01_Networking Today Flashcards
Hosts
All computers that are connected to a network and participate directly in network communication are classified as hosts. Hosts can be called end devices. Some hosts are also called clients. However, the term hosts specifically refers to devices on the network
Internet Protocol (IP) address
the term hosts specifically refers to devices on the network that are assigned a number for communication purposes. This number identifies the host within a particular network. This number is called the Internet Protocol (IP) address. An IP address identifies the host and the network to which the host is attached.
Servers
Servers are computers with software that allow them to provide information, like email or web pages, to other end devices on the network. Each service requires separate server software. For example, a server requires web server software in order to provide web services to the network. A computer with server software can provide services simultaneously to many different clients.
Common Server Types
TYPE DESCRIPTION
Email The email server runs email server software. Clients use mail client software, such as Microsoft
Outlook, to access email on the server.
Web The web server runs web server software. Clients use browser software, such as Windows Internet Explorer, to access web pages on the server.
File The file server stores corporate and user files in a central location. The client devices access these files with client software such as the Windows File Explorer.
peer-to-peer network
- Client and server software usually run on separate computers, but it is also possible for one computer to be used for both roles at the same time. In small businesses and homes, many computers function as the servers and clients on the network. This type of network is called a peer-to-peer network.
Advantages
- easy to set up
- less complex
- 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 centralized administration
- not as secure
- not as scalable
- all devices act as both clients and servers which can slow their performances
End Devices
The network devices that people are most familiar with are end devices. To distinguish one end device from another, each end device on a network has an address. When an end device initiates communication, it uses the address of the destination end device to specify where to deliver the message.
An end device is either the source or destination of a message transmitted over the network.
Intermediary Devices
intermediary devices connect the individual end devices to the network. They can connect multiple individual networks to form an internetwork. These intermediary devices provide connectivity and ensure that data flows across the network.
Intermediary devices use the destination end device address, in conjunction with information about the network interconnections, to determine the path that messages should take through the network. Examples of the more common intermediary devices and a list of functions are shown in the figure.
Devices include:
- Wireless Router
- Multilayer Switch
- LAN Switch
- Firewall Appliance
- Router
Intermediary network functions:
- regenerate and retransmit communication signals
- maintain information about what pathways exist through the network and internetwork
- Notify other devices of errors and communication failures
- Direct data along alternate pathways when there is a link failure
- Classify and direct messages according to priorities
- Permit or deny the flow of data, based on security settings
Network Media
Communication transmits across a network on media. The media provides the channel over which the message travels from source to destination.
Modern networks primarily use three types of media to interconnect devices, as shown in the figure:
- Metal wires within cables - Data is encoded into electrical impulses.
- Glass or plastic fibers within cables (fiber-optic cable) - Data is encoded into pulses of light.
- Wireless transmission - Data is encoded via modulation of specific frequencies of electromagnetic waves.
Which of the following is the name for all computers connected to a network that participate directly in network communication?
hosts
When data is encoded as pulses of light, which media is being used to transmit the data?
fiber-optic cable
Which two devices are intermediary devices? (Choose two)
routers
switches
Network Interface Card (NIC)
A NIC physically connects the end device to the network.
Physical Port
A connector or outlet on a networking device where the media connects to an end device or another networking device.
The terms port and interface are often used interchangeably.
Interface
Specialized ports on a networking device that connect to individual networks. Because routers connect networks, the ports on a router are referred to as network interfaces.
The terms port and interface are often used interchangeably.
Topology diagrams
mandatory documentation for anyone working with a network. They provide a visual map of how the network is connected. There are two types of topology diagrams: physical and logical.
Physical Topology Diagrams
Physical topology diagrams illustrate the physical location of intermediary devices and cable installation, as shown in the figure. You can see that the rooms in which these devices are located are labeled in this physical topology.
Logical Topology Diagrams
Logical topology diagrams illustrate devices, ports, and the addressing scheme of the network, as shown in the figure. You can see which end devices are connected to which intermediary devices and what media is being used.
Which connection physically connects the end device to the network?
NIC
Which connections are specialized ports on a networking device that connect to individual networks?
Interface
Which type of network topology lets you see which end devices are connected to which intermediary devices and what media is being used?
Logical topology
Which type of network topology lets you see the actual location of intermediary devices and cable installation?
Physical topology
Small Home Networks
Small home networks connect a few computers to each other and to the internet.
Small Office and Home Office Networks
The SOHO network allows computers in a home office or a remote office to connect to a corporate network, or access centralized, shared resources.
Medium to Large Networks
Medium to large networks, such as those used by corporations and schools, can have many locations with hundreds or thousands of interconnected hosts.
