Glossary

browser - a World Wide Web viewing program like Netscape Navigator or Mosaic.

hit - a request for a single text or graphic file from a web page. Each web page typically consists of several separate files of this type. If the same graphic item is repeated on a page, it is considered to be a single hit even though it appears multiple times. This is because the file is actually copied from the server to the browser only once, and the browser duplicates it on the screen. Although not guaranteed, if the browser's cache is large enough, the same item appearing on multiple pages will also be considered as a single hit.

ISDN - Integrated Services Digital Network - A method of transferring digital data over regular phone lines, at a speed much higher than regular modems, typically 56K, 64K, or 128K. Each ISDN line, also called a "BRI" (Basic Rate Interface), contains 2 "B" channels capable of carrying 56K or 64K of data each. An ISDN line requires the use of a device called a Terminal Adapter instead of a modem.

The total telephone company charge to have an ISDN line in a Pennsylvania residence starts at $31 per month. The total telephone company monthly charge for a business ISDN line is approximately $40.

There are no minute-by-minute usage charges from the telephone company if you have a business ISDN line, and your hardware and software are properly configured. For example, if you purchase a SunLink WebMaster ISDN account, your total monthly bill will be approximately $79 ($39 to SunLink and $40 to the telephone company). Additionally, since you purchase the ISDN line directly from the telephone company, you are free do use it for any purpose you wish, including voice calls, fax transmissions, or to make ISDN data calls to other computer systems, even long-distance calls!.

When comparing ISDN services from various providers, make sure to inquire as to how the ISDN equipment at the provider's facility is connected to the Internet. Look out for providers who use ISDN equipment attached through serial ports to PCs. This sort of connection can cause a 128K connection to act like a 64K connection, due to the lag through the serial port and the PC. Your provider's ISDN equipment should be attached directly to their internal LAN in order to achieve the greatest speed.

MPP - Multilink Point-to-Point Protocol - A method of transferring Internet data over an ISDN terminal adapter that combines multiple 56K or 64K B-channels to provide higher bandwidth. For example, most terminal adapters can combine two B-channels to provide 112K or 128K of bandwidth.

SunLink meters MPP connections based on time X number of B channels in use. For example, if your account permits 200 B-channel hours per month, then you may use a single B-channel connection for 200 hours, 2 B-channels simultanously for 100 hours, 3 B-channels simultaneously for 67 hours, or 4 B-channels simultanously for 50 hours.

PPP - Point-to-Point Protocol - A method of transferring Internet data over a modem or ISDN terminal adapter, which allows a computer to communicate directly with other computers on the Internet. This type of protocol is required to run programs such as Netscape Navigator, Mosaic, I-Phone, or CU-SeeMe from a PC or Macintosh.

shell - A shell account (or shell access) provides text-only access to a Unix "host" computer. It is similar in function to the DOS command line. It allows the use of a wide variety of programs such as archie, email, ftp, gopher, irc, telnet, and even programming tools like compilers. A shell account is indispensable when fine tuning web pages. Experienced irc and mud users prefer shell access because it permits the use of advanced functions not possible with Windows or Macintosh programs. If a computer or modem is too slow to support a PPP or SLIP connection, a shell account can often provide the only means of accessing the Internet. Navigating around the Internet with a shell account is many times faster than with PPP programs like Netscape, since only text data is sent through the modem.

SLIP - Serial Line Interface Protocol - An older protocol to allow Internet connections via a modem or other serial device. Superceded by PPP.

VJ and Stac Compression - A method of compressing Internet data to increase the speed of data transmission. VJ compression is usually a software selectable option, and is available with most PPP connections, including ISDN. Stac compression is typically used only with high-speed ISDN connections. Not all ISDN equipment will support Stac compression.

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