Networking Chapter 1

Datagram

A connectionless transfer unit created with User Datagram Protocol designed for quick transfers over a packet-switched network.

Emergency Alert System

A system that typically generates loud noise and flashing lights in response to a fire. The system might also be able to send alert messages to key personnel or make network-wide announcements.

Star Topology

A topology with one central node that has each computer or network device attached to the central node. All data first goes into the central node and then is sent out to its destination. (Think of it like a bicycle wheel with spokes.)

connectionless protocol

A type of Transport layer protocol that services a request without requiring a verified session and without guaranteeing delivery of data.

client-server applications

An application that has two computers. The client computer requests data from the server software on the same or another computer.

connection-oriented protocol

Establishes a network connection, manages the delivery of data, and terminates the connection

NIC (Network Interface Card)

Expansion card on the motherboard that provides a means for network and Internet connections

MAC (Media Access Control) address, physical address, hardware address, or Data Link layer address

Hardware addresses of the source and destination NICS contained in the frame header and is embedded on every network adapter on the globe

SOHO (small office-home office) networks

Less than 10 computers

OSHA (Occupational Safety and Health Administration)

Main federal agency charged with safety and health in the workplace.

TCP (Transmission Control Protocol)

Makes a connection with the end host, checks whether the data is received, and resends it if it is not.

UDP (User Datagram Protocol)

Protocol that operates instead of TCP in applications where delivery speed is important and quality can be sacrificed. Used for broadcasting- such as streaming video or audio over the web

Decapsulation

Removing a header or trailer from a lower OSI layer.

AD DS (Active Directory Domain Services)

The Active Directory service that manages the process that allows a user to sign on to a network from any computer on the network and get access to the resources that Active Directory allows.

port

The Transport layer header addresses the receiving application by a number called a

AD (Active Directory)

The centralized directory database that contains user account information and security for the entire group of computers on a network.

Frame

The entire Data Link layer message, including the header, payload, and trailer.

Session Layer

The fifth layer in the OSI model. Describes how data between applications is synced and recovered if messages don't arrive intact at the receiving application.

Transport Layer

The fourth layer of the OSI model. Responsible for transporting Application layer payloads from one application to another. The two main Transport layer protocols are TCP, which guarantees delivery, and UDP, which does not

IP address

an address assigned to each node on a network, which the Network layer uses to uniquely identify them on the network.

hub

an inefficient and outdated networking device that has been replaced by switches. Accepted signals from a transmitting node and repeated those signals to all other connected nodes in a broadcast fashion.

Physical Layer

The lowest, or first, layer of the OSI model. Responsible only for sending bits via a wired or wireless transmission. These bits can be transmitted as wavelengths in the air (for example, Wi-Fi), voltage on a copper wire (for example, Ethernet on twisted-pair cabling), or light (for example, Ethernet on fiber-optic cabling)

Encapsulation

The process of adding a header to the data inherited from the layer above

scalable

The property of a network that allows you to add nodes or increase its size easily.

network services

The resources a network makes available to its users, including applications and the data provided by these applications.

Data Link Layer

The second layer in the OSI model. Responsible for interfacing with the physical hardware only on the local network.

Application Layer

The seventh layer of the OSI model. The interface between two applications, each on separate computers. Protocols used at this layer {HTTP, SMTP, POP3, IMAP4, FTP, Telnet, and RDP.}

Presentation Layer

The sixth layer of the OSI model. Responsible for reformatting, compressing, and/or encrypting data in a way that the application on the receiving end can read.

packet

The small unit into which information is broken down before being sent across a network.

Network Layer/Internet Layer

The third layer in the OSI model. Responsible for moving messages from one node to another until they reach the destination host

PPE (personal protective equipment)

a barrier between a person and pathogens; includes gloves, gowns, masks, goggles, and face shields

knowledge base

a collection of accumulated insights and solutions to the problems encountered on a particular network.

Grounding

a device is connected directly to the earth, so that, in the event of a short circuit, the electricity flows into the earth, rather than out of control through the device and back to the power station, which can cause an electrical fire.

MSDS (Material Safety Data Sheet)

Standardized form that provides detailed information about potential environmental hazards and proper disposal methods associated with various computing components.

ESD (Electrostatic Discharge)

Static electricity that can build up and discharge causing damage to electronic components. Antistatic devices help prevent _____ damage.

Fail Open

System default that allows access during a system or network failure.

Fail Close

System default that denies access during a system or network failure.

Segments

TCP divides a too large message into smaller messages called

Telnet Protocol

allows an administrator or other user to "remote in" or control a computer remotely.

Host

any computer on a network that hosts a resource such as an application or data

Node

any computer or device on a network that can be addressed on the local network (ex: Switch)

server

any computer or program that provides a service, such as data or other resources, to other devices.

backbone

central conduit that connects the segments (pieces) of a network and is sometimes referred to as "a network of networks."

