TCP/IP & SOI Layers
The Internet protocol suite is the networking model and a set of communications protocols used for the Internet and similar networks. It is commonly known as TCP/IP, because its most important protocols, the Transmission Control Protocol (TCP) and the Internet Protocol (IP), were the first networking protocols defined in this standard. It is occasionally known as the DoD model, because the development of the networking model was funded by DARPA, an agency of the United States Department of Defense.
TCP/IP provides end-to-end connectivity specifying how data should be formatted, addressed, transmitted, routed and received at the destination. This functionality has been organized into four abstraction layers which are used to sort all related protocols according to the scope of networking involved. From lowest to highest, the layers are the link layer, containing communication technologies for a single network segment (link), theinternet layer, connecting independent networks, thus establishing internetworking, the transport layer handling process-to-process communication, and the application layer, which interfaces to the user and provides support services.
The ISO (International Standards Organization) is a collection of people that are technicians, politicians, lawyers, and members of corporations representing the political / economical / strategic / technical needs of their represented unit. They get together and hammer out standards (not to be confused with protocols) for consistent, international work.
One of their web pages (http://www.iso.ch/iso/en/aboutiso/introduction/index.html)) describes them as:
"The International Organization for Standardization (ISO) is a worldwide federation of national standards bodies from some 130 countries, one from each country.
ISO is a non-governmental organization established in 1947. The mission of ISO is to promote the development of standardization and related activities in the world with a view to facilitating the international exchange of goods and services, and to developing cooperation in the spheres of intellectual, scientific, technological and economic activity.
ISO's work results in international agreements which are published as International Standards. "
The theory and idea behind having standards accepted, ratified, and agreed upon by nations around the world, is to ensure that the system from
Country A will be easily integrated with the system from
Country B with little effort. It also helps to make specification for industries to create goods and services that conform to the standard and by providing competition to the same product, decrease prices for products that must match the minimum standards. Comparisons are made easier in this way for products made by competing groups that must meet or exceed the minimum accepted specified standards.
A protocol is more like a language that can be shared by many people. A protocol may become a standard, if all of the players in the game that would like to use that protocol all politically agree that it shall be the protocol of choice for use in, and between nations. When the protocol is ratified by the governing bodies as the shared and agreed upon system, it becomes an official standard.
A protocol may also become a
de-facto standard or an
informal standard if all players in a game use it without all members officially ratifying the protocol.
Often, a standard attempts to divest itself of being labeled as a protocol and tries to use language to describe how a protocol
may be created to conform to the standard, as in the case of the ISO OSI 7 Layer model.
When two or more parties share a protocol, they have rules that conduct their communications to allow them to share and exchange ideas. For a rough example, we can examine English (the language) and see that two people speaking English with each other must share certain rules. They must have an agreed syntax, speed of speech, and accepted definitions for conveyed words to understand meanings of words stated within their context. Often languages also include systems to recover in the case of errors, and many languages like English also are capable of including rules for correcting for errors. A person may say, "what?" or "could you repeat that?" or even, "do you mean this when you say that?" for some examples.
In this way, you can see that a protocol is merely an agreed upon "language" with agreed upon syntaxes, and definitions used by two or more parties to communicate data or information. When a system or protocol is shared by everyone (or enough of the people that have power, and wield it effective enough to squash or squelch any opposition) then it may also become a standard.
The ISO looked to create a simple model for networking. They took the approach of defining layers that rest in a stack formation, one layer upon the other. Each layer would have a specific function, and deal with a specific task. Much time was spent in creating their model called "
The ISO OSI Seven Layer Model for Networking". In this model, they have 7 layers, and each layer has a special and specific function.
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ISO OSI Seven Layer Model
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WAN
A wide area network (WAN) is a network that covers a broad area (i.e., any telecommunications network that links across metropolitan, regional, or national boundaries) using private or public network transports. Business and government entities utilize WANs to relay data among employees, clients, buyers, and suppliers from various geographical locations. In essence, this mode of telecommunication allows a business to effectively carry out its daily function regardless of location. The Internet can be considered a WAN as well, and is used by businesses, governments, organizations, and individuals for almost any purpose imaginable.
Related terms for other types of networks are personal area networks (PANs), local area networks (LANs), campus area networks (CANs), ormetropolitan area networks (MANs) which are usually limited to a room, building, campus or specific metropolitan area (e.g., a city) respectively.
PPP A
public–private partnership (
PPP) is a government service or private business venture which is funded and operated through a partnership of government and one or more
private sectorcompanies. These schemes are sometimes referred to as PPP, P3 or P
3.
