Getting Started: Selecting Dialup ConnectionsFrom Connecting to the Internet , [1] (Susan Estrada 1994)
Dialup connections are appropriate for individuals and small businesses with low- to moderate-impact applications and budgets. Dialup connections vary widely in performance and price, so it's important to know what your needs are before you start looking at providers. If you are going to use your connection primarily for fun, you can put up with some performance quirks and save money. If you are going to use your connection for business purposes, you need a more stable connection.
What Kind of Connections Are Available?
There are two types of dialup connections: online accounts or dialup IP links. Dialup IP links are usually described by the particular protocol they are running: either Serial Line Internet Protocol (SLIP) or the more advanced Point to Point Protocol (PPP).
Both types of connections can give you a lot of things to do on the network. If you are starting your Internet adventure as an individual, an online account is easy to access and less expensive. If your usage is heavy, or if you have several people on a local area network (LAN), a SLIP or PPP connection becomes necessary.
If you have an online account, you connect from your own computer using a telephone line and a modem, just as you would connect to a bulletin board. An online account is one step removed from full Internet connectivity, though, and has some important limitations. If you have a SLIP or PPP account, you also connect through a modem over a phone line, but your computer runs TCP/IP software to talk the TCP/IP protocol. A SLIP or PPP actually puts your computer on the network, and gives you full Internet access.
Online Accounts
An online account is an account on a host computer that's connected to the Internet. To the host, your computer looks like a character-based terminal, and your communications software provides terminal emulation. (VT100 is a popular terminal type supported by most systems and most communications software.) When you dial into the host computer, you must log in and supply a password to get into your account.
Many of the public access providers run UNIX, where online accounts are referred to as shell accounts. (The shell is a program that you interact with by typing commands.) You may see a UNIX prompt or you may go into a custom menu-based interface. One way or another, you can usually send and receive electronic mail. Most online accounts let you use programs like Gopher, WAIS, WWW, TELNET, FTP, or any other program available on the host. Some don't. All of the providers listed in Appendix B offer at least outbound TELNET and FTP.
The drawback of an online account is that it takes two steps to get data onto your machine. You must download the data first to the host, and then to your own computer (see Figure 5-1). The FTP utility (File Transfer Protocol) is commonly used to retrieve data from the Internet and put it on the host. Then, to download it from the host to your machine, you can use one of the standard file transfer protocols like kermit, xmodem, ymodem, or zmodem. Another way is to use the screen capture feature (most communications software packages include this) to copy data as you view it on your own computer. FTP or other Internet-based applications do not run on your computer, as they depend upon the underlying support of the TCP/IP protocols to work. Figures PDF (36.8KB; 3pp.) Figure 5-1. Double download requires transferring file via FTP from the network and then downloading it to local machine using Xmodem or other communications.
Now, this "double download" can be a benefit in disguise. It lets you retrieve big data files (that might not even fit on your own disk) and look at them on the host. You can decide if you really want to the file on your local machine after you view it--you might copy only the piece of the file that you want. Downloading to the host can save the disk space on your own computer. (Of course, you may be paying for the amount of disk space you use on the host.)
Because you read e-mail, USENET News, etc. on the host machine, you are doing all of your data processing while you are online (connected to the host). Keep this in mind if you are paying by the minute for the time you spend online.
An online account can be useful if you travel a lot. You can log in to the host machine from different computers and different locations. Your special files, network addresses, or software will be available to you. For example, if you're traveling with a portable computer, consider a provider with an 800 number or nationwide local access numbers that you can use to dial into your online account.
Online accounts work well at any speeds up to the current modem standards. (See Chapter 2 for a listing of common modem standards.) Higher speed modems or different access options (as opposed to regular telephone lines) allow your computer screen to update more quickly and also help keep your online time to a minimum. You may pay a premium for access via a higher speed modem.
Online accounts work well for individuals or small businesses who want a simple, low cost access to the Internet.
