Network+ Ch. 1 Terms

Topology All devices connect to one central device, the switch.

Star Topology

An example of this topology would be 3 switches daisy-chained together in a single line. Each switch is also connected to multiple computers.

Star-Bus Topology

This can consist of a foaming chemical, gas, or water that sprays everywhere to put out the fire.

Suppression Agent

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

Switch

Protocols that operate at OSI Layer 4.

TCP & UDP

Makes a connection with the end host, checks whether the data is received, and resends it if it is not. Called a connection-oriented protocol. Guaranteed delivery takes longer and is used when it is important to know that the data reached its destination.

TCP (Transmission Control Protocol)

The two primary protocols.

TCP (Transmission Control Protocol) & IP (Internet Protocol)

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

TCP/IP

A four-layer model similar to the OSI model. Application, Presentation, and Session layers are wrapped together and are called the Application layer. The Physical layer is so simple, it's ignored, which makes for four layers: Application layer, Transport layer, Internet layer (Network layer in OSI), and Link layer (Data Link layer in the OSI).

TCP/IP model

Commandline application to allow an administrator or other user to "remote in" or control a computer remotely. Included in many operating systems, but not encrypted. Replaced by SSH.

Telnet

Does not guarantee delivery by first connecting and checking whether data is received. Called a connectionless protocol or best-effort protocol. Used for broadcasting, such as streaming video or audio over the web, where guaranteed delivery is not as important as fast transmission. Also used to monitor network traffic.

UDP (User Datagram Protocol)

Static electricity can cause two types of damage in an electronic component. This type shortens the life of a component and/or cause intermittent errors.

Upset Failure

Advantages of a Client-Server Networks.

User accounts & passwords stored in one place, access to multiple shared resources, monitoring of problems & fixed from one location, more scalable

Step 6 of the CompTIA troubleshooting steps.

Verify functionality and implement preventive measures

A group of LANs that spread over a wide geographical area.

WAN (wide area network)

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

AD (Active Directory)

A user can sign on to the network from any computer on the network and get access to the resources that Active Directory allows.

AD DS (Active Directory Domain Services)

Method an application uses when it makes a request of the OS.

API (application programming interface) call

Seven-Word mnemonic to remember the OSI Model.

All People Seem To Need Data Processing

The most popular web server application.

Apache

OSI Layer 7. Describes the interface between two applications, each on separate computers. This is the layer we see.

Application layer

Is a central conduit that connects the segments of a network and is sometimes referred to as "a network of networks." Might use higher transmission speeds and different cabling than network cables connected to computers because of the heavier traffic and the longer distances it might span.

Backbone

OSI Layer 2. Responsible for interfacing with the physical hardware only on the local network. Simple switches operate on this layer.

Data Link Layer

If the message is too large to transport on the network, UDP divides it into smaller messages called this.

Datagram

Process of removing a header and trailer from a lower layer's PDU.

Decapsulation

Step 7 of the CompTIA troubleshooting steps.

Document findings, actions, and outcomes

In addition, sensitive electronic components (for example, a NIC, motherboard, and memory modules) can be damaged by this. Commonly known as static electricity. Static electricity is an electrical charge at rest.

ESD (electrostatic discharge)

Protective gear you wear on your wrist that you clip to the chassis, or PC case, which eliminates any ESD between you and the chassis and it's components.

ESD strap

These systems vary, but they typically generate loud noise and flashing lights. Some send text and voice message alerts to key personnel, and post alerts by email, network messages, and other means.

Emergency Alert System

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

Encapsulation

Step 4 of the CompTIA troubleshooting steps.

Establish a plan for resolving the problem

Step 2 of the CompTIA troubleshooting steps.

Establish a theory of probable cause

Protocols that operate at OSI Layer 1 and 2.

Ethernet & Wi-Fi

Examples of Data Link layer protocols.

Ethernet & WiFi

A client-server application that transfers files between two computers uses this protocol. It is not secure.

FTP (File Transfer Protocol)

If firewall software protecting access to a database of customer credit card numbers fails, it might be configured to this policy and to deny access to the database until the software is back online.

