(pronounced as separate letters) Short for Transmission ControlProtocol/Internet Protocol, the suite of communications protocolsused to connect hosts on the Internet. TCP/IP uses severalprotocols, the two main ones being TCP and IP. TCP/IP is built into the UNIX operating system and is used by the Internet, making it the de facto standard for transmitting data over networks. Evennetwork operating systems that have their own protocols, such as Netware, also supportTCP/IP.
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), the internet 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 TCP/IP model and related protocols are maintained by the Internet Engineering Task Force (IETF).
7 OSI Layers
The Open Systems Interconnection (OSI) model (ISO/IEC 7498-1) is a conceptual model that characterizes and standardizes the internal functions of a communication system by partitioning it into abstraction layers. The model is a product of the Open Systems Interconnection project at the International Organization for Standardization (ISO).
The model groups similar communication functions into one of seven logical layers. A layer serves the layer above it and is served by the layer below it. For example, a layer that provides error-free communications across a network provides the path needed by applications above it, while it calls the next lower layer to send and receive packets that make up the contents of that path. Two instances at one layer are connected by a horizontal connection on that layer.
| Layer # | Name | Mnemonic | Encapsulation Units | Devices or Components | Keywords/Description |
|---|---|---|---|---|---|
| 7 | Application | All | data | PC | Network services for application processes, such as file, print, messaging, database services |
| 6 | Presentation | People | data | Standard interface to data for the application layer. MIME encoding, data encryption, conversion, formatting, compression | |
| 5 | Session | Seem | data | Interhost communication. Establishes, manages and terminates connection between applications | |
| 4 | Transport | To | segments | End-to-end connections and reliability. Segmentation/desegmentation of data in proper sequence. Flow control | |
| 3 | Network | Need | packets | router | Logical addressing and path determination. Routing. Reporting delivery errors |
| 2 | Data Link | Data | frames | bridge, switch, NIC | Physical addressing and access to media. Two sublayers: Logical Link Control (LLC) and Media Access Control (MAC) |
| 1 | Physical | Processing | bits | repeater, hub, transciever | Binary transmission signals and encoding. Layout of pins, voltages, cable specifications, modulation |
WAN Technology
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.[1]
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.
WANs are all about exchanging information across wide geographic areas. They are also, as you can probably gather from reading about the Internet, about scalability—the ability to grow to accommodate the number of users on the network, as well as to accommodate the demands those users place on network facilities. Although the nature of a WAN—a network reliant on communications for covering sometimes vast distances—generally dictates slower throughput, longer delays, and a greater number of errors than typically occur on a LAN, a WAN is also the fastest, most effective means of transferring computer-based information currently available.
PPP
In networking, the Point-to-Point Protocol (PPP) is a data link protocol commonly used in establishing a direct connection between two networking nodes. It can provide connection authentication, transmission encryption (using ECP, RFC 1968), and compression.
PPP is used over many types of physical networks including serial cable, phone line, trunk line, cellular telephone, specialized radio links, and fiber optic links such as SONET. PPP is also used over Internet access connections (now marketed as "broadband"). Internet service providers (ISPs) have used PPP for customer dial-up access to the Internet, since IP packets cannot be transmitted over a modem line on their own, without some data link protocol. Two derivatives of PPP, Point-to-Point Protocol over Ethernet (PPPoE) and Point-to-Point Protocol over ATM (PPPoA), are used most commonly by Internet Service Providers (ISPs) to establish a Digital Subscriber Line (DSL) Internet service connection with customers.
PPP is commonly used as a data link layer protocol for connection over synchronous and asynchronous circuits, where it has largely superseded the older Serial Line Internet Protocol (SLIP) and telephone company mandated standards (such as Link Access Protocol, Balanced (LAPB) in the X.25protocol suite). The only requirement for PPP is that the circuit provided be full duplex. PPP was designed to work with numerous network layerprotocols, including Internet Protocol (IP), TRILL, Novell's Internetwork Packet Exchange (IPX), NBF, DECnet and AppleTalk.
Frame Relay
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.
