfathr/web/vpn_pros_cons.htmlhttp://www.hso.co.uk/leased-lines/leased-line-networking/leased-line-networking-how-to-use-leased-lines-to-create-a-wide-area-network/http://www.hso.co.uk/leased-lines/leased-line-networking/leased-line-networking-how-to-use-leased-lines-to-create-a-wide-area-network/http://www.bridgewave.com/solutions/leased-line-replacement.cfmhttp://sg.pacnet.com/internet/leased-line/http://technet.microsoft.com/en-us/library/cc700841.aspx

Comparative Study of Virtual Private Network and Leased Line

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