Viop phone - Voice Over IP

Although we’re presenting some typical numbers here, you should run the numbers using your own particular configuration. The most beneficial comparisons of a VPN occur when compared to a dedicated, line−based network or one that makes extensive use of long distance dial−up lines. If you are already using a shared network (Frame Relay or ATM), the cost savings are not so striking. Consider that a VPN box at each location might cost $5,000 including installation; multiplied by seven sites is equal to $35,000. Now, how long will it take to save this cost if you substitute your ISP charges for each location and subtract the cost of your existing T1 or Frame Relay network? If you had six T1s at $5,000/month, you might now have seven T1 access lines from your ISP at $3,000 or $4,000/month. The $7,000/month savings will pay off the $35,000 investment in 5 months. If your Frame Relay service is costing $1,000/month per location, the break−even point doesn’t happen in any reasonable period. Using remote access server and dial−up lines is cheaper to install, costing about $6,000 to $7,000 for about 20 users to install at the central location. Now comes the big bite, which is the long distance charge from all the remote locations. This could easily grow to $5,000/month if each of the users spent two hours online. Each working day at $0.10/minute is about $8,000/month. Plug in your own assumptions as to duration and cost of telephone calls here. (Even at 1 hr/day and
$0.06/minute, that is $2,000/month for 20 users). A VPN system might cost $14,000 to install, including licenses for PC software at each location. The ISP charges that are $20/user/month, plus an ISDN line at the home shop for $100/month, means that we are saving $1,500 in monthly charges. We can pay off the system in 10 months. Again, do not assume that it will pay off in all cases. But, in all cases, it is worth the effort to perform the calculations. viop Your VPN will definitely require more network management than a dial−up system, so the cost of perhaps an additional system administrator may have to be added.

Proprietary Protocols
Most VPN products are designed strictly around IP. They will often handle other protocols, such as AppleTalk and IPX, by tunneling them inside of IP packets. This introduces both overhead and delay. If the amount of “foreign” protocol traffic is small, then this is not significant. If the bulk of your network is IPX or Apple talk, we recommend you investigate VPN vendors who will support these protocols in native mode.

VoIP VPN
The justification for doing VoIP on a VPN is primarily security, along with the reduced cost of VoIP. Depending on usage, voice generates relatively large amounts of traffic. Be sure to include this additional traffic in your sizing estimates. Our discussion of VoIP applies to whether we have a VPN or not. With a VPN, the delays due to encryption are larger, and therefore we would expect that the performance of voice over the VPN would be worse than VoIP. If we have chosen a network provider who will offer a SLA with QoS, there is a better chance for success, but the delays due to encryption and basic packet switching will still be there. With the exception of international calling, one must have a very large calling volume to make it worthwhile to put voice over the Internet and suffer the attendant quality
reduction.

Summary

VPNs can provide a cost−effective solution to have secure communications across the Internet. Performance can be improved by utilizing a national/international ISP that will offer SLAs and QoS. Choosing hardware−based over software−based VPN equipment will generally provide better performance. Choosing VPN vendors who embrace standards and support multiple standards increases your flexibility to your vendor/equipment choices. Knowing your current and anticipated traffic volumes permits you to make improved cost performance studies.

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Internet−Based VPN

the same time. The philosophical point is that a dedicated network will be overbuilt in some areas and underbuilt in others. A shared network offers the hope that we can spread the overall cost out while getting the benefits of a private network. Historically, this accounts for the popularity of shared data networks beginning with X.25, Frame Relay, ATM, and now the Internet. The Internet has become a popular, low−cost backbone infrastructure.
Because of its ubiquity, many companies now want to use a secure Virtual Private Network (VPN) over the public Internet. The challenge in designing a VPN is to exploit the technologies for both intracompany and intercompany communication while still providing security. Of course the rule of thumb we now use in an Internet Protocol (IP) network is “IP on everything.” A VPN is an extension of an organization’s private intranet across a public network (that is, the Internet), creating a secure connection essentially through a tunnel. VPNs securely convey information across the Internet connecting remote users, branch offices, and business partners into the corporate network.

VPNs are owned by the carriers, but used by corporate customers, as though the customers owned them. A VPN is a secure connection that offers the privacy and management controls of a dedicated point−to−point leased line, but actually operates over a shared routed network. In the past we saw traditional networks being built as part of a leased line, point−to−point network. This was expensive and risky. A single link error brought the network down. Later a virtual networking scenario emerged using a packet−switching technology called Frame Relay. This demanded that presubscribed links were established by being premapped in logic. VPNs are created using encryption, authentication, and tunneling, a method by which data packets in one protocol are encapsulated in another protocol. Tunneling enables traffic from multiple organizations to travel across the same network, unaware of each other, as if enclosed inside their
own private steel pipe. It is easy to jump to the conclusion that the Internet is free and, therefore, there are tremendous cost savings to be had from this free shared network. Later, we will explore some cost comparisons, but as one might guess, the relative cost benefit depends very much on each network’s geography and traffic volume.

