Internet Protocol address (IP address) - An address that identifies the network and host address assigned to a device.

Subnet address - The portion of the IP address that identifies the network the device is assigned to.

Local area network - (LAN) - A group of computers and associated devices that share a common communications line or wireless link, typically to a server.

Metropolitan area network - (MAN) - Computer users and resources within a geographic area the size of a metropolitan area that is connected.

Wide area network - (WAN) - A network that connects several LANs. WANs are often limited to a corporation or an organization but are sometimes accessible to the public.

Software-defined wide area network - (SDWAN) - A WAN that uses software to control connectivity.

Multi-point Generic Routing Encapsulation - (mGRE) - A tunnel interface.

Internet - A collection of many networks owned by many entities that share information and communicate together.

Intranet - A local or restricted communications network, especially a private network created using World Wide Web software.

Extranet - An intranet that can be partially accessed by authorized outside users, enabling businesses to exchange information over the internet securely.

Topology - The term used to describe how devices are connected and how messages flow from device to device. The physical topology describes the way the network is wired. The logical topology describes the way they send messages.

Terminator - A device that is connected to absorb signals and prevent them from reflecting repeatedly back and forth on the cable. We use terminators with bus topology.

Host role's

​Peer-to-peer - In a peer-to-peer network, each host can provide network resources or use resources on other hosts. Each host providing resources controls access to the resources.

Advantages of peer-to-peer networks include:

• Easy implementation

• Inexpensive

Disadvantages of peer-to-peer networks include:​

• Difficult to expand (not scalable)

• Difficult to support

• Lack of centralized control

• No centralized storage

Client-server - In a client-server network, hosts have specific roles. For example, we assign some hosts server roles that allow them to provide network resources to other hosts. We assign other hosts client roles that allow them to consume network resources.

Advantages of client-server networks include:

• Easy to expand (scalable)

• Easy to support

• Centralized services

• Easy to back up

​Disadvantages of client-server networks include:

• Expensive server operating systems

• Extensive advanced planning required

​Geography

Personal area network (PAN) - A private area network is a small network used for communicating between personal devices. For example, a PAN may include a notebook computer, a wireless headset, a wireless printer, and a smartphone.
A PAN is limited in range to only a few feet. We typically create a PAN using Bluetooth wireless technologies.

Local area network (LAN) - A local area network is a network in a small geographic area, like an office. A LAN typically uses wires to connect systems together.

Wireless local area network (WLAN) - A wireless LAN covers an area that is roughly the same size as a standard LAN. However, it uses radio signals instead of wires to connect systems together.

Wireless local area network (WLAN) - A wireless LAN covers an area that is roughly the same size as a standard LAN. However, it uses radio signals instead of wires to connect systems together.

Wide area network (WAN) - A wide area network is a group of LANs that are geographically isolated and connected to form a large inter-network.

Metropolitan area network (MAN) - A metropolitan area network is a network that covers an area as small as a few city blocks to as large as an entire metropolitan city. MANs are typically owned and managed by a city as a public utility.
Be aware that many IT professionals do not differentiate between a wide area network and a MAN, as they use the same network technologies.

Campus area network (CAN) - A campus area network is a computer network made up of an interconnection of local area networks within a limited geographical area, such as a university's campus.
Most of the networking components, such as the transmission media, switches, and routers are owned by the campus tenant.

Software-defined wide area network (SD-WAN)

SD-WAN - 

• A software-defined wide area network is a virtual WAN network that uses software to control connectivity, management, and services between data centers and remote branches, and the cloud.

• It allows any combination of transport services such as Long Term Evolution (LTE), Multi-protocol Label Switching (MPLS), and broadband internet services, to securely connect users to applications.

• SD-WAN is based on the same method as software-defined networking (SDN) which separates the control plane from the data plane to make networking more intelligent.

Management

Network 

• The term network often describes a computer system controlled by a single organization. This could be a local area network at a single location or a wide area network used by a single business or organization.

• If two companies connect their internal networks to share data, you could call it one network. However, it is two networks because a different company manages each network.

Subnet - A subnet is a portion of a network with a common network address.​

• All devices on the subnet share the same network address, but they have unique host addresses.

• Each subnet in a larger network has a unique subnet address.

• Devices connected through hubs or switches are on the same subnet. Routers are used to connect multiple subnets.

Internetwork​

• An inter-network has geographically dispersed WAN connections that connect multiple LANs.

• Connecting two networks under different management is a form of inter-networking because data must travel between two networks.

​Participation

Internet

The internet is a large worldwide public network. The internet is public because virtually anyone can connect to it.

• Users and organizations connect to the internet through an internet service provider (ISP).

• The internet uses a set of communication protocols (TCP/IP) for providing services.

• Individuals and organizations can make services (such as a website) available to other users on the internet.

Intranet

• An intranet is a private network that uses internet technologies. Services on an intranet are available only to hosts that are connected to the private network.

• For example, your company might have a website that only employees can access.

Extranet