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Dialup access charges for information service providers such as America Online, CompuServe, and Prodigy is dependent on modem speedhigh-speed access at 9.6, 14.4, or 28.8 Kbps is at a higher cost per minute. Additionally, the service providers have a habit of rounding up connect time to the next full minute, with a minimum in some cases. Therefore, a 45-second connection for an e-mail flash session, can be charged as though it were a three-minute connection. In any event, the Net is not free, but it is quite reasonable for most of us. Table 13.2 provides a sampling of the costs of Internet service:
America Online | CompuServe | Prodigy* | Microsoft Network** | Fictitious ISP, Inc. | |
---|---|---|---|---|---|
Access Method | Dialup | Dialup | Dialup | Dialup | Direct (SLIP or PPP) |
Basic Monthly Fee | $9.95 or $19.95 | $9.95 or $15.00 | $9.95, $14.95 or $29.95 | $4.95 or $19.95 | $19.95 |
Access Included in Basis Fee | 5 or 20 hrs | 3 or 20 hrs | 3, 5, or 30 hrs | 3 or 20 hrs | 20 hrs |
Additional Usage | $2.95/hour | $1.95/hour | $2.95/hour or $0.05/minute | $2.00/hour | $1.00/hour |
Example Content Providers | ABC, MTV, Nickelodeon, Nick at Nite, Road and Track, Womans Day, Time, The New York Times, National Geographic, American Express | Rolling Stone, Sports Illustrated, People, Forbes, Fortune, Money, Comedy Central, CNN | Homework Helper, News Week, Newsday, Los Angeles Times | Court TV, C-SPAN, Eastman Kodak, Eddie Bauer, QVC, Home Shopping Network, RockNet, Starwave-ESPNet, Sports Zone | N/A |
*Jointly owned by Sears and IBM, Prodigy was sold in May 1996 to International Wireless.
**Alas, it would seem as though Microsoft Network may not survive. Microsoft has announced a reversal in strategy, re-focusing on its core software business, rather than ISP networking.
Dedicated Access is provided by companies specializing in that line of business. Additionally, many of the Local Exchange Carriers (LECs) and Interexchange Carriers (IXCs) are offering access arrangements using T1, Frame Relay, ISDN, and SMDS services. By way of example, Pacific Bell charges $400 per month for Internet access, plus an installation fee that ranges from $1,250 to $3,500. Transport options include Frame Relay (56 Kbps) at $125 per month and installation of $2,000. T1 (1.544 Mbps) involves a monthly charge of $1,715; SMDS (16 Mbps) is $5,200 monthly with an installation of $6,500.
The Internet is divided logically into domains. Under the terms of IPv4 (Internet Protocol version 4), these are identified as a 32-bit portion of the total address. Addresses follow a standard convention, which is similar to user@organization.domain. According to Datapro, more than 70% of the registered domain names are commercial, with growth projected to 90% by 1997.
Domain types include the following:
For example, Ray@ContextCrp.com is the address for Ray (user), at The Context Corporation (organization providing the connection), a commercial enterprise.
Domains also identify the country, in the form of a two-character country code. Country codes are appended to the standard address, and are necessary only if the target country domain differs from the country domain of origin. By way of example:
Internet addresses are administered by the Network Information Center (NIC) Internet Registry, and are divided into classes, based on the size of the subnetwork. There is currently a great deal of pressure on the addressing scheme, which now supports approximately two million addresses. IP Version 4 (IP4), recently approved, will serve addressing needs into the next century through an expanded address field of 32 bits. IP4, however, does not support advanced functions such as multicasting, resource reservation, and improved security. Another recently approved option, IP6, extends the address field to 128 bits and provides additional functionality, although CPE upgrades are required.
Internet protocols include TCP and IP, as well as application-level protocols. TCP/IP is fundamental to the operation of the Internet, while the application-level protocols serve to support specific user applications.
TCP and IP, as were discussed in Chapter 8, are specific, layered protocols that operate within a protocol stack typically referred to as the TCP/IP protocol suite. TCP/IP is a public domain protocol, because it was developed with public funds for use in a public network, the Internet. The TCP/IP networking protocol suite operates at Layer 3 (Network) and Layer 4 (Transport) of the OSI reference model. TCP/IP has been enhanced continuously and used extensively in all variety of computer networks, including X.25 and Ethernet. Additionally, ISO FTAM, X.400, and X.500 applications protocols (Layer 7) have been layered above TCP/IP by some vendors. The advantages of TCP/IP include its high level of documentation, ease-of-use, stability, and broad applicability. TCP/IP provides a means of passing datagrams between virtually any network capable of sending and receiving bitsit is a highly-effective lowest common denominator protocol.
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