Header

information in an area at the beginning of the payload that creates a message ready to be transmitted to the Network Layer

switch

receives incoming data from one of its ports and redirects it to another port or multiple ports that will send the data to its intended destination(s).

client-server network model

resources are managed by the NOS via a centralized directory database. The database can be managed by one or more servers, so long as they each have a similar NOS installed.

TCP/IP (Transmission Control Protocol/Internet Protocol)

suite of all the protocols an OS uses for communication on a network

Protocols

technical rules governing data communication

IMAP4 (Internet Message Access Protocol, version 4).

the client application manages the email while it's stored on the server.

API (application programming interface) call

the method an application uses when it makes a request of the OS

P2P (peer-to-peer) network model

the operating system of each computer on the network is responsible for controlling access to its resources without centralized control

HTTP (Hypertext Transfer Protocol)

the primary protocol used for transmitting web pages over the Internet

network operating system (NOS)

controls access to the entire network

Mesh Topology

every computer connects to every other computer; no central connecting device is needed

topology

how the parts of a whole work together.

Firmware

programs embedded into hardware devices. This software does not change unless an upgrade is performed

SNMP (Simple Network Management Protocol)

programs that monitor and gather information about network traffic and can alert network administrators about adverse conditions that need attention

FTP (File Transfer Protocol)

protocol used to upload files from one computer to another and retrieve files from a server to a computer

RDP (Remote Desktop Protocol)

provide secure, encrypted transmissions that allow a technician to remote in—that is, to access a remote computer from the technician's local computer

SSH (Secure Shell Protocol)

used to securely access the console prompt of a remote computer system.

Domain

when a server controls network access to a group of computers

SMTP (Simple Mail Transfer Protocol)

A communications protocol that enables sending email from a client to a server or between servers.

client

A computer that requests data stored on a server.

IP (Internet Protocol)

A connectionless Network-layer protocol that is responsible for sending data packets across a network.

catastrophic failure

A failure that destroys a component beyond use.

star bus topology

A hybrid topology in which groups of workstations are connected in a star fashion to connectivity devices that are networked via a single bus.

OSI (Open Systems Interconnection) reference model

A model for understanding and developing computer-to-computer communication developed in the 1980s by ISO. It divides networking functions among seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

Bus Topology

A network layout in which there is one main trunk, or backbone, that all the various computers and network devices are connected to.

LAN (Local Area Network)

A network of computers and other devices that is confined to a relatively small space, such as one building or even one office.

MAN (Metropolitan Area Network) or CAN (campus area network)

A network that is larger than a LAN, typically connecting clients and servers from multiple buildings, but within a limited geographic area. For example, a ____ could connect multiple city government buildings around a city's center.

WAN (Wide Area Network)

A network that spans a long distance and connects two or more LANs.

PDU (protocol data unit)

A unit of data at any layer of the OSI model.

remote application

An application that is installed and executed on a server, and is presented to a user working at a client computer.

SSL Certificate

An electronic document that confirms the identity of a website or server and verifies that a public key belongs to a trustworthy individual or company

fire suppression system

Any system designed to combat the outbreak of a fire. A ________ might include an emergency alert system, fire extinguishers, emergency power-off switch, and/or a suppression agent such as a foaming chemical or water.

upset failure

Damage that can shorten the life of a component and/or cause intermittent errors.

Payload

Data that is passed between applications or utility programs and the operating system, and includes control information.

Fragmentation

Dividing packets into smaller packets

logical topology

Has to do with software, how access to the network is controlled, including how users and programs initially gain access to the network, and how specific resources, such as applications and databases, are shared on the network.

trip hazard

Items such as extension cords or tools lying on the ground in walkways that can cause someone to stumble.

Remote Desktop Services

Software included in Windows 2008 and later that uses the RDP protocol to present a remote application and its data to the client. Prior to Windows 2008, the software was called Terminal Services.

Hybrid Topology

A physical topology that combines characteristics of more than one simple physical topology.

SFTP (Secure File Transfer Protocol)

A protocol available with the proprietary version of SSH that copies files between hosts securely. Like FTP, SFTP first establishes a connection with a host and then allows a remote user to browse directories, list files, and copy files. Unlike FTP, SFTP encrypts data before transmitting it.

POP3 (Post Office Protocol version 3)

A protocol used from retrieving email from a mailbox on the mail server.

HTTPS (HTTP Secure)

A secure version of HTTP that provides a secure connection between web browser and a server.

TLS (Transport Layer Security)

A security protocol that uses certificates and public key cryptography for mutual authentication and data encryption over a TCP/IP connection.

PAN (Personal Area Network)

A small network consisting of personal devices at close range; the devices can include cell phones, PDAs, and notebook computers.

Trailer

Control information attached to the end of a packet by the Data Link layer protocol.

Ring Topology

Topology where the computers are connected on a loop or ring. Data flows in one direction only.

Router

a device that manages traffic between two or more networks and can help find the best path for traffic to get from one network to another.

Network

a group of computers and other devices (such as printers) that are connected by some type of transmission media.

Physical Topology

a network's hardware and how computers, other devices, and cables fit together to form the physical network.