Equipment RequiredFigures PDF (36.8KB; 3pp.) Figure 5-2 shows the equipment needed for a typical online account connection. At your site, you need a computer, a modem, communication software, and a regular phone line. (Many modems come with free software.)
Figure 5-2. A dialup connection requires a modem on your end and a phone line that connects to a modem connected to the host or to a terminal server.
On the supplier's side, you either go directly into the host computer, or you connect to a modem bank and then to a terminal server. A terminal server is a device that allows for multiple modem connections into the network. Most larger providers have a terminal server.
If you do go through a terminal server, you may need to perform a TELNET session to log in to the host. This is simple to do, especially if your communications software supports scripts. With a script, you go through the motions once, then the next time you log in the scripts remember where you went and how you got there.
If not included with your modem, communications software is available as freeware, shareware, and through commercial sources. Common packages are:
InterfaceDon't overlook what you see once you connect to the host. The user interface must be something you can use productively. Extras such as good e-mail and news interfaces and custom menu-driven systems can have significant value if they save you time and improve your productivity. Check for software that simplifies your access to the Internet. Software programs can vary from command driven e-mail readers (you type in commands rather than use menus or icons) to graphical user interfaces (GUIs) that work like the operating system of your computer. Figures PDF (36.8KB; 3pp.) Figure 5-3 shows an example of CERFnet's menu system that makes an online account easier to use.
Figure 5-3. CERFnet's Internet compass screen.
Some providers stick to a basic prompt like: nic% Some have made it easier to navigate the network by simplifying basic functions. Others have made it very easy for you by providing an extensive help system online. The basic prompt can make you feel somewhat ignorant if you have had little or no prior experience with computer systems. With a good desk reference book, like Ed Krol's The Whole Internet Users Guide and Catalog, you can get along with a prompt, although it may seem challenging at times. If you are allergic to manuals or want to do as much as possible without one, look for a provider that has a menu interface or a good help system.
Installation
Presuming you have the correct equipment, installation of an online account is simple and quick. It is usually a matter of signing an agreement and receiving a telephone number to call, a login ID and password. Some providers make it easy to sign up online, allowing immediate access to the Internet.
Additional Considerations
Network availability should be taken into account when choosing an online account. You have to be able to get access to an available modem line on the provider end, and you don't want frequent busy signals. Ask them how many modems are available. How often are they all busy? When will the provider add additional modems? Answering these questions will translate back to network availability--will you be able to log in when you want to? If you want to be sure that you always have immediate access, some providers have dedicated modem connections, which means that the modem line on their end is there for your exclusive use.
The amount of disk space allotted to each online account on the host computer varies considerably. This can present a real problem if upgrade options are not available. If disk space is limited on the host, you may not be able to transfer files or store e-mail. During the preparation of this book, I had to increase my disk space allotment to handle the volume of file transfer underway. Some providers have a shared storage area available for temporary transfers while doing double downloading. Find out how much disk space you will be allotted and what it will cost to expand it if necessary. One megabyte of space is the minimum you want. Ask if a temporary area is available for use.
The total number of simultaneous users on the host computer can also be a performance factor. If a supplier tries to support too many simultaneous users, the host computer slows down, causing delays to users doing routine tasks.
Cost
Most service providers have flat rates or hourly usage charges. There are networks who have a flat rate for a fixed amount of hours or for usage within certain hours. Evaluate your needs thoroughly then compare costs. If you'll be using your connection during evening and weekend hours, check for special rates during these hours.
Be careful when evaluating different costs. Some online accounts won't allow use of anything but e-mail and USENET News. If you want to use Gopher, TELNET, etc. you have to upgrade to a higher priced account. In order to correctly evaluate cost versus benefit, ask what applications are included. Figures PDF (36.8KB; 3pp.) Figure 5-4 helps you compare costs among providers. To make the best cost comparison, estimate the time you will spend online. Light Internet users typically are online from five to 15 hours per month. Medium Internet users are online 20 to 50 hours per month. If you are a heavy Internet user, don't worry about how much time you are online; find a connection for a fixed price.
