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Multi-Tech Systems Voice Over IP A Primer For Resellers Instructions Manual
Multi-Tech Systems Voice Over IP A Primer For Resellers Instructions Manual
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Content Introduction............................................................................................................................. 1 Voice over IP for Multi-Location Businesses................................................................................ 1 Understanding Voice Networks............................................................................................. 2 Public Switched Telephone Network............................................................................................ 2 Private Branch Exchanges............................................................................................................. 2 The Challenge - Limited Networking Solutions........................................................................... 3 Understanding Data Networks.............................................................................................. 3 The Internet Protocol..................................................................................................................... 3 How a Typical IP Data Network Works......................................................................................... 3 Local Area versus Wide Area Networks........................................................................................ 4 Using the Internet to Extend the Network................................................................................... 5 The Opportunity - Unprecedented Connectivity Options........................................................... 5 Understanding the Converged Network............................................................................... 6 Voice over IP.................................................................................................................................... 6 Voice over IP Gateways.................................................................................................................. 6 The MultiVOIP Gateway................................................................................................................. 7 How Does it Work?......................................................................................................................... 7 Voice over IP Frequently Asked Questions........................................................................... 8 Bandwidth Requirements.............................................................................................................. 8 Voice Quality................................................................................................................................... 8 Security...........................................................................................................................................10 Standards........................................................................................................................................10 Reliability........................................................................................................................................10 Ease of Use......................................................................................................................................11 Networking Dissimilar Proprietary PBX Systems........................................................................11 Supplementary Service..................................................................................................................11 Management...................................................................................................................................11 Plugging into the Voice and Data Network..................................................................................11 Port Confi guration..........................................................................................................................12 Gatekeeper Models.........................................................................................................................12 Voice over IP Applications......................................................................................................13 Confi guring a MultiVOIP Network.........................................................................................15 Confi guring the Telephony Interface............................................................................................15 Building the VOIP Dialing Plan......................................................................................................17 Deploying the VOIP Network.........................................................................................................18 Advanced Feature Confi guration..................................................................................................18 Multi-Tech Pre-Sales and Post-Sales Support......................................................................19 VOIP Glossary of Terms...........................................................................................................21 Confi guration Guide................................................................................................................25