With the advent of Ethernet over fiber optics, MPLS, VPN and dedicated broadband services such as cable modem and DSL, the end may loom for the Frame Relay protocol and encapsulation.[citation needed] However many rural areas remain lacking DSL and cable modem services. In such cases the least expensive type of non-dial-up connection remains a 64-kbit/s frame-relay line. Thus a retail chain, for instance, may use Frame Relay for connecting rural stores into their corporate WAN.
DNS
(1) Short for Domain Name System (or Service or Server), anInternet service that translates domain names into IP addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address. For example, the domain name www.example.com might translate to198.105.232.4.
The DNS system is, in fact, its own network. If one DNS server doesn't know how to translate a particular domain name, it asks another one, and so on, until the correct IP address is returned.
.ORG
The domain name org is a generic top-level domain (gTLD) of the Domain Name System (DNS) used in the Internet. The name is truncated fromorganization. It was one of the original domains established in 1985 and operated by the Public Interest Registry since 1988. The domain extension was originally created for non-profits, but this designation no longer exists and today it is commonly used by schools, open-source projects, and communities as well as by for-profit entities. The number of registered .org domains has increased from fewer than one million in the 1990s, to ten million as of June, 2012.
.COM
The domain name com is a top-level domain (TLD) in the Domain Name System of the Internet. Its name is derived from the word commercial,[1]indicating its original intended purpose for domains registered by commercial organizations. However, eventually the distinction was lost when .com, .org and .net were opened for unrestricted registration.
The domain was originally administered by the United States Department of Defense, but is today operated by Verisign, and remains under ultimate jurisdiction of U.S. law.[2][3][4] Verisign Registrations in com are processed via registrars accredited by ICANN. The registry acceptsinternationalized domain names.
The domain was one of the original top-level domains (TLDs) in the Internet when the Domain Name System was implemented in January 1985, the others being edu, gov, mil, net, org, and arpa. It has grown into the largest top-level domain.[5]
.GOV
The domain name gov is a sponsored top-level domain (sTLD) in the Domain Name System of the Internet. The name is derived from government, indicating its restricted use by government entities in the United States. The gov domain is administered by the General Services Administration(GSA), an independent agency of the United States federal government.
The U.S. is the only country that has a government-specific top-level domain in addition to its country-code top-level domain. This is a result of the origins of the Internet as a U.S. federal government-sponsored research network (see ARPANET and National Science Foundation Network). Other countries typically delegate a second-level domain for this purpose, for example: .gc.ca is the second-level domain for the Government of Canada and all subdomains.
Some U.S. federal agencies use fed.us rather than gov. The Department of Defense and its subsidiary organizations use the mil sTLD. Some U.S. governmental entities use other domains, such as com domains by the United States Postal Service (which uses both usps.gov andusps.com for the same website, although it only advertises the com address), and the United States Army's recruitment website (goarmy.com, this trend is repeated at the recruitment websites of the other branches of the U.S. military).
All governments in the U.S. are allowed to apply for delegations in gov, such as atlantaga.gov for the city of Atlanta, loudoun.gov for the countyof Loudoun, Virginia and georgia.gov for the U.S. state of Georgia. This was not always true; under an earlier policy, only federal agencies were allowed to use the domain, and agencies beneath cabinet level were required to use subdomains of their parent agency. There is a lack of consistency in addresses of state and local government sites, with some using gov, some us, some using both (the Commonwealth of Pennsylvaniauses www.pa.gov, www.pennsylvania.gov and www.state.pa.us for the same web site) and still others in com, org or other TLDs.
References:
http://www.vlsm-calc.net/models.php
http://www.webopedia.com/TERM/T/TCP_IP.html
http://en.wikipedia.org/wiki/OSI_model
http://en.wikipedia.org/wiki/Internet_protocol_suite
http://en.wikipedia.org/wiki/Wide_area_network
http://en.wikipedia.org/wiki/Point-to-Point_Protocol
http://en.wikipedia.org/wiki/Frame_relay
http://technet.microsoft.com/en-us/library/bb962087.aspx
http://www.webopedia.com/TERM/D/DNS.html
http://en.wikipedia.org/wiki/.org
http://en.wikipedia.org/wiki/.com
http://en.wikipedia.org/wiki/.gov
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