Figure 5-4. Cost comparison-online accounts.
The comparison in Figure 5-5 assumes that a user would connect during business hours, Monday through Friday, for one hour per day. In comparing the five networks, we used the criteria listed at the end of this chapter. XYZNet, the cheapest, had busy signals over a period of time when I wanted to log in to check disk space allotments. It was disqualified due to lack of adequate dialup facilities.
Figure 5-5. Sample cost comparison-online account.
All of the listed parameters were taken into account, using "local access" telephone numbers. After factoring in the toll charge from the "local" numbers, there were surprising results. At first glance, the apparent low cost solution was ABCnet with a monthly charge of $20 for unlimited usage. Unfortunately, its "local number" toll charges added up to a whopping $11.49 per hour. Instead of being the lowest cost solution, it was the most expensive choice. 123net the winner even though billing was done on hourly usage. TollFreenet was the runner up. X.25Net had a hefty hourly charge for access to a 2400 bps modem and was thus disqualified.
SLIP and PPP CONNECTIONS
With a SLIP or PPP connection, your own computer has a full Internet connection capable of sending and receiving data from other computers on the network. You can run networking applications (such as e-mail, FPT, WAIS, and WWW) locally on your computer. Another benefit of a SLIP or PPP connection is the fact that you can open up multiple sessions, allowing simultaneous interaction with different computers on the Internet. In one window you could be running an FTP session while you are using Gopher in another. You can set up your system so that e-mail can come directly to it. The option to use your own domain name is an important consideration.
SLIP and PPP should be used with modem capable of at least 9600 bps, with 14.4 kbps preferred. A SLIP or PPP connection can have difficulties with certain types of compression. Check with your supplier for recommendations regarding specific settings for your modem.
One of the drawbacks of a SLIP or PPP connection is the initial difficulty in configuring the software. I have spoken to many frustrated users during the setup process who have been ready to give up after a week or two of problems. In the end, they usually were successful in connecting. In order to use a dialup IP connection, plan on having to learn more about TCP/IP and configuration issues. A lot can be said for good documentation and technical support, and a good friend who can walk you through the process.
Equipment RequiredFigures PDF (36.8KB; 3pp.) Figure 5-6 shows the hardware needed in a SLIP or PPP connection. TCP/IP software runs on the computers accessing the router, and the SLIP or PPP software runs on the router itself. There are many implementations of SLIP and PPP software available. Table 5-1 lists a few commercial packages. The support provided by SLIP/PPP software vendors and the improved reliability of commercial implementations are often worth the money spent ($100-$700).
Table 5-1. Commercial Slip Software.
Figures PDF (36.8KB; 3pp.) Figure 5-6. A SLIP/PPP connection allows your machine to be part of a local area network.
Another option for SLIP and PPP connections is a SLIP/PPP router. This setup works better for LANs because each computer doesn't have to have a modem. (Also, you don't have to configure your own SLIP or PPP software.) The router handles the dialup setup for you, which means that except for a dialing delay while the computer "talks" to the router, the connection appears the same as a dedicated line.
A number of hardware vendors are building routers which include modems and SLIP or PPP software. Two examples are the NetHopper from Rockwell International and the NetBlazer from Telebit. They can be easily attached to a computer for a simple Internet connection. Many of the network providers will sell or rent the routers. They will usually configure the router to work with their network, providing an easy solution for Internet connectivity. A router solution is practical for small businesses. This solution is still expensive for individuals ($1500 list) when compared to a software plus modem configuration.
Installation
As noted, the installation of SLIP and PPP can be a painful process. This can be minimized by working with a knowledgeable provider who will provide technical help and moral support during the installation. In order to set up a SLIP or PPP account, you should have the following information available:
Getting signed up for a SLIP or PPP account is simple and quick. It will usually involve some kind of agreement or contact, especially if you are using a router from the provider.
