Networking Essentials - M1+M2
Peer-to-Peer Applications
> A ________ allows a device to act as both a client and a server within the same communication. > Every client is a server and every server is a client. > _________ require that each end device provide a user interface and run a background service. In the figure, both clients can simultaneously send and receive messages.
Multiple Roles in the Network
> A computer with server software can provide services simultaneously to one or many clients. > A single computer can run multiple types of server software. > In a home or small business, it may be necessary for one computer to act as a file server, a web server, and an email server.
Internet
> A worldwide collection of interconnected networks, cooperating with each other to exchange information using common standards. > A formless collection of connections. > It is the "place" people go to find or share information. > A network of networks that connects hundreds of millions of computers world-wide.
Wireless Networks - Mobile Telephones
> Can be connected to many different types of networks simultaneously. > These devices use radio waves to transmit voice signals to antennas mounted on towers located in specific geographic areas. > Often referred to as "cell phones" because the geographic area in which an individual tower can provide a signal to a phone is called a cell. When a telephone call is made, the voice signal is relayed from one tower to another tower until it is delivered to its destination. It is also used to send text messages directly from the phone.
Bit
> Computers and networks only work with binary digits, zeros and ones. > Can only have one of two possible values, 0 or 1. > The term is an abbreviation of "binary digit" and represents the smallest piece of data. Humans interpret words and pictures, computers interpret only patterns of these. > Each group of these in eight's is known as a byte.
LAN Components - Network devices
> Connect other devices, mainly hosts. > These devices move and control network traffic. > Examples include hubs, switches, and routers.
Signal
> Consists of electrical or optical patterns that are transmitted from one connected device to another.
LAN Components - Peripherals
> Do not communicate directly on the network. > Rely on their connected host to perform all network operations. > Examples are cameras, scanners, and locally attached printers.
Throughput
> Like bandwidth, this is the measure of the transfer of bits across the media over a given period of time. > This does not usually match the specified bandwidth. > Factors influence this include: - The amount of data being sent and received over the connection - The types of data being transmitted - The latency created by the number of network devices encountered between source and destination
LAN Components - Network media
> Provides connections between hosts and network devices. > Can be wired, such as copper and fiber optic, or use wireless technologies.
Media
> Refers to the physical medium on which the signals are transmitted. Examples of media are copper wire, fiber-optic cable, and electromagnetic waves through the air. > After the data is transformed into a series of bits, it must be converted into signals that can be sent across the network media to its destination.
LAN Components - Hosts
> Send and receive user traffic. \ > A generic name for most end-user devices. > Has an IP address. > Examples are personal computers and network attached printers.
Logical Network Information - Physical Topology
> Shows how network devices connect. > Shows where the wiring is installed and the locations of the networking devices that connect the hosts.
Other Wireless Networks - NFC
> Stands for near field communications. > A wireless communication technology that enables data to be exchanged by devices that are in very close proximity to each other, usually less than a few centimeters.
Wireless Networks - Cell Phone Network
> The abbreviations 3G, 4G, 4G-LTE, and 5G are used to describe these that are optimized for the fast transmission of data. > The "G" in these designations represents the word "generation," so 5G is the fifth generation of the cell network. > The figure shows that 4G will continue to be the dominant source of global mobile traffic in 2022. However, 5G will use an increasingly larger portion.
End Devices / Hosts
> The network devices that people are most familiar with. > These devices form the interface between users and the underlying communication network. - Computers (workstations, laptops, file servers, web servers) - Network printers - Telephones and teleconferencing equipment - Security cameras - Mobile devices (such as smart phones, tablets, PDAs, and wireless debit/credit card readers and barcode scanners)
Network Topologies and Representations
> The physical topology shows where the wiring is installed and the locations of the networking devices that connect the hosts. > These diagrams use symbols or icons to represent the different devices and connections that make up a network.
Peer-to-Peer Networks
> The simplest kind of this network consists of two directly connected computers using either a wired or wireless connection. > In small businesses and homes, many computers function as the servers and clients on the network. Advantages - Easy to set up - Less complex than other networks - Lower cost because network devices and dedicated servers may not be required - Can be used for simple tasks such as transferring files and sharing printers Disadvantages - No central administration - Not as secure as other networks - Not scalable - All devices may act as both clients and server which can slow their performance
> This server runs the email server software. > Clients use mail client software, such as Microsoft Outlook, to access this on the server.
Web
> This server runs web server software. > Clients use browser software, such as Windows Internet Explorer, to access web pages on the server.
File
> This server stores corporate and user files in a central location. > The client devices access these with client software such as the Windows File Explorer.
End Device Addressing
> To physically connect to a network, an end-user device must have a network interface card (NIC) and some configuration of the operating system so that the device can participate in the network. > There are three parts to the IP configuration which must be correct for the device to send and receive information on the network. - IP address - Subnet mask - Default gateway
Other Wireless Networks - Wi-Fi
> Transmitters and receivers located within the smartphone let the phone connect to local networks and the internet. > To receive and send data on a Wi-Fi network, the phone needs to be within the range of the signal from a wireless network access point.