World Wide Networks
The internet is a network of networks that connects hundreds of millions of computers world-wide.
Network infrastructures
vary greatly in terms of:
Size of the area covered
Number of users connected
Number and types of services available
Area of responsibility
Local Area Networks (LANs)
LAN is a network infrastructure that provides access to users and end devices in a small geographical area. A LAN is typically used in a department within an enterprise, a home, or a small business network.
LANs have specific characteristics:
- LANs interconnect end devices in a limited area such as a home, school, office building, or campus.
- A LAN is usually administered by a single organization or individual. Administrative control is enforced at the network level and governs the security and access control policies.
- LANs provide high-speed bandwidth to internal end devices and intermediary devices, as shown in the figure.
Wide Area Networks (WANs)
A WAN is a network infrastructure that provides access to other networks over a wide geographical area, which is typically owned and managed by a larger corporation or a telecommunications service provider.
WANs have specific characteristics:
- managed by service providers (SPs) or Internet Service Providers (ISPs)
- WANs interconnect LANs over wide geographical areas such as between cities, states, provinces, countries, or continents.
- WANs are usually administered by multiple service providers.
- WANs typically provide slower speed links between LANs.
The Internet
The internet is a worldwide collection of interconnected networks (internetworks, or internet for short).
Intranet
term often used to refer to a private connection of LANs and WANs that belongs to an organization. An intranet is designed to be accessible only by the organization’s members, employees, or others with authorization.
Extranets
An organization may use an extranet to provide secure and safe access to individuals who work for a different organization but require access to the organization’s data.
Here are some examples of extranets:
- A company that is providing access to outside suppliers and contractors
- A hospital that is providing a booking system to doctors so they can make appointments for their patients
- A local office of education that is providing budget and personnel information to the schools in its district
Which network infrastructure provides access to users and end devices in a small geographical area, which is typically a network in a department in an enterprise, a home, or small business?
LAN
Which network infrastructure might an organization use to provide secure and safe access to individuals who work for a different organization but require access to the organization’s data?
Extranet
Which network infrastructure provides access to other networks over a large geographical area, which is often owned and managed by a telecommunications service provider?
WAN
Cable
Typically offered by cable television service providers, the internet data signal transmits on the same cable that delivers cable television. It provides a high bandwidth, high availability, and an always-on connection to the internet.
DSL
Digital Subscriber Lines also provide high bandwidth, high availability, and an always-on connection to the internet. DSL runs over a telephone line. In general, small office and home office users connect using Asymmetrical DSL (ADSL), which means that the download speed is faster than the upload speed.
Cellular
Cellular internet access uses a cell phone network to connect. Wherever you can get a cellular signal, you can get cellular internet access. Performance is limited by the capabilities of the phone and the cell tower to which it is connected.
Satellite
The availability of satellite internet access is a benefit in those areas that would otherwise have no internet connectivity at all. Satellite dishes require a clear line of sight to the satellite.
Dial-up Telephone
An inexpensive option that uses any phone line and a modem. The low bandwidth provided by a dial-up modem connection is not sufficient for large data transfer, although it is useful for mobile access while traveling.
Dedicated Leased Line
Leased lines are reserved circuits within the service provider’s network that connect geographically separated offices for private voice and/or data networking. The circuits are rented at a monthly or yearly rate.
Metro Ethernet
This is sometimes known as Ethernet WAN. In this module, we will refer to it as Metro Ethernet. Metro ethernets extend LAN access technology into the WAN. Ethernet is a LAN technology you will learn about in a later module.
Business DSL
Business DSL is available in various formats. A popular choice is Symmetric Digital Subscriber Line (SDSL) which is similar to the consumer version of DSL but provides uploads and downloads at the same high speeds.
Satellite
Satellite service can provide a connection when a wired solution is not available.
Converged Networks
converged networks are capable of delivering data, voice, and video between many different types of devices over the same network infrastructure. This network infrastructure uses the same set of rules, agreements, and implementation standards. Converged data networks carry multiple services on one network.
Packet Tracer
a tool that allows you to simulate real networks. It provides three main menus:
- You can add devices and connect them via cables or wireless.
- You can select, delete, inspect, label, and group components within your network.
- You can manage your network by opening an existing/sample network, saving your current network, and modifying your user profile or preferences.
basic characteristics that network architects must address to meet user expectations
- Fault Tolerance
- Scalability
- Quality of Service (QoS)
- Security
Fault Tolerance
A fault tolerant network is one that limits the number of affected devices during a failure. It is built to allow quick recovery when such a failure occurs. These networks depend on multiple paths between the source and destination of a message. If one path fails, the messages are instantly sent over a different link. Having multiple paths to a destination is known as redundancy.