PPP involves a contract between a public sector authority and a private party, in which the private party provides a public service or project and assumes substantial financial, technical and operational risk in the project. In some types of PPP, the cost of using the service is borne exclusively by the users of the service and not by the taxpayer. In other types (notably the private finance initiative), capital investment is made by the private sector on the basis of a contract with government to provide agreed services and the cost of providing the service is borne wholly or in part by the government. Government contributions to a PPP may also be in kind (notably the transfer of existing assets). In projects that are aimed at creating public goods like in the infrastructure sector, the government may provide a capital subsidy in the form of a one-time grant, so as to make it more attractive to the private investors. In some other cases, the government may support the project by providing revenue subsidies, including tax breaks or by removing guaranteed annual revenues for a fixed time period.
There are usually two fundamental drivers for PPPs. Firstly, PPPs enable the public sector to harness the expertise and efficiencies that the private sector can bring to the delivery of certain facilities and services traditionally procured and delivered by the public sector. Secondly, a PPP is structured so that the public sector body seeking to make a capital investment does not incur any borrowing. Rather, the PPP borrowing is incurred by the private sector vehicle implementing the project and therefore, from the public sector's perspective, a PPP is an "off-balance sheet" method of financing the delivery of new or refurbished public sector assets.
Frame Relay is a standardized
wide area network technology that specifies the physical and logical link layers of digital telecommunications channels using a
packet switching methodology. Originally designed for transport across
Integrated Services Digital Network (ISDN) infrastructure, it may be used today in the context of many other network interfaces.
Network providers commonly implement Frame Relay for voice (
VoFR) and data as an
encapsulation technique, used between
local area networks (LANs) over a wide area network (WAN). Each end-user gets a
private line (or
leased line) to a Frame Relay
node. The Frame Relay network handles the transmission over a frequently-changing path transparent to all end-user extensively-used WAN protocols. It is less expensive than leased lines and that is one reason for its popularity. The extreme simplicity of configuring user equipment in a Frame Relay network offers another reason for Frame Relay's popularity.
DNS
The Domain Name System (DNS) is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. Most prominently, it translates easily memorized domain names to the numerical IP addresses needed for the purpose of locating computer services and devices worldwide. The Domain Name System is an essential component of the functionality of the Internet.
An often-used analogy to explain the Domain Name System is that it serves as the phone book for the Internet by translating human-friendly computer hostnames into IP addresses. For example, the domain name www.example.com translates to the addresses 93.184.216.119 (IPv4) and 2606:2800:220:6d:26bf:1447:1097:aa7 (IPv6). Unlike a phone book, the DNS can be quickly updated, allowing a service's location on the network to change without affecting the end users, who continue to use the same host name. Users take advantage of this when they use meaningful Uniform Resource Locators (URLs), and e-mail addresses without having to know how the computer actually locates the services.
The Domain Name System distributes the responsibility of assigning domain names and mapping those names to IP addresses by designating authoritative name servers for each domain. Authoritative name servers are assigned to be responsible for their supported domains, and may delegate authority over subdomains to other name servers. This mechanism provides distributed and fault tolerant service and was designed to avoid the need for a single central database.
The Domain Name System also specifies the technical functionality of this database service. It defines the DNS protocol, a detailed specification of the data structures and data communication exchanges used in DNS, as part of the Internet Protocol Suite.
The Internet maintains two principal namespaces, the domain name hierarchy and the Internet Protocol (IP) address spaces. The Domain Name System maintains the domain name hierarchy and provides translation services between it and the address spaces. Internet name servers and a communication protocol implement the Domain Name System. A DNS name server is a server that stores the DNS records for a domain name, such as address (A or AAAA) records, name server (NS) records, and mail exchanger (MX) records (see also list of DNS record types); a DNS name server responds with answers to queries against its database.
Domain name syntax
The definitive descriptions of the rules for forming domain names appear in RFC 1035, RFC 1123, and RFC 2181. A domain name consists of one or more parts, technically called labels, that are conventionally concatenated, and delimited by dots, such as example.com.
- The right-most label conveys the top-level domain; for example, the domain name www.example.com belongs to the top-level domain com.
- The hierarchy of domains descends from right to left; each label to the left specifies a subdivision, or subdomain of the domain to the right. For example: the label example specifies a subdomain of the com domain, and www is a sub domain of example.com. This tree of subdivisions may have up to 127 levels.
- Each label may contain up to 63 characters. The full domain name may not exceed the length of 253 characters in its textual representation. In the internal binary representation of the DNS the maximum length requires 255 octets of storage, since it also stores the length of the name. In practice, some domain registries may have shorter limits.
- DNS names may technically consist of any character representable in an octet. However, the allowed formulation of domain names in the DNS root zone, and most other sub domains, uses a preferred format and character set. The characters allowed in a label are a subset of the ASCII character set, and includes the characters a through z, Athrough Z, digits 0 through 9, and the hyphen. This rule is known as the LDH rule (letters, digits, hyphen). Domain names are interpreted in case-independent manner.Labels may not start or end with a hyphen. There is an additional rule that essentially requires that top-level domain names not be all-numeric.
- A hostname is a domain name that has at least one IP address associated. For example, the domain names www.example.com and example.com are also hostnames, whereas com is not.
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