Fail-Close

During a fire alert, using this policy, all exit doors stay unlocked so that people can safely leave the building and firefighters can enter the building, even though this might present a security risk for thieves entering the building.

Fail-Open

Examples of dedicated FTP clients.

FileZilla and CuteFTP

A company is likely to have this in it's data center.

Fire Suppression System

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

Firmware

If a Network layer protocol is aware that a packet is larger than the maximum size for its network, it will divide the packet into smaller packets in this process.

Fragmentation

A switch belongs only to its local network and a router belongs to two or more local networks.

Fundamental difference between a switch and a router.

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.

Grounding

The primary protocol used by web servers and browsers (clients).

HTTP (Hypertext Transfer Protocol)

9 examples of protocols that operate at OSI Layer 5, 6 & 7.

HTTP, HTTPS, SMTP, POP3, IMAP4, FTP, FTPS, RDP, Telnet

Used by web servers and browsers (Clients) and gives a secure transmission.

HTTPS (HTTP Secure)

The TCP & UDP protocols add their own control information in an area at the beginning of the payload.

Header

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

Host

Legacy technology, switches replaced this. Accepted signals from a transmitting node and repeated those signals to all other connected nodes in a broadcast fashion.

Hub

A topology that combines topologies.

Hybrid Topology

IP relies on several supporting protocols to find the best route for a packet when traversing several networks on its way to its destination. These are two of them.

ICMP (Internet Control Message Protocol) and ARP (Address Resolution Protocol)

Second most popular web server application, which is embedded in the Windows Server OS.

IIS

The principal protocol used by the Network layer.

IP (Internet Protocol)

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

IP Address

Protocols that operate at OSI Layer 3.

IP, ICMP & ARP

Each node on the network can communicate directly with others on the network. Usually contained in a small space, such as an office or building.

LAN (local area network)

This printer connects directly to a computer on the network.

Local Printer

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.

Logical Topology

The frame header contains the hardware address of the source and destination NICs. This address is embedded on every network adapter on the globe. The physical addresses are short-range addresses that can only find nodes on the local network.

MAC (Media Access Control) Address

A group of connected LANs in the same geographical area—for example, a handful of government offices surrounding a state capitol building

MAN (metropolitan area network) or CAN (campus area network)

Also called an SDS (safety data sheet), explains how to properly handle substances such as chemical solvents and how to dispose of them.

MSDS (Material Safety Data Sheet)

Topology where each device connects to multiple other devices.

Mesh Topology

Where you plug a network cable. This adapter is installed in an expansion slot on the motherboard. Uses the PCIe x1 slot.

NIC (network interface card)

Client-server model requires one or more of these. They control access to the entire network. Examples are Windows Server 2016, Ubuntu Server, and Red Hat Enterprise Linux.

NOSes (network operating systems)

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

Network

OSI Layer 3. Responsible for moving messages from one node to another until they reach the destination host.

Network Layer

This Printer has a network port and connects directly to the switch.

Network Printer

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

Network Services

Any computer or device on a network that can be addressed on the local network. Routers and Switches can only be these.

Node

Disadvantages of using traditional peer-to-peer networks.

Not scalable, not as secure & not practical for more than a few PCs

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

OSHA (Occupational Safety and Health Administration)

Made Early in the evolution of networking, a 7-layer model was developed to categorize the layers of communication. It was first developed by the International Organization for Standardization, also called the ISO.

OSI (Open Systems Interconnection)

If the network supports fewer than 15 computers this network model is the way to go.

P2P (peer-to-peer)

No computer has more authority than another; each computer controls its own resources, and communicates directly with other computers.

P2P (peer-to-peer) network model

The smallest network. Network of personal devices, such as the network you use when you sync your smartphone and your computer.

PAN (personal area network)

There are several different names for a group of bits as it moves from one layer to the next and from one LAN to the next. Although technicians loosely call this group of bits a message or a transmission this is the technical name.

PDU (protocol data unit)

The recipient's mail server delivers the message to the receiving client using these two protocols.

