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ISO OSI Networking Model
A network model used mostly as a frame of reference to describe and compare other, more widely used networking models (such as TCP/IP, DECNET, FDDI, OSI,
IPX/SPX, DLC and a vast multitude of others), the Open Systems Interconnect (OSI) model is composed of the following layers:
- Application
- Presentation
- Session
- Transport
- Network
- Datalink
- Physical
The following mnemonic phrase should help you remember the layers and their order:"(A)ll (P)eople (S)eem (T)o (N)eed (D)ata (P)rocessing"
NOTE: If you feel you really know the OSI Model, test yourself and see if you are right!
e-commerce (eCommerce) Infrastructure
The sum of policy, planning, hardware and software sufficient to support, produce, present and settle financial transactions online. An element of
financial settlement is the determining factor for eCommerce Infrastructures. For example the aspect of financial settlement separates the Internet into two broad categories; those web sites which play a part
in supporting financial activity (commercial websites) and those which are intended solely to disseminate information (vanity website).
Internet
Web system
Web Server
Web Browser
A specialized program capable of forming connections to Web Servers using the HTTP protocol. A web browser is specifically responsible for rendering
the web server response, which comes in the form of a text file composed of content and markup data. The markup data recognized by the web browser must be either a proprietary extension or that defined as some
version of HTML.
Hyper Text Markup Language (HTML)
Hypertext Transfer Protocol (HTTP)
Secure Hypertext Transfer Protocol (HTTPS)
Web Publishing
Web Programming
Web and Databases
The act of integrating Hyper Text Markup Language (HTML) and a data store - usually through the invocation of an external process (see CGI), though now
many web servers feature "in-process" scripting languages such as Active Server Pages (see ASP) to reduce the inefficiencies implicated in CGI processing
Common Gateway Interface (CGI)
Directory Service System
A means of centrally concentrating information about distributed entities. In the real world, the Telephone Directory assembles contact information
about legal persons (individuals and businesses) in a single, searchable format. On the Internet Directory Services offer similar lookup and contact registration services, as well as many other features
impossible with a physical directory. There are many examples of directory services available, from many different vendors, including Novell (NDS), Microsoft (Active Directory), IBM (X500
), Netscape/AOL/SUN (iPlanet). Most of these products are merely re-branded database products with an Lightweight Directory Access Protocol API in front of them.
Lightweight Directory Access Protocol (LDAP)
LDAP is the means by which processes programmatically access directory servers. In essence a single-focus database Application Programming Interface
(API), LDAP defines the access protocol by which code can request, submit or alter directory information held within a directory server. LDAP is composed of a well-defined set of operations and services to be
revealed by a LDAP compliant server. An extensive set of information on LDAP is available here.
Public Key Infrastructure (PKI)
Many security considerations exist concerning the Internet. PKI is one attempt to create a means of securing transactions that occur over the
Internet by offering a Public Key that can be used to encrypt data meant for a particular recipient. One of the characteristics of a Public Key is that is has a corresponding Private Key which represents the
only means of decrypting the message – the Public Key is a one way mechanism useless for decryption. While Private Keys must be carefully guarded, Public Keys may be freely published on web pages, placed
within directories and as trailers in e-mail addresses. Public Key Infrastructure relates to the services necessary to support such an encryption methodology. One of the most interesting developments in PKI
is the role taken by the National Institute of Standards and Technology (NIST) of the United States. Information on that project is available here.
Extensible Markup Language (XML)
XML is a response to the frustrations of HTML. For businesses, the HTML language came as a mixed blessing. On the one hand, HTML allowed them
to propagate information via the Internet, significantly changing and extending their business processes. On the other hand, HTML was never intended to perform any function other than indicate to the web
browser how information is to be presented, or rendered, on the screen. Realizing that the Internet could also be used to transmit data between computer systems (see EDI), a new language was created to address
this need – XML, a language different from HTML in two significant ways: XML is intimately related to data representation as opposed to presentation, the XML specification is not fixed and can be arbitrarily
extended to meet the evolving needs of those who choose to use it. XML is a fascinating idea with bright promise. More information on XML is available at www.xml.org.
Electronic Data Interchange (EDI)
A carryover from a previous age, EDI was once the dominant means by which computer systems exchanged information. Plagued by problems concerning its
implementation, EDI is nevertheless a significant technology in the sense that it proved that the notion of computers conducting electronic transactions was feasible and achievable. A costly technology, EDI
was responsible for lowering the transaction costs of very large companies such as Sears and Wal*Mart, who could afford the heavy capital cost it represented. Another negative feature of EDI was the many
so-called "standards" that both impeded and raised the costs of implementation. EDI is currently being defined by two
standards bodies - leading to much of the expense and confusion surrounding this rapidly-disinteresting technology, the American National Standards Institute ( ANSI) and the United Nations.
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