NETWORKING TERMS

2010-01-20T19:43:00.003-08:00

Broadband - A method of transmission in which data flows from source to destination in a different form that existed at the source.
Broadcast - A specially addressed packet that is received by all stations in the same domain.

Dynamic Host Configuration Protocol (DHCP) - A technology allowing TCP/IP address, subnet mask, gateway and other parameters to be assigned to a workstation automatically.

DNS (Domain Name Server) - The DNS is a general purpose distributed, replicated, data query service. The principal use is the lookup of host IP addresses based on host names. The style of host names now used in the Internet is called "domain name", because they are the style of names used to look up anything in the DNS. Some important domains are: .COM (commercial), .EDU (educational), .NET (network operations), .GOV (U.S. government), and .MIL (U.S. military). Most countries also have a domain. For example, .US (United States), .UK (United Kingdom), .AU (

Australia

). It is defined in STD 13, RFCs 1034 and 1035.

DSL (Digital Subscriber Line) - A method for moving data over regular phone lines. A DSL circuit is much faster than a regular phone connection, and the wires coming into the subscriber's premises are the same (copper) wires used for regular phone service. A DSL circuit must be configured to connect two specific locations, similar to a leased line. A commonly discussed configuration of DSL allows downloads at speeds of up to 1.544 megabits (not megabytes) per second, and uploads at speeds of 128 kilobits per second. This arrangement is called ADSL: "Asymmetric" Digital Subscriber Line. Another common configuration is symmetrical: 384 Kilobits per second in both directions. In theory ADSL allows download speeds of up to 9 megabits per second and upload speeds of up to 640 kilobits per second.

DSL is now a popular alternative to Leased Lines and ISDN, being faster than ISDN and less costly than traditional Leased Lines.

Encryption - The process of scrambling data in such a way that it is not readable by anyone except the intended recipient and only after it has been properly decrypted. The means of ensuring that only the entities allowed to see the information packets can see it in an easily accessible format.

Firewall - A system, based on either hardware or software, used to govern traffic between two networks.

Full Duplex - Ability to send traffic in both directions at the same time. WAN links and extended Ethernet can operate this way.

Half Duplex - Communicating in only one direction at a time.

Internet - The worldwide network of networks connected to each other using the TCP/IP protocol suite.

Internet Protocol (IP) - A packet-based protocol used to exchange data over computer networks.

ISDN (Integrated Services Digital Network) - Integrated Services Digital Network. A system that provides simultaneous voice and high-speed data transmission through a single channel to the user's premises. ISDN is an international standard for end-to-end digital transmission of voice, data, and signaling.

Kerberos - A secret key network authentication protocol developed at the Massachusetts Institute of Technology (MIT), using the DES cryptographic algorithm for encryption and a centralized key database for authentication.

LAN - A network system that provides a relatively small area with high-speed data transmission at a low error rate. May include PCs, printers, minicomputers, and mainframes linked by a transmission medium such as a coaxial cable or twisted pair wiring.

MAN Metropolitan Area Network - network that extends over a wider area than a LAN, typically 10-100 Km on a fiber ring.

Network Address Translation (NAT) - The method of converting one IP address to another IP address; primarily used to connect a network which has an internal address space that is on a different standard than another network, such as the Internet.

Node - An addressable device attached to a computer network; also a station, device, or system is used to mean the same thing.

Packet - Also known as a "frame," each packet contains addressing and control information. Packets are variable length, up to a maximum size. Packets for different technologies usually have a minimum and maximum size allowed. For example, Ethernet has a minimum of 64 bytes and a maximum length of 1,500 Bytes. The variable length of frames also means variable delays when traversing a network device.

Ping - A command used to determine the presence and operational nature of another device.

Point-to-Point Protocol (PPP) - A standardized Internet encapsulation of IP over point-to-point links.

Proxy - A device that performs a function on behalf of another device. When referring to firewalls, proxy is a process used to run a number of application checks on the incoming traffic. This process can negatively impact firewall performance.

TCP/IP - The internetworking protocols developed by the

U.S.

government's Advanced Research Project Agency (ARPA). Widely adopted and supported by computer and software manufacturers as a standard computer networking protocol.

