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.