Connection alternatives: ISP's and On-Line Services Dedicated Link or Dial-up Account? For the most part, your assessment of Internet access requirements will drive the kind of services you secure from Internet Service Providers (ISPs). Most large organizations will probably opt for a dedicated high-speed link that provides Internet access to all nodes on their network. However, smaller organizations and branch offices not connected to a corporate wide area network may have a tougher time justifying the cost of a dedicated Internet connection. If mobile user support is also on your agenda, a dedicated connection only gets you halfway there. You'll need to build an infrastructure to support dial-in access. Dial-up Accounts An alternative that may make sense in many situations is the use of personal dial-up Internet accounts. These us ually fall into two basic categories: those available from ISPs like PSI (Reston, Va.) and those available through commercial on-line services like CompuServe (Columbus, Ohio). Note that the characteristics separating these providers are blurring as time goes on, but it is still possible to summarize the differences. Once you've determined your needs and how they match up to the alternative providers, it's a fairly straightforward exercise to determine which is more cost-effective. ISPs Most large ISPs provide both dedicated network services as well as dial-in services. A fairly common scenario would be to contract with an ISP for a dedicated high-speed Internet connection to your headquarters network while also contracting for dial-in services for mobile users and remote office workers. Thus, billing and support services can be handled by a single vendor. Alternatively, you may find that a dedicated connection really isn't needed, either because your needs are limited to basic services like e-mail or your organization is very dispersed. Most ISPs offer a similar set of network services using SLIP or PPP dial-up connections. Some, like NetCom, provide client software specially optimized for their network. Others, like PSI, work with TCP/IP application providers. It's also becoming increasingly common for these TCP/IP applications to include scripts that allow you to connect to their preferred network and create a new account "on-the-fly," though this service is probably more appropriate for personal accounts than for corporate accounts. Once you make a SLIP or PPP connection through an ISP's network, your computer becomes a full-functioning Internet node. What this means depends, to an extent, on what servers you can access. For starters, you can access home pages using a World Wide Web browser and make connections to FTP servers around the globe. However, getting e-mail services will require appropriate accounts on the ISP's server. Most ISPs use the post office protocol (POP) for e-mail services. All mail directed to your address is delivered to a mail server maintained by the ISP. When you dial in, you make a connection to the mail server and download any new mail waiting for you. One of the key benefits of POP is the fact that you can read your mail and compose new messages off-line and thereby reduce connect time. POP doesn't work quite so well if you are accessing your new mail from multiple computer systems, since all your messages, once "popped," are stored on the client machine. Online Services Not to be outdone by upstart ISPs, the major commercial online service providers have begun to expand their Internet service offerings. The range of services is rapidly evolving, but by the end of 1995, it will be possible to access all core Internet services, including e-mail, FTP, Telnet, World Wide Web and UseNet news, from all of the major vendors. In addition, the major on-line services are gradually migrating away from their proprietary dial-up networks to standards-based IP networks. It is already possible, for example, to access America Online directly via the Internet. CompuServe is also converting its network to support PPP, so your CompuServe account can also provide you with direct access to Internet resources without the need to access explicitly the CompuServe Information Service. Dedicated Links The Range of Alternatives If individual dial-up Internet accounts don't meet your needs, the obvious alternative is a more traditional LAN-oriented connection. A wide variety of alternatives exist ranging from low-cost "dial-on-demand" connections to dedicated 45-Mbps T3 connections. Choosing what's right for you requires a tough assessment of your application requirements, especially given the fact that you may want much more than you can financially justify. For all dedicated links, you'll need a router that interfaces your LAN to the Internet. In many cases, the router will be provided by the ISP as part of the installation fee. Alternatively, you may be able to use an existing router already installed on your LAN, but most network architects shy away from this practice for a couple of reasons. First, from a maintenance standpoint, you probably don't want to impact services on your LAN directly if you need to make changes or upgrades to your Internet connection. Second, and perhaps more important, you'll probably want to set up packet filters on the Internet router for security purposes, and these filters can have a detrimental impact on router performance. Since the Internet connection is likely to be a lower-speed connection than your LAN-based routers, this performance hit will probably not be dramatic, but LAN-based routers, particularly those that are used in a collapsed-backbone configuration, are sometimes CPU-bound just dealing with LAN traffic. Dial-On-Demand Links At the low end of the performance curve are dial-on-demand routers and low-speed dedicated leased lines. Dial-on-demand routers allow you to minimize your Internet connection costs by dynamically establishing connections on an as-needed basis. For example, a PC on your LAN equipped with appropriate TCP/IP software might initiate a session with a remote Web server. The dial-on-demand router would recognize that the request is for an external connection and would automatically establish a dial-up link, usually via the Internet's Point-to-Point Protocol (PPP) through a local call to an ISP. Once the PPP connection is established, your LAN has full Internet access, albeit over a rather low-speed connection. Prices for these services usually include a sign-up cost of less than $2,000, including hardware and address assignment. Recurring charges in major metropolitan areas are typically around $150 per month for a 28,800 bps connection, plus any per-min ute charges your telecommunications carrier might charge for local calls. Dial-on-demand routers are a viable technology, but there are several issues you should evaluate in considering this option. For sites that have only occasional needs for connectivity, as might be the case if you used your Internet connection only for periodic batch transfers of e-mail messages, these connections can be cost effective. On the downside, you should anticipate significant delays in connections if you are using analog modems, since the process of dialing a remote modem, handshaking and authenticating the connection can often take 15 to 30 seconds. In addition, given today's technologies, you'll be limited to raw bit rates of 28,800 bps. Use of compression technologies can help a little, but most users grow weary of this level of performance, especially if they are accessing graphically rich Web sites or processing large downloads. Dial-On-Demand ISDN The increasing popularity of ISDN provides a slight twist on the dial-on-demand router. By equipping such a device with ISDN-capabilities, you can establish digital connections at 64 Kbps or more. Not only is this significantly faster than the analog alternative in terms of raw bit rates, but the delays in establishing connections are dramatically reduced, usually down to several seconds or less. This gives users more of an impression of online connectivity than a traditional analog setup. Dial-up ISDN LAN services typically cost around $250 per month plus local telecommunications charges. Dedicated Service Options Traditional Leased Lines Most large organizations opt for the more traditional dedicated leased-line connection for Internet services. There are a range of performance and technology options available in today's marketplace, and competition has made these services quite affordable. The two most popular service alternatives continue to be dedica ted 56-Kbps and 1.5-Mbps T1 connections, though a number of users are finding fractional T1 and, to a lesser extent, 45-Mbps T3 connections to be a better match for their needs. In most cases, you can expect to pay a base monthly fee for the service plus any "local-loop" telecommunications costs. A typical 56-Kbps connection from an ISP might cost $400 per month plus local-loop charges of around $200 per month in most metropolitan areas. T1 connections typically cost $1,000 or more per month plus local loop charges of around $500 per month. In addition to these recurring charges, there is usually a set-up fee paid both to the ISP as well as the local telecommunications service provider. The former will vary depending on what equipment is needed for your connection, but will typically be $1,200 to $10,000. In most cases, you'll need a router for the LAN-to-Internet interface and a CSU/DSU for the router to leased-line interface. You may be able to reduce your monthly local-loop charges and eliminate the installation fee by negotiating with the local telecommunications provider, particularly if local competition exists in your area and you are willing to sign a contract. Finally, you'll also need to make some provisions for maintenance of the router and CSU/DSU to allow for software upgrades and timely repair of equipment. Depending on how critical your Internet service is, you may want to consider maintaining on-site spares for all components. Frame Relay Alternatives to traditional leased-line 56-Kbps and T1 connections are becoming more popular. These services are often built around frame-relay technology, a wide area network technology that allows for the creation of permanent virtual circuits (PVCs) that provide dedicated bandwidth over a vendor-provided frame relay "cloud." This technology facilitates the deployment of circuits opt imized to meet the bandwidth demands of your site. Service is usually available at speeds ranging from 128 Kbps to full T1. In addition, some ISPs allow you to set up multiple PVCs over a single Internet connection. This can be useful, for example, if you have popular publicly accessible information servers that you wish to maintain without having a detrimental impact on the overall performance of your other Internet services. Next Return to Table of Contents November 15, 1996 Print This Page E-mail this URL