Unicast - Transmission across a network addressed to a single node.
Uplink - A high-speed connection for aggregating traffic. For example, a work group switch with several 10 Mbps ports usually will have a 100 Mbps uplink to a backbone switch or a server.

Virtual Private Network (VPN) - Enables IP traffic to possess and ensure secure connectivity over a public TCP/IP network by encrypting all traffic from one network to another. A VPN uses tunneling to encrypt all information at the IP level.

baud

Definition: A baud is a unit of measure for analog signaling. At a minimum, one baud corresponds to one bit per second (bps) although at higher signaling speeds, multiple bits can be transfered in a single baud.

The term baud was popular in the early days of modems, but it is no longer relevant in mainstream computer networking terminology.

Packet Datagram

Definition: A packet is one unit of binary data capable of being routed through a computer network. To improve communication performance and reliability, each message sent between two network devices is often subdivided into packets by the underlying hardware and software.

Depending on the protocol(s) they need to support, packets are constructed in some standard packet format. Packet formats generally include a header, the body containing the message data (also known as the payload), and sometimes a footer (also known as the trailer). The packet header lists the destination of the packet (in IP packets, the destination IP address) and often indicates the length of the message data. The packet footer contains data that signifies the end of the packet, such as a special sequence of bits known as a magic number. Both the packet header and footer may contain error-checking information.
The receiving device is responsible for re-assembling individual packets into the original message, by stripping off the headers and footers and concatenating packets in the correct sequence.

DHCP - Dynamic Host Configuration Protocol

Definition: DHCP allows a computer to join an IP-based network without having a pre-configured IP address. DHCP is a protocol that assigns unique IP addresses to devices, then releases and renews these addresses as devices leave and re-join the network.

Internet Service Providers (ISPs) usually use DHCP to allow customers to join the Internet with minimum effort. Likewise, home network equipment like broadband routers offers DHCP support for added convenience in joining home computers to the LAN.
DHCP environments require a DHCP server set up with the appropriate configuration parameters for the given network. Key DHCP parameters include the range or "pool" of available IP addresses, the correct subnet masks, plus gateway and name server addresses.
Devices running DHCP client software can then automatically retrieve these settings from DHCP servers as needed. Using DHCP on a network means system administrators do not need to configure these parameters individually for each client device.
Dail up

Definition: Dial up networking technology provides PCs and other network devices access to a LAN or WAN via standard telephone lines. Dial up Internet service providers offer subscription plans for home computer users.

Types of dial up services include V.34 and V.90 modem as well as Integrated Services Digital Network (ISDN). Dial up systems utilize special-purpose network protocols like Point-to-Point Protocol (PPP).
To use a dial up Internet connection, a client modem calls another modem located at the Internet Service Provider (ISP). The modems transfer network information over the telephone until one modem or the other disconnects.

DNS - Domain Name System

Definition: The DNS translates Internet domain and host names to IP addresses. DNS automatically converts the names we type in our Web browser address bar to the IP addresses of Web servers hosting those sites.

DNS implements a distributed database to store this name and address information for all public hosts on the Internet. DNS assumes IP addresses do not change (are statically assigned rather than dynamically assigned).

DSL - Digital Subscriber Line

Definition: DSL is a high-speed Internet service like cable Internet. DSL provides high-speed networking over ordinary phone lines using broadband modem technology. DSL technology allows Internet and telephone service to work over the same phone line without requiring customers to disconnect either their voice or Internet connections.

DSL technology theoretically supports data rates of 8.448 Mbps, although typical rates are 1.544 Mbps or lower.
DSL Internet services are used primarily in homes and small businesses. DSL Internet service only works over a limited physical distance and remains unavailable in many areas where the local telephone infrastructure does not support DSL technology.

Also Known As: Digital Subscriber Line, ADSL, SDSL

fiber optic cable

Definition: A fiber optic cable is a network cable that contains strands of glass fibers inside an insulated casing. These cables are designed for long distance and very high bandwidth (gigabit speed) network communications.

firewall

Definition: A network firewall protects a computer network from unauthorized access. Network firewalls may be hardware devices, software programs, or a combination of the two.

FTP

Definition: FTP allows you to transfer files between two computers on the Internet. FTP is a simple network protocol based on Internet Protocol and also a term used when referring to the process of copying files when using FTP technology.

gateway

Definition: A network gateway is an internetworking system capable of joining together two networks that use different base protocols. A network gateway can be implemented completely in software, completely in hardware, or as a combination of both. Depending on the types of protocols they support, network gateways can operate at any level of the OSI model.

