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An Internetwork
An internetwork is simply a network of networks. The networks can be in the same building, on a campus or across the country. They can use the same or different technology. In all cases, however, they need an internetworking device, such as a router or bridge, to propagate the required packets to the other network and a routing protocol to decide which ones need to make the trip.Interconnectivity
Networks are usually homogeneous. They are designed for and owned by one organization. Allowance can be made for the types of machines found on the system and the applications used by its members. Internetworks, however, often connect networks owned by different organizations. Allowing them to communicate with each other requires internetworking devices that can convert the electrical signals from one kind of system to another. Interconnectivity is usually seen as a problem at the physical level of the network.Interoperability
Although an IBM PC and an Apple Macintosh may communicate over the same Ethernet network, will they understand each other? This is a problem in interoperability. It can be related to the transport protocols, the network operating system or even between software applications.Why Computing Standards?
Why have standards?
Some countries require you to drive on the right hand side of the road, some on the left, but never, never is it left up to the individual. Although individual choice is highly desirable in many areas of human activity, there are others in which we must adhere to accepted standards for the common good.Although not all standards concern safety, they can still make life miserable if not adhered to. A famous example was the battle between VHS and Beta to become the standard VCR format. Anyone who had invested in Beta has suffered from its demise.
Market or de facto standards
This type of standard is one that has gained wide acceptance even though it is not mandated. Sometimes it is designed and even owned by one company. Nevertheless, the merits of the standard are great enough that the market has embraced it for its intrinsic value. VHS is a good example of this type of standard. In the data communications field, other examples include Ethernet, SNA, ARCnet and the Hayes AT command set.One major disadvantage of a proprietary standard is that it is under the control of one company. It can be changed without taking into account the needs of other interested parties. Of course, being designed by a committee is not always a great advantage either.
De jure standards
De jure means legislated. In the computer world, it means that a standard was designed by a standards setting body. Since everyone knows the rules and they can’t be changed without the industry voting on it, they are crucial if products are to be designed to work with other vendor’s products.An age old struggle
Companies are always trying to develop proprietary standards which they control. This kind of standard is most valuable if it becomes popular and access can be restricted. Very few companies, typically the largest, can manage to produce such a feat. But it does happen and some examples include IBM’s SNA architecture and the code for the IBM PC BIOS. Access is restricted because the standard is not published, it is difficult to reproduce or the owner is prepared to sue for copyright or patent infringement. An excellent example is Intel pursuing Advanced Micro Devices (AMD) through the courts for many, many years over AMD’s production of 80386 and 80486 microprocessors.Companies that cannot design proprietary standards are interested in open standards. They can then compete on the basis of price and features knowing that their products will work with whatever the customer already has or is going to buy.
Consumers fall into the open standards camp. They want products that are available from multiple vendors, that work with their existing or future equipment and that are well priced. Competition is the key to all of these benefits.Moving from closed to accessible standard
A standard can “open up” in a number of ways.Standards Organizations (or who controls our lives anyway?)
| International Standards Organization (ISO) |
| Open Systems Interconnect (OSI) reference model of networking |
| Institute of Electrical and Electronic Engineers (IEEE) |
| 802.3 committee, governs Ethernet |
| 802.5 committee, governs Token Ring |
| 802.11 committee, governs wireless LANs |
| American National Standards Institute (ANSI) |
| ASCII and ANSI character codes |
| FDDI |
| Comite Consultatif Internationale Telegraphique et Telephonic (CCITT), International Telephone Union (ITU) |
| V series modems, error correcting and compression protocols |
| X series data communication protocols |
| H.323, a Voice over IP protocol |
| Electrical Industry Association (EIA) |
| Cable specs especially 6 categories of unshielded twisted pair cable |
| RS232 |
| Internet Engineering Task Force (IETF) |
| TCP/IP |
| SIP, a Voice over IP protocol |
| All Internet protocols |
| World Wide Web Consortium (W3W) |
| HTML, XML, CSS, DOM |
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