Implementing a packet-switched network is one way that reliable networks provide redundancy. Packet switching splits traffic into packets that are routed over a shared network. A single message, such as an email or a video stream, is broken into multiple message blocks, called packets. Each packet has the necessary addressing information of the source and destination of the message. The routers within the network switch the packets based on the condition of the network at that moment. This means that all the packets in a single message could take very different paths to the same destination. In the figure, the user is unaware and unaffected by the router that is dynamically changing the route when a link fails.
Scalability
A scalable network expands quickly to support new users and applications. It does this without degrading the performance of services that are being accessed by existing users. The figure shows how a new network is easily added to an existing network. These networks are scalable because the designers follow accepted standards and protocols. This lets software and hardware vendors focus on improving products and services without having to design a new set of rules for operating within the network.
Quality of Service
quality of Service (QoS) is an increasing requirement of networks today.
Congestion occurs when the demand for bandwidth exceeds the amount available. Network bandwidth is measured in the number of bits that can be transmitted in a single second, or bits per second (bps). When simultaneous communications are attempted across the network, the demand for network bandwidth can exceed its availability, creating network congestion.
With a QoS policy in place, the router can manage the flow of data and voice traffic, giving priority to voice communications if the network experiences congestion. The focus of QoS is to prioritize time-sensitive traffic. The type of traffic, not the content of the traffic, is what is important.
Network Security
The network infrastructure, services, and the data contained on network-attached devices are crucial personal and business assets. Network administrators must address two types of network security concerns: network infrastructure security and information security.
- Confidentiality - Data confidentiality means that only the intended and authorized recipients can access and read data.
- Integrity - Data integrity assures users that the information has not been altered in transmission, from origin to destination.
- Availability - Data availability assures users of timely and reliable access to data services for authorized users.
When designers follow accepted standards and protocols, which of the four basic characteristics of network architecture is achieved?
Scalability
Confidentiality, integrity, and availability are requirements of which of the four basic characteristics of network architecture?
Security
With which type of policy, a router can manage the flow of data and voice traffic, giving priority to voice communications if the network experiences congestion?
QoS
Having multiple paths to a destination is known as redundancy. This is an example of which characteristic of network architecture?
fault tolerance
Bring Your Own Device (BYOD)
BYOD means any device, with any ownership, used anywhere.
Online Collaboration
Collaboration is a critical and strategic priority that organizations are using to remain competitive. Collaboration is also a priority in education.
Video Communications
Another facet of networking that is critical to the communication and collaboration effort is video. Video is used for communications, collaboration, and entertainment. Video calls are made to and from anyone with an internet connection, regardless of where they are located.
Video conferencing is a powerful tool for communicating with others, both locally and globally. Video is becoming a critical requirement for effective collaboration as organizations extend across geographic and cultural boundaries.
Cloud Computing
Cloud computing is one of the ways that we access and store data. Cloud computing allows us to store personal files, even backup an entire drive on servers over the internet. Applications such as word processing and photo editing can be accessed using the cloud.
Cloud computing is possible because of data centers. Data centers are facilities used to house computer systems and associated components. A data center can occupy one room of a building, one or more floors, or an entire warehouse-sized building. Data centers are typically very expensive to build and maintain.
Cloud Types
Public clouds
Cloud-based applications and services offered in a public cloud are made available to the general population. Services may be free or are offered on a pay-per-use model, such as paying for online storage. The public cloud uses the internet to provide services.
Private clouds
Cloud-based applications and services offered in a private cloud are intended for a specific organization or entity, such as a government. A private cloud can be set up using the organization’s private network, though this can be expensive to build and maintain. A private cloud can also be managed by an outside organization with strict access security.
Hybrid clouds
A hybrid cloud is made up of two or more clouds (example: part private, part public), where each part remains a distinct object, but both are connected using a single architecture. Individuals on a hybrid cloud would be able to have degrees of access to various services based on user access rights.
Community clouds
A community cloud is created for exclusive use by specific entities or organizations. The differences between public clouds and community clouds are the functional needs that have been customized for the community. For example, healthcare organizations must remain compliant with policies and laws (e.g., HIPAA) that require special authentication and confidentiality. Community clouds are used by multiple organizations that have similar needs and concerns. Community clouds are similar to a public cloud environment, but with set levels of security, privacy, and even regulatory compliance of a private cloud.
Smart home technology
Smart home technology integrates into every-day appliances, which can then connect with other devices to make the appliances more ‘smart’ or automated.