Because a network gateway, by definition, appears at the edge of a network, related capabilities like firewalls tend to be integrated with it. On home networks, a broadband router typically serves as the network gateway although ordinary computers can also be configured to perform equivalent functions.

IANA

Definition: IANA is one of the primary governing bodies for Internet networking. IANA oversees three key aspects of the Internet: top-level domains (TLDs), IP address allocation and port number assignments.

top-level domains. Top level domains are the trailing portion of Web domain names such as .com, .org, and .edu.
IP address allocation
TCP and UDP port number assignments

Also Known As: Internet Assigned Numbers Authority

ICMP

Definition: ICMP is a network protocol useful in Internet Protocol (IP) network management and administration. ICMP is a required element of IP implementations. ICMP is a control protocol, meaning that it does not carry application data, but rather information about the status of the network itself. ICMP can be used to report:

errors in the underlying communications of network applications
availability of remote hosts
network congestion

Perhaps the best known example of ICMP in practice is the ping utility, that uses ICMP to probe remote hosts for responsiveness and overall round-trip time of the probe messages. ICMP also supports traceroute, that can identify intermediate "hops" between a given source and destination.

ICS - Internet Connection Sharing

Definition: ICS allows a local network of Windows computers to share a single Internet connection. Microsoft developed ICS as part of Windows 98 Second Edition. The feature has been included as part of all subsequent Windows releases, but it is not available as a separate installable program.

Internet

efinition: The term Internet today refers to the global network of public computers running Internet Protocol. The Internet supports the public WWW and many special-purpose client/server software systems. Internet technology also supports many private corporate intranets and private home LANs.

intranet

Definition: Intranet is the generic term for a collection of private computer networks within an organization. An intranet uses network technologies as a tool to facilitate communication between people or workgroups to improve the data sharing capability and overall knowledge base of an organization's employees.

ISDN - Integrated Services Digital Network

Definition: ISDN is a network technology that supports digital transfer of simultaneous voice and data traffic. Similar to DSL in this respect, an ISDN Internet service works over ordinary telephone lines. ISDN Internet service generally supports data rates of 128 Kbps.

ISP - Internet Service Providers

Definition: An ISP is a company that supplies Internet connectivity to home and business customers. ISPs support one or more forms of Internet access, ranging from traditional modem dial-up to DSL and cable modem broadband service to dedicated T1/T3 lines.

More recently, wireless Internet service providers or WISPs have emerged that offer Internet access through wireless LAN or wireless broadband networks.

LDAP

Definition: LDAP is a standard technology for network directories. Network directories are specialized databases that store information about devices, applications, people and other aspects of a computer network.( Lightweight Directory Access Protocol, Lightweight DAP)

Media Access Control (MAC)

Definition: Media Access Control (MAC) technology provides unique identification and access control for computers on an Internet Protocol (IP) network. In wireless networking, MAC is the radio control protocol on the wireless network adapter. Media Access Control works at the lower sublayer of the data link layer (Layer 2) of the OSI model.

MAC Addresses

Media Access Control assigns a unique number to each IP network adapter called the MAC address. A MAC address is 48 bits long. The MAC address is commonly written as a sequence of 12 hexadecimal digits as follows:

48-3F-0A-91-00-BC

MAC addresses are uniquely set by the network adapter manufacturer and are sometimes called physical addresses. The first six hexadecimal digits of the address correspond to a manufacturer's unique identifier, while the last six digits correspond to the device's serial number. MAC addresses map to logical IP addresses through the Address Resolution Protocol (ARP).

Some Internet service providers track the MAC address of a home router for security purposes. Many routers support a process called cloning that allows the MAC address to be simulated so that it matches one the service provider is expecting. This allows households to change their router (and their real MAC address) without having to notify the provider.

modem

Definition: Traditional modems used in dial-up networking convert data between the analog form used on telephone lines and the digital form used on computers. Standard dial-up network modems transmit data at a maximum rate of 56,000 bits per second (56 Kbps). However, inherent limitations of the public telephone network limit modem speeds to 33.6 Kbps or lower in practice.