POP3 (Post Office Protocol, version 3) & IMAP4 (Internet Message Access Protocol, version 4)

Wear this to protect yourself as you work. For example, wear eye protection where dust or fumes are generated by power tools.

PPE (personal protective equipment)

IP adds its own Network layer header to the segment or datagram, and the entire Network layer message is called this.

Packet

PDU name that operates at layers 5, 6 & 7. Data that is passed between applications or utility programs and the operating system and includes control information.

Payload

OSI Layer 1. Simplest layer of all and is responsible only for sending bits via a wired or wireless transmission. These bits can be transmitted as wavelengths in the air, voltage on a copper wire (for example, Ethernet on twisted-pair cabling), or light (for example, Ethernet on fiber-optic cabling).

Physical Layer

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

Physical Topology

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

Port

OSI Layer 6. Responsible for reformatting, compressing, and/or encrypting data in a way that the application on the receiving end can read.

Presentation Layer

Networked devices use these methods and rules for communication.

Protocols

Windows Server 2008 and later versions include this to manage remote applications, and versions of Windows Server prior to 2008 provided Terminal Services.

RDP (Remote Desktop Protocol)

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

Remote Application

Nodes are connected in a ring, with one node connecting only to its two neighboring nodes. A node can put data on the ring only when it holds a token, which is a small group of bits passed around the ring. This is similar to saying "I hold the token, so I get to talk now." This topology is rarely used today, because of its slow speed.

Ring Topology

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.

Router

Encrypted and secure file transfer protocol.

SFTP (Secure File Transfer Protocol)

The client uses this protocol to send an email message to the first server.

SMTP (Simple Mail Transfer Protocol)

Utility programs that provide services to the system. Monitors and gathers information about network traffic and can alert network administrators about adverse conditions that need attention

SNMP (Simple Network Management Protocol)

Acronym for a smaller network used in small office and home networks.

SOHO (Small office-home office)

This command in Linux creates a secure channel or tunnel between two computers. Replaced Telnet.

SSH (Secure Shell)

HTTP is layered on top of these encryption protocols and the result is HTTPS (HTTP Secure)

SSL (Secure Sockets Layer) & TLS (Transport Layer Security)

If the message is too large to transport on the network, TCP divides it into smaller messages called this.

Segments

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

Server

OSI Layer 5. Describes how data between applications is synced and recovered if messages don't arrive intact at the receiving application.

Session Layer

Advantages of using peer-to-peer networks.

Simple to configure & Less expensive and maintain

When your body and a component have different static charges and you touch the component, you can discharge up to 1,500 volts of static electricity without seeing a spark or feeling the discharge. However, it only takes this ammount to damage the component.

10 volts

Static electricity can cause two types of damage in an electronic component. This type destroys the component beyond use.

Catastrophic Failure

Fire extinguishers need to be this class to put out electrical fires.

Class C

A computer making a request from another.

Client

These applications, which involve two computers. The first computer, a client computer, requests data or a service from the second computer, which is the server.

Client-Server Applications

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.

Client-Server Network Model

Both a router and a switch, and maybe a wireless access point. The home router belongs to the home's local network on one side and the ISP's local network on the other. Not to be confused with a dedicated router.

Combo Device

Step 1 of the CompTIA troubleshooting steps.

Identify the problem and its symptoms

Step 5 of the CompTIA troubleshooting steps.

Implement the solution or escalate the problem

Step 3 of the CompTIA troubleshooting steps.

Test your theory to determine the cause

Describes how the parts of a whole network work together.

Topology

The Data Link layer puts its own control information in a Data Link layer header and also attaches control information to the end of the packet called this.

Trailer

OSI Layer 4. Responsible for transporting Application layer payloads from one application to another. The two main protocols are TCP & UDP.

Transport Layer

When Windows Server controls network access to a group of computers, this logical group is called this.

Windows Domain

If all computers in a peer-to-peer network are running a Windows operating system, resources can be shared in these ways:

Workgroup & Windows folder and file sharing & homegroups