Bandwidth
> Typically measured in the number of bits that (theoretically) can be sent across the media in a second. > Capacity of a medium to carry data. > Digital ________ measures the amount of data that can flow from one place to another in a given amount of time.
Other Wireless Networks - GPS
> Uses satellites to transmit signals that cover the globe. > The smart phone can receive these signals and calculate the phone's location to an accuracy of within 10 meters.
Other Wireless Networks - Bluetooth
> Wireless technology that allows devices to communicate over short distances. > Can be used to transmit both data and voice, it can be used to create small local networks.
Manual and Automatic Address Assignment
> With this configuration, the required values are entered into the device by a network administrator. The IP address that is entered is referred to as a static address and must be unique on the network. > Most end-user devices can be set up to receive network configuration information dynamically. The device requests an address from a pool of addresses assigned by a Dynamic Host Configuration Protocol (DHCP) server located within the network.
Local Network - SOHO (Small Office / Home Office)
Allows computers in a home office or a remote office to connect to a corporate network, or access centralized, shared resources.
Clients
Are computer hosts that have software installed that enables the hosts to request and display the information obtained from the server.
Servers
Are hosts that have software installed which enable them to provide information, like email or web pages, to other hosts on the network.
Connected Home Devices - Smart TV
Can be connected to the internet to access content without the need for TV service provider equipment.
Other Connected Devices - Radio frequency identification (RFIDs) tags
Can be placed in or on objects to track them or monitor sensors for many conditions.
Mobile Devices - Smartwatch
Can connect to a smart phone to provide the user with alerts and messages and other functions, such as heart rate monitoring and counting steps, can help people who are wearing the device to track their health.
Other Connected Devices - Smart Cars
Can connect to the internet to access maps, audio and video content, or information about a destination.
Connected Home Devices - Gaming Consoles
Can connect to the internet to download games and play with friends online.
Other Connected Devices - Connected sensors
Can provide temperature, humidity, wind speed, barometric pressure, and soil moisture data. Actuators can then be automatically triggered based on current conditions.
Clients and Server Roles
Clients are computer hosts that have software installed that enables the hosts to request and display the information obtained from the server. Servers are hosts that have software installed which enable them to provide information, like email or web pages, to other hosts on the network.
Mobile Devices - Smart phones
Combine the functions of many different products together, such as a telephone, camera, GPS receiver, media player, and touch screen computer.
Mobile Devices - Tablets
Come with on-screen keyboards, so users are able to do many of the things they used to do on their laptop computer, such as composing emails or browsing the web.
Local Network - Small home
Connect a few computers to each other and to the internet.
Mobile Devices - Glasses
Contains a tiny screen that displays information to the wearer in a similar fashion to the Head-Up Display (HUD) of a fighter pilot.
Other Connected Devices - Medical Devices
Devices such as pacemakers, insulin pumps, and hospital monitors provide users or medical professionals with direct feedback or alerts when vital signs are at specific levels.
Logical Network Information - Logical Topology
Illustrates the relevant network configuration information.
Connected Home Devices - Connected Security System
Many items in a home, such as lighting and climate controls, can be monitored and configured remotely using a mobile device.
Latency
Refers to the amount of time, including delays, for data to travel from one given point to another.
Connected Home Devices - Household Appliances
Such as refrigerators, ovens, and dishwashers can be connected to the internet.
Network Infrastructure
The network infrastructure contains three categories of hardware components. - End devices - Intermediate devices - Network media
Device Names and Address Planning
The use of logical device naming and addressing conventions that are well documented can greatly simplify the task of training and network management and can help as well with troubleshooting when problems arise.
LAN Components
There are many components that can be part this. Some examples of network components are personal computers, servers, networking devices, and cabling.
End Device Addressing - IP address
This identifies the host on the network.
End Device Addressing - Default gateway
This identifies the networking device that the host uses to access the internet or another remote network.
Types of Data - Observed data
This is captured by recording the actions of individuals, such as location data when using cell phones.
Types of Data - Volunteered data
This is created and explicitly shared by individuals, such as social network profiles. This type of data might include video files, pictures, text or audio files.
Types of Data - Inferred data
This is data such as a credit score, which is based on analysis of volunteered or observed data.
End Device Addressing - Subnet mask
This is used to identify the network on which the host is connected.
Common Methods of Data Transmission - Optical signals
Transmission is achieved by converting the electrical signals into light pulses.
Common Methods of Data Transmission - Electrical signals
Transmission is achieved by representing data as electrical pulses on copper wire.
Common Methods of Data Transmission - Wireless signals
Transmission is achieved by using infrared, microwave, or radio waves through the air.
Volunteered data Observed data Inferred data
Types of Data
Local Network - Medium to Large Networks
Used by corporations and schools, can have many locations with hundreds or thousands of interconnected hosts.
The internet is not owned by any individual or group.
Who owns the internet?