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Using these dedicated lines between locations, organizations created a private network. The next step in the evolution of private networks was to devise a corporate−wide numbering plan and have the now intelligent PBX determine the route to the dialed destination via its peers, just like the local telephone office does. After all, other than size, there is little difference between a PBX and a telephone company central office switch!

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Prior to 1984, AT&T owned most of the network through its local Bell operating telephone companies. A layered hierarchy of office connections was designed around a five−level architecture. Each of these layers was designed around the concept of call completion. The offices were connected together with wires of various types called trunks. These trunks can be twisted pairs of wire, coaxial cables (like the CATV wire), radio (such as microwave), or fiber optics. As the convergence of voice and data networks continues, we see a revisitation to the older technologies as well as the new ones. Fiber is still the preferred medium from a carrier’s perspective. However, microwave radio is making a comeback in our telecommunications systems, linking door−to−door private−line services. Carrying voice, data, video, and high−speed Internet access is a given for a microwave system. Light−based systems, however, are limited in their use by telephone companies. It has been user demand that has brought infrared light and now Synchronous Optical Network−based (SONET) infrared systems in place. Recently, the introduction of an unguided light introduced by Lucent Technologies operates at speeds up to 2.4 Gbps to 10 Gbps. This offers the connectivity to almost anyone who can afford the system, because the right of way is no longer an issue.

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A network is a series of interconnections that form a cohesive and ubiquitous connectivity arrangement when all tied together. That sounds rather vague, so let’s look at the components of what constitutes the telecommunications network. The telecommunications network referred to here is the one that was built around voice communications but has been undergoing a metamorphosis for the past two decades. The convergence of voice and data is nothing new; we have been trying to run data over a voice network since the 1970s. However, to run data over the voice network, we had to make the data look like voice. This caused significant problems for the data because the voice network was noisy and error−prone. Reliability was a dream and integrity was unattainable, no matter what the price.
Generally speaking, a network is a series of interconnection points. The telephone companies over the years have been developing the connections throughout the world so that a level of cost−effective services can be achieved and their return on investment (ROI) can be met. As a matter of due course, whenever a customer wants a particular form of service, the traditional carriers offer two answers:

• It cannot be done technically.
• The tariff will not allow us to do that!

Regardless what the question happened to be, the telephone carriers were constantly the delay and the limiting factor in meeting the needs and demands for data and voice communications. In order to facilitate our interconnections, the telephone companies installed wires to the customer’s door. The wiring was selected as the most economical way to satisfy the need and the ROI equation. Consequently, the telephone companies installed the least expensive wiring possible.

Because they were primarily satisfying the demand for voice communications, they installed a thin wire (26−gauge) to most customers whose locations were within a mile or two from the central office. At the demarcation point, they installed the least expensive termination device (RJ−11), satisfying the standard two−wire unshielded twisted pair communications infrastructure. The position of the demarcation point depended on the legal issues involved. In the early days of the telephone network, the telephone companies owned everything, so they ran the wires to an interface point and then connected their telephone equipment to the wires at the customer’s end. The point here is that the telephone sets were essentially commodity−priced items requiring little special effect or treatment. When the data communications industry began during the late 1950s, the telephone companies began to charge an inordinate amount of money to accommodate this different service. Functionally, they were in the voice business and not the data business. As a matter of fact, to this day, most telephone companies do not know how to spell the word data! They profess that they understand this technology, but when faced with tough decisions or generic questions, few of their people can even talk about the services. How sad, they will be left behind if they do not change quickly. New regulations in the United States, in effect since the divestiture agreement, changed this demarcation point to the entrance of the customer’s building. From there, the customer hooked up whatever equipment was desired. Few people remember that in early 1980, a 2400 bps modem cost $10,000. The items that customers purchase from myriad other sources include all the pieces
we see during the convergence process. In the rest of the world today, where full divestiture or privatization has not yet taken place, the
telephone companies (or Post, Telephone, and Telegraph [PTTs]) still own the equipment. Other areas of the world have a hybrid system under which customers might or might not own their equipment. The combinations of this arrangement are almost limitless, depending on the degree of privatization and deregulation. However, the one characteristic that is common in most of the world to date is that the local provider owns the wires from the outside world to the entrance of the customer’s building. This local loop is now under constant attack from the wireless providers offering satellite service, local multipoint distribution services (LMDS), and multichannel multipoint distribution services (MMDS). Moreover, the CATV companies have installed coaxial cable or fiber, if new wiring has been installed, and they offer the interconnection to business and residential consumers alike. The Competitive Local Exchange Carriers (CLECs) who survived the bloodbath and fallout of 2000 and 2001 still remain as formidable foes to the local providers. They are installing fiber to many corporate clients (or buildings) with less expense and long−term write−off issues. The CLECs are literally walking away from the telephone companies’ local loop and using their own infrastructure. Add the x−Type Digital Subscriber Line (xDSL) family of products to this equation and the telephone companies are running out of options. The Community Antenna Television (CATV) companies are still outpacing the installation of Internet cable modems compared to the use of DSL services by the Regional Bell Operating Company (RBOC) and the CLECs. The numbers will probably change over time, but the current rate of installation is in the favor of the cable companies. This is where the CATV companies see the convergence occurring.

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