Powerline Networking
Powerline networking for home networks uses existing electrical wiring to connect devices
Using a standard powerline adapter, devices can connect to the LAN wherever there is an electrical outlet. No data cables need to be installed, and there is little to no additional electricity used. Using the same wiring that delivers electricity, powerline networking sends information by sending data on certain frequencies.
Powerline networking is especially useful when wireless access points cannot reach all the devices in the home. Powerline networking is not a substitute for dedicated cabling in data networks. However, it is an alternative when data network cables or wireless communications are not possible or effective.
Wireless Internet Service Provider (WISP)
Wireless Internet Service Provider (WISP) is an ISP that connects subscribers to a designated access point or hot spot using similar wireless technologies found in home wireless local area networks (WLANs). WISPs are more commonly found in rural environments where DSL or cable services are not available.
Wireless Broadband Service
Another wireless solution for the home and small businesses is wireless broadband
Which feature is a good conferencing tool to use with others who are located elsewhere in your city, or even in another country?
Video communications
Which feature describes using personal tools to access information and communicate across a business or campus network?
BYOD
Which feature contains options such as Public, Private, Custom and Hybrid?
Cloud commuting
Which feature is being used when connecting a device to the network using an electrical outlet?
Powerline
Which feature uses the same cellular technology as a smart phone?
Wireless broadband
Viruses, worms, and Trojan horses
These contain malicious software or code running on a user device
Spyware and adware
These are types of software which are installed on a user’s device. The software then secretly collects information about the user
Zero-day attacks
Also called zero-hour attacks, these occur on the first day that a vulnerability becomes known
Threat actor attacks
A malicious person attacks user devices or network resources
Denial of service attacks
These attacks slow or crash applications and processes on a network device
Data interception and theft
This attack captures private information from an organization’s network
Identity theft
This attack steals the login credentials of a user in order to access private data
Antivirus and antispyware
These applications help to protect end devices from becoming infected with malicious software
Firewall filtering
Firewall filtering blocks unauthorized access into and out of the network. This may include a host-based firewall system that prevents unauthorized access to the end device, or a basic filtering service on the home router to prevent unauthorized access from the outside world into the network
Dedicated firewall systems
These provide more advanced firewall capabilities that can filter large amounts of traffic with more granularity
Access control lists (ACL)
These further filter access and traffic forwarding based on IP addresses and applications
Intrusion prevention systems (IPS)
These identify fast-spreading threats, such as zero-day or zero-hour attacks
Virtual private networks (VPN)
These provide secure access into an organization for remote workers
Which attack slows down or crashes equipment and programs?
Denial of Service (DoS)
Which option creates a secure connection for remote workers?
Virtual Private Network (VPN)
Which option blocks unauthorized access to your network?
Firewall
Which option describes a network attack that occurs on the first day that a vulnerability becomes known?
Zero-day or Zero-hour
Which option describes malicious code running on user devices?
Virus, worm, or Trojan horse
During a routine inspection, a technician discovered that software that was installed on a computer was secretly collecting data about websites that were visited by users of the computer. Which type of threat is affecting this computer?
spyware
Which term refers to a network that provides secure access to the corporate offices by suppliers, customers and collaborators?
extranet
A large corporation has modified its network to allow users to access network resources from their personal laptops and smart phones. Which networking trend does this describe?
bring your own device
What is an ISP?
It is an organization that enables individuals and businesses to connect to the Internet
In which scenario would the use of a WISP be recommended?
a farm in a rural area without wired broadband access
What characteristic of a network enables it to quickly grow to support new users and applications without impacting the performance of the service being delivered to existing users?
scalability
A college is building a new dormitory on its campus. Workers are digging in the ground to install a new water pipe for the dormitory. A worker accidentally damages a fiber optic cable that connects two of the existing dormitories to the campus data center. Although the cable has been cut, students in the dormitories only experience a very short interruption of network services. What characteristic of the network is shown here?
fault tolerance
What are two characteristics of a scalable network? (Choose two.)
- grows in size without impacting existing users
- suitable for modular devices
Which device performs the function of determining the path that messages should take through internetworks?
a router
Which two Internet connection options do not require that physical cables be run to the building? (Choose two.)
- cellular
- satellite
What type of network must a home user access in order to do online shopping?
Internet
How does BYOD change the way in which businesses implement networks?
BYOD provides flexibility in where and how users can access network resources
An employee wants to access the network of the organization remotely, in the safest possible way. What network feature would allow an employee to gain secure remote access to a company network?
VPN
What is the Internet?
It provides connections through interconnected global networks
What are two functions of end devices on a network?
- they are the interface between humans and the communication network
- they originate the data that flows through the network