Options
Deciding between SLIP and PPP is important. Another SLIP option called CSLIP is also available. CSLIP, compressed SLIP, compresses the IP address information in data, thus making file transfers faster. If you will be doing many large file transfers, you should consider CSLIP. A provider's equipment will usually support only one option: either SLIP, CSLIP, or PPP. If you feel strongly about using one type of software, ask the provider if that option is available.
Another option to track is the availability of a static IP address. This will allow you to have your own domain name. Some providers use dynamic addressing which will keep you from using your own domain name. If you are going to dialup different SLIP servers and you have a static IP address, you will need a different IP address for each server and have to change your configuration.
Cost
Most service providers have flat rates for SLIP and PPP services. A few have hourly usage charges. The jump in cost from an online account to SLIP or PPP can be large. The flat-rate services are typically ten times the cost of online accounts. If you'll use your connection during evening and weekend hours and purchase an hourly rate service, check for specials on rates for off-hours. Figures PDF (36.8KB; 3pp.) Figure 5-7 helps you compare costs among providers for SLIP or PPP connections. Remember to estimate the time you will spend online: light (five to 15 hours per month), medium (20 to 50 hours per month), or heavy (above 50 hours per month).
Figure 5-7. SLIP/PPP cost comparison.
The comparison in Figure 5-8 assumes that a user would connect during business hours, Monday through Friday, for two hours per day. Four networks were compared using the criteria listed at the end of this chapter. As in the comparison of online accounts, the hidden extra cost of toll charges to "local" dialup numbers ended up as the overriding cost consideration. XYZNet, with a fixed monthly cost and a relatively inexpensive toll charge, was the winner. 123Net came in second, with hourly usage charges. If usage was to drop by 15 minutes per day, XYZNet and 123Net would cost the same. If usage was to increase substantially, XYZNet would be the obvious choice.
Figure 5-8. Sample SLIP/PPP cost comparison.
Access Options
In addition to regular telephone lines, there are two other popular methods for dialup access: ISDN and X.25. In both cases, network providers need to have special connections installed to support access via these methods. Another consideration for access is the availability of local or toll-free access numbers.
ISDN
One alternative access method for dialup is the Integrated Services Digital Network (ISDN). ISDN lets you use a special telephone line for data and voice simultaneously, which can be cost effective. ISDN offers higher speeds over a digital link and a better quality connection than with modems. To use an ISDN connection, you need a piece of equipment that substitutes for the modem. Some workstations have ISDN equipment built into the computer. Otherwise, the ISDN interface device has a price tag between $1000 and $1500, a major step up from inexpensive modems.
ISDN has been slowly spreading throughout the US, and not everybody can get it. If you are not near a major city or your phone company has older equipment, you may have to wait years before ISDN is available. (Your phone company should have a number to call for the ISDN "deployment schedule" for your area.)
An alternative that is currently available is called Switched 56k (SW56k). This is a switched data-only service that runs at 56 kbps ("Basic Rate Interface" ISDN lets you run up to 128 kbps of data or voice). It is very much like a phone call in that it uses a normal looking phone number and takes a little while to connect (whereas ISDN connections are very quick to set up). SW56k requires special wiring and uses different lines than voice lines (whereas ISDN uses normal voice lines). It is a metered service, meaning you pay by the minute (or second), and long distance costs more than local calls. If you are using it for an Internet connection, you should use equipment that only dials up when there is data to send. If the SW56k service is used often enough, there is a point at which it becomes more cost-effective to have a dedicated 56K connection (DDS) line. The biggest advantage of SW56k is that you can call multiple locations using phone numbers, while a dedicated service ties you to a single location. This type of service would be perfect for a print shop or service bureau where customers use SW56k (or ISDN) to submit printing jobs.