NAT - Network Address Translation

Definition: NAT allows an Internet Protocol (IP) network to maintain public IP addresses separately from private IP addresses. NAT is a popular technology for Internet connection sharing. It is also sometimes used in server load balancing applications on corporate networks.

NetMeeting - Microsoft NetMeeting

Definition: NetMeeting is a software application for audio and video conferencing. NetMeeting offers sharing of desktop video, audio, chat and file transfer functionality.

NFS

Definition: A network file system - NFS is a technology for sharing resources between devices on a local area network (LAN). NFS allows data to be stored on central servers and easily accessed from client devices in a client/server network configuration via a process called mounting.

Node

Definition: A node is any device connected to a computer network. Nodes can be computers, personal digital assistants (PDAs), cell phones, or various other network appliances. On an IP network, a node is any device with an IP address.

NIC

Definition: In computer networking, a NIC provides the hardware interface between a computer and a network. A NIC technically is network adapter hardware in the form factor of an add-in card such as a PCI or PCMCIA card.

ping

Definition: Ping is the name of a standard software utility (tool) used to test network connections. It can be used to determine if a remote device (such as Web or game server) can be reached across the network and, if so, the connection's latency. Ping tools are part of Windows, Mac OS X and Linux as well as some routers and game consoles.

Most ping tools use Internet Control Message Protocol (ICMP). They send request messages to a target network address at periodic intervals and measure the time it takes for a response message to arrive. These tools typically support options like

protocol (network)

Definition: A network protocol defines rules and conventions for communication between network devices. Protocols for computer networking all generally use packet switching techniques to send and receive messages in the form of packets.

Proxy Servers

repeater

Definition: Network repeaters regenerate incoming electrical, wireless or optical signals. With physical media like Ethernet or Wi-Fi, data transmissions can only span a limited distance before the quality of the signal degrades. Repeaters attempt to preserve signal integrity and extend the distance over which data can safely travel.

router

Definition: Routers are physical devices that join multiple wired or wireless networks together. Technically, a wired or wireless router is a Layer 3 gateway, meaning that the wired/wireless router connects networks (as gateways do), and that the router operates at the network layer of the OSI model.

server

Definition: A network server is a computer designed to process requests and deliver data to other (client) computers over a local network or the Internet.

Network servers typically are configured with additional processing, memory and storage capacity to handle the load of servicing clients. Common types of network servers include:

Web servers
proxy servers
FTP servers
online game servers

subnet

Definition: A subnet is a logical grouping of connected network devices. Nodes on a subnet tend to be located in close physical proximity to each other on a LAN.

switch (network switch)

Definition: A network switch is a small hardware device that joins multiple computers together within one local area network (LAN). Technically, network switches operate at layer two (Data Link Layer) of the OSI model.

TCP/IP - Transmission Control Protocol / Internet Protocol

Definition: Transmission Control Protocol (TCP) and Internet Protocol (IP) are two distinct network protocols, technically speaking. TCP and IP are so commonly used together, however, that TCP/IP has become standard terminology to refer to either or both of the protocols.

VPN - Virtual Private Network

Definition: A VPN utilizes public telecommunications networks to conduct private data communications. Most VPN implementations use the Internet as the public infrastructure and a variety of specialized protocols to support private communications through the Internet.

workgroup

Definition: In computer networking, a workgroup is a collection of computers on a local area network (LAN) that share common resources and responsibilities. Workgroups provide easy sharing of files, printers and other network resources. Being a peer-to-peer (P2P) network design, each workgroup computer may both share and access resources if configured to do so.

WWW - World Wide Web

Definition: The term WWW refers to the World Wide Web or simply the Web. The World Wide Web consists of all the public Web sites connected to the Internet worldwide, including the client devices (such as computers and cell phones) that access Web content. The WWW is just one of many applications of the Internet and computer networks.

The World Web is based on these technologies:

HTML - Hypertext Markup Language
HTTP - Hypertext Transfer Protocol
Web servers and Web browsers

Researcher Tim Berners-Lee led the development of the original World Wide Web in the late 1980s and early 1990s. He helped build prototypes of the above Web technologies and coined the term WWW. Web sites and Web browsing exploded in popularity during the mid-1990s.

Also Known As: World Wide Web, The Web

MR MOHAN'S NETWORKING