Copyright © 2003 Multi-Tech Systems, Inc. All rights reserved.1 Voice over IP Primer Introduction Voice over the Internet Protocol (VOIP) is one of the hottest topics for multi-location businesses of any size because of its promise to transmit voice over data networks free of charge. Instead of paying the phone company to route long distance calls between offi ces, any IP data network can route the calls over a private intranet or the public Internet and save thousands of dollars annually. The ideal customer for this technology is a business with multiple locations. We’ve found that typically 25-40% of a company’s long distance bill is spent on intra-offi ce communication. Recouping this portion of the long distance bill can add up to signifi cant savings. Many companies have invested thousands of dollars in their voice and data networks. Multi-Tech’s approach to Voice over IP is to protect that investment by tying both the voice and data network together with our MultiVOIP gateway. MultiVOIP is a point-to-point, or point-to-multipoint, IP gateway. It integrates seamlessly into the data network and operates alongside existing PBXs, or other phone equipment, to simply extend voice capabilities to remote locations. The voice traffi c essentially “rides for free” on top of the data network, using the data infrastructure and hardware already in place. With MultiVOIP, a small investment will pay for itself within the fi rst six months to one year and then start paying the company back. In our company example, which we will refer to throughout this primer, we have three locations that utilize a MultiVOIP solution: Minneapolis-corporate, Los Angeles-branch offi ce and London-branch offi ce. At headquarters, they have 60 employees and 16 phone lines. At the Los Angeles offi ce there are 12 employees and 5 phone lines. And, in London, there are 8 employees and 4 phone lines. In the following ROI analysis, you can see that even with low long distance rates, MultiVOIP will return the company’s investment within 4 months. Beyond that, the company will start to profi t from the solution. While VOIP is a compelling technology for a business to embrace, the challenge is in bringing together the two very different worlds. This primer will serve to educate you on the voice network, the data network and the new converged network utilizing our MultiVOIP gateway. In addition, it will cover many of the frequently asked questions that a data communications manager and/or telecommunications manager may have with the new technology. Finally, we will put it all together and discuss how to confi gure a MultiVOIP Voice over IP network. Return on investment within six months.Same customer making money with MultiVOIP. snoitacoLVitlu M OPIo C tsecnatsiDgnoLetuniM/tsoC/setuniMyaD/eniLPIOVitluMkcabyaP /etiSetaroproCsilopaenniM 999,1$014PVM)senil4(40.0 $ 0 9 syad931 /etiShcnarBselegnAsoL 990,1$012PVM)senil2(60.0 $ 0 6 syad351 /etiShcnarBnodnoL 990,1$012PVM)senil2(80.0 $ 0 6 syad511 Voice over IP Return on Investment
Copyright © 2003 Multi-Tech Systems, Inc. All rights reserved.2 In order to understand how voice communications would be treated in a data network, let’s fi rst take a look at the typical topologies of voice and data networks running separately. Understanding Voice Networks Public Switched Telephone Network For the past 100 years, people have relied on the Public Switched Telephone Network (PSTN), otherwise known as POTs (Plain Old Telephone Service), for voice communication. Although it is very reliable, it utilizes a very basic and ineffi cient method for making a connection called circuit-switching. To illustrate a circuit-switched connection, the following is the process that takes place when you make a phone call. First, you dial the number of the party you wish to talk to. The call is then routed through the switch at your local central offi ce (CO) to the party you are calling, opening the circuit. Depending on location, the call may be routed through multiple CO connections opening a circuit through each one. During the call, the routed line is dedicated to the two parties. This means no other information can travel over the line, even though there is plenty of bandwidth available. Private Branch Exchanges In a corporation, voice communication has traditionally been handled by proprietary platforms called private branch exchanges (PBXs). A PBX is essentially a switch used to connect a number of phones (extensions) to each other and to one or more outside phone lines. To illustrate how the PBX works, when a user picks up a phone (extension) a PBX dial tone will be heard. At this point, the user can dial any other extension on the PBX. To reach an outside line, the user typically dials a “9” (or presses a pre- programmed button) to access the PSTN network. A PBX was originally designed to save the cost of requiring a line for each user to the telephone company’s central offi ce (CO). In effect, the PBX acts like a mini-CO, owned and operated by the corporation. A limitation to the traditional PBX is that it is a location-centric platform. The networking options to extend voice communications to other remote locations (e.g. branch offi ces, sister companies, satellite offi ces, telecommuters, etc.) are few and can be costly. One option, if the remote offi ce is large enough, is to add another PBX at the remote site, and set up a private network between the two with leased lines (tie lines) purchased from the phone company. To make an outgoing call to the remote offi ce, the user would dial an “8” (or press a pre-programmed button) to access the tie line and then dial the remote offi ce extension. Tie lines, however, are expensive because they add extra monthly phone charges. And, the telecommunications manager may be faced with the challenge of tying together two dissimilar proprietary PBX systems that were not designed to be networked together.
Copyright © 2003 Multi-Tech Systems, Inc. All rights reserved.3 Another option is to provide the remote offi ce with a key telephone system. A key system is a lower priced, reduced functionality version of the headquarters PBX. Because it is a scaled down system, it isn’t designed to be networked with other phone systems. Therefore, calling a remote offi ce is like calling a separate company. Using our company example, the following diagram maps out their existing voice network. The Challenge - Limited Networking Solutions With limited networking solutions, remote offi ce workers often feel handicapped by the diffi culty of communicating with the rest of the organization. And, telecommunications managers are challenged with creating more effi cient and cost-effective voice communications in an environment that wasn’t designed for networking. Understanding Data Networks The Internet Protocol The Internet Protocol (IP) was designed specifi cally for the Internet to act as the fi rst truly universal networking language. It is like a postal carrier — its job is to faithfully transport packages (or packets) from anyone to anyone over any type of physical connection. How a Typical IP Data Network Works An IP data network is a highly distributed networking environment in which clients access information stored in servers throughout the network. These servers can be anything from giant mainframes to small departmental fi le servers running on PCs. An IP data network utilizes packet-switched connections, routers and IP addresses to communicate with the different networked devices. Packet-Switched Connections IP data, whether in the form of a Web page, a downloaded fi le or an e-mail message, travels over a system known as a packet-switched network. The sending computer chops data into small packets, with an address on each one telling the network where to send them. When the receiving computer gets the packets, it reassembles them into the original data. Company Voice Network
Copyright © 2003 Multi-Tech Systems, Inc. All rights reserved. Routers and IP Addresses A router is an advanced networking component that determines the route that IP packets of data will take. It has two separate, but related, jobs: •It ensures that information doesn’t go where it’s not needed. This is crucial for keeping large volumes of data from clogging the connection. •It makes sure that information does make it to the intended destination. In performing these two jobs, a router is extremely useful in dealing with two separate computer networks. It joins the two networks, passing information from one to the other. It also protects the networks from one another, preventing the traffi c, on one, from unnecessarily spilling over to the other. Regardless of how many networks are attached, the basic operation and function of the router remains the same. Since the Internet is one huge network made up of tens of thousands of smaller networks, its use of routers is an absolute necessity. In order to route data through a network, routers need a way to locate each other. Therefore, every device on the Internet has a unique identifying number, called an IP Address. A typical IP address looks like this: 200.2.9.1. An Internet Service Provider (ISP), or network administrator, permanently or dynamically assigns an IP address to a network device. Using our company example, the following diagram maps out their existing data network. Local Area Versus Wide Area Networks We can classify IP data network technologies as belonging to one of two basic groups: Local Area Networks (LANs) or Wide Area Networks (WANs). A LAN connects many devices that are relatively close to each other, usually in the same building. A WAN connects a smaller number of devices that can be many miles apart. Different transmission facilities can be used in a WAN to support remote operations — everything from digital connections (e.g. ISDN, cable and DSL) to dedicated T1/E1 and frame relay connections. This is one of the reasons that IP data networks offer so much fl exibility and cost-effectiveness in reaching all types of remote locations and workers. See the chart below for a bandwidth comparison of various WAN connection types. 4 WAN Connection Types Company Data Network
Copyright © 2003 Multi-Tech Systems, Inc. All rights reserved.5 Using the Internet to Extend the Network Today, instead of simply dealing with local or regional concerns, many businesses now have to think about global markets and logistics. Many companies have facilities located across the country or even around the world. And, they all need a way to maintain fast, secure and reliable communications wherever their offi ces are. Before the Internet, this meant using leased lines to maintain a private Wide Area Network between the offi ces. This private WAN has obvious advantages over a public network, like the Internet, when it comes to reliability, performance and security. But maintaining a WAN, particularly when using leased lines, can become quite expensive, rising in cost as the distance between the offi ces increases. As the popularity of the Internet grew, businesses turned to it as a means of extending their own networks. First came intranets, which are password-protected sites designed for use only by company employees. Today, many companies are creating their own intranet-based VPNs (Virtual Private Networks) to accommodate the needs of remote employees and distant offi ces. A VPN is a private network that utilizes dedicated equipment and data encryption to securely connect remote sites or users together over the public Internet. Now, fast, secure, reliable, and cost-effective data communications are a reality for branch offi ces, telecommuters and road warriors. The Opportunity - Unprecedented Connectivity Options In the past, there have been many attempts to merge voice and data networks, but it wasn’t until the Internet revolution and the widespread deployment of IP data networks that the industry at large fi nally had the right transport mechanism to support voice and data. Having a universal language that virtually all worldwide networks can understand has opened up unprecedented connectivity options now available to visionary telecommunications managers.
Copyright © 2003 Multi-Tech Systems, Inc. All rights reserved.6 Understanding the Converged Network Voice over IP Voice over IP uses the data network packet-switching method to provide a more effi cient way of sending voice communication. Packet-switching optimizes the use of network resources (bandwidth) because the channel is only occupied during the time the packet is being transmitted. Many users can share the same channel because individual packets can be sent and received in any order and the network can balance the load across various pieces of equipment. This allows several telephone calls to occupy the amount of space occupied by only one in a circuit-switched network. By migrating telephone networks to packet-switching technology they immediately gain the ability to communicate more effi ciently the way computers do. In the IP world, voice is another data application running over the IP network. In a converged environment, the PBX becomes the equivalent of a super-server (like a mainframe) that sits on the network and is accessed by remote clients (e.g. handsets or even PCs, using converged applications) anywhere on the network over any type of transmission lines. Therefore, Voice over IP solves the PBX’s networking limitations by providing a cost-effective, effi cient means of communicating over the company’s existing data network, or the Internet. Voice over IP gateways, operating alongside the company’s PBX, make it possible to maintain all existing systems and simply extend voice and the PBX’s features and functionality out to remote locations and home users. It can seamlessly tie together dissimilar proprietary PBX systems and provide networking capabilities to key telephone systems that previously weren’t available. Voice over IP Gateways The device that bridges the voice network and the data network together is called a Voice over IP (VOIP) gateway. A VOIP gateway connects directly to an existing voice network and plugs into an IP data network. It uses the network’s router to access the Internet or a private intranet. A VOIP gateway is a point-to-point, or point-to-multipoint, solution (one is required for each location). It merges voice/fax from telephones onto the IP network and then utilizes another VOIP gateway, at the remote end, to separate the voice/fax from the data network and send it back to the PBX, telephone, or fax machine. Voice/Fax “Ride Free” on the Data Network
Copyright © 2003 Multi-Tech Systems, Inc. All rights reserved.7 The MultiVOIP Gateway The MultiVOIP family of Voice over IP gateways is available in analog and digital models ranging from one to 60 ports. MultiVOIP gateways connect directly to phones, fax machines, key systems, or a PBX and plug into the data network to provide real-time, toll-quality voice connections to any offi ce on your VOIP network. With MultiVOIP, your customers will avoid the hassle and expense of replacing their existing routers, WAN connections or phone systems required by other VOIP solutions. It supports industry-standard protocols to ensure optimum interoperability and voice quality. And, users are not required to master new operating procedures. In fact, once confi gured, a MultiVOIP network can be used immediately and companies can start saving money. In our company example, the following diagram maps out their converged network using MultiVOIP Voice over IP gateways. How Does it Work? Because VOIP gateways are point-to-point solutions, they fi rst need to establish the call setup. This process requires the caller to access the local MultiVOIP gateway and then dial a telephone number/extension to reach the remote MultiVOIP gateway. A call processing technique maps this dialed number into an IP address for delivery to the remote VOIP gateway. Next, in order to merge the voice call onto the IP data network, it must be encapsulated into an IP packet. To encapsulate voice, the call is broken up into frames. The size of the frame is defi ned by the voice compression used (see bandwidth requirements on pg. 8 for more details on voice compression). Then, several frames of voice data are collected. A protocol header is added to the beginning of the voice data to indicate the destination address and data type. Finally, the packet is queued for transmission. This entire process of voice packetization takes only 10 to 20 milliseconds (ms), making it undetectable to the human ear. Converged Network How a VOIP Network Works Phone Equipment: • Uses standard dialing to make a call • Routes the call to a channel on the VOIP gateway VOIP Gateway: • Establishes call setup • Packetizes voice and telephone signaling • Applies audio compression Router: • Routes packets over the Internet/ intranet to the remote offi ce VOIP gateway
Copyright © 2003 Multi-Tech Systems, Inc. All rights reserved.8 Voice over IP Frequently Asked Questions The following section covers some of the frequently asked questions a data communications manager or telecommunications manager may have as they begin to learn how a VOIP solution can solve their telephony challenges and save them money. Bandwidth Requirements “How can I be assured that my data “pipe” will not be fl ooded by voice traffi c and negatively impact the timely delivery of data services?” One common misconception about VOIP is that it is a bandwidth hog. In reality, with the use of voice compression, voice is a very effi cient type of traffi c. A vocoder (voice encoder/decoder) provides multiple voice compression standards which range from G.723 (5.3K bps/6.3K bps) to G.729 (8K bps) to G.711 (full, uncompressed 64K bps) and can be selected on a system or a per port basis. This allows the administrator to minimize network bandwidth requirements or maximize voice quality on an offi ce- by-offi ce or user-by-user basis. With MultiVOIP, the majority of applications are optimally confi gured for voice quality with minimal bandwidth requirements by simply using the factory defaults for voice compression. As a rule of thumb, 14K bps of bandwidth per call is ideal. This includes the compressed voice packet and the IP overhead. To determine total VOIP bandwidth needed per location, take the number of VOIP ports or channels being utilized and multiply by 14K (ideal bandwidth). Then double this number, to accommodate for both voice and data traffi c, to get the total bandwidth required for optimum voice quality. Company Example: Los Angeles branch offi ce is using 2-ports 2 x 14K = 28K x 2 = 56K bps minimum bandwidth Using the formula, the company needs a minimum bandwidth of 56K bps. Since their data network already has a 128K connection, bandwidth will not be an issue (see diagram on p. 4). It should also be noted that bandwidth is used only when someone is speaking. With MultiVOIP, a silence suppression/Voice Activation Detection (VAD) feature is an option that frees unused call bandwidth for data traffi c. This is signifi cant, since callers are usually silent for 60 percent of the call. Voice Quality “I’m not yet convinced that Voice over IP can deliver business quality voice.” Independent tests of VOIP systems have shown that they are perfectly capable of delivering “toll-quality” voice. Earlier implementations were criticized for excessive noise and other quality of service issues. Today, better algorithms, quicker voice compression, and the availability of high-speed communication links have all made VOIP implementations a viable technology. The actual voice quality is affected by a number of factors: WAN bandwidth (the higher the better), voice compression (as discussed previously) and network conditions including latency, jitter and packet loss.