ISDN offers a data rate up to 128 kbps, adding together two 64 kbps channels (called "bearer channels" in ISDN-speak). Each channel can carry voice or data, so you could have a voice call on one channel and a 64 kbps data connection on the other. Sites with ISDN can usually call sites that use SW56k, but their data rate would get chopped from 128 kbps to 56 kbps. Some phone companies are offering "single line" ISDN (possibly called "IS") which is a single 56 kbps connection. You might encounter another situation where each ISDN channel is only 56 kbps, yielding a combined data rate of 112 kbps. Check with your local phone company for their ISDN offering.
X.25
The other dialup option is an X.25 network. With an X.25 connection, you need the same equipment as you would with a normal dialup connection. While you may think of an X.25 connection as a regular telephone line, you may notice slower performance, such as a delay in seeing what you have typed. Popular X.25 networks are TYMNET and SPRINTNet. X.25 is not recommended for a SLIP or PPP connection. The additional routing information added to normal TCP/IP means X.25 links have dismal performance. However, modem connections using X.25 are quite affordable at this time.
When is long distance cheaper than a local call?
If you look at the dollars per byte transferred, X.25 networks tend to be more expensive than direct dial long distance or 800 number services. The reason for this is twofold. First, X.25 is usually only 2400 bps so it will take longer to transfer data. Second, you are paying for two connections, once to the X.25 provider and once to the Internet provider. It is easy to pay $10 per hour for 2400 bps service, a high price for a slow connection.
Toll-free versus Local Access Numbers
Finding a local phone number at the speed you want may save you large amounts of money. Some Internet providers also offer toll-free 800 numbers and bundle the cost of your call in their total charges to you for the Internet connection. While the provider's charges for such toll-free numbers may look expensive at first glance, they may save you money if you don't have a local phone number to call. Toll-free numbers are especially useful if you travel a great deal and don't want to remember (or look up) the local telephone numbers. When you are comparing the cost of 800 number service with local service, check for any toll charges you may incur from dialing the provider's closest local telephone line. You can get rates from the front of your phone book or by calling your telephone company. I was very surprised when I learned that a call from my home to my local node, a distance of 15 miles, cost $2.50 per hour. Of course, if you are not charged by message units for a local call, and your connection is local, then you can stay logged in all the time for a fixed monthly cost.
Comparing Dialup Options
You should consider whether you can upgrade from an online account to a SLIP or PPP connection. This is important if you anticipate expanding your organization. Some providers have interchangeable accounts, where you can have either type of connection. Some require different methods of access between the two. Check to see if there will be additional fees if you upgrade from an online account to a SLIP or PPP connection. Find out when the provider does scheduled maintenance of the terminal server or host computer. Make sure that it is not down during a time when you need Internet access.
Dialup Account Checklist of Questions
Online AccountsDo I have the required equipment configuration? Do I need or want the added benefit of a menu-driven system to simplify online access? How often does the provider experience busy signals? What is their procedure for adding additional modems? How much disk space do I get? How does this compare with other providers? Is the host computer congested (slow)? Is there a local number to dial? Is a toll-free number an option? Is there ISDN access? Is there X.25 access? Can I upgrade to SLIP/PPP for no additional charge? When is maintenance scheduled on the terminal server and modems? Host computer? What is the real cost of the connection? (See Figure 5-4). SLIP or PPP AccountsDo I want to connect one computer or a LAN? Do I have the required equipment configuration including software? Do I want to learn more about TCP/IP? Do I have the time to set up a SLIP or PPP connection? If not, can I get help from the provider? Do I have a domain name? Does the provider do static or dynamic addressing? How often does the provider experience busy signals? What is their procedure for adding additional modems? How much disk space do I get? How does this compare with other providers? Is the host computer congested? Is there a local number to dial? Is a toll-free number an option? Is there ISDN access? Is there X.25 access? When is maintenance scheduled on the terminal server and modems? What is the real cost of the connection? (See Figure 5-7). |
[1] Our thanks to Susan Estrada and O'Reilly and Associates for permission to reprint this chapter from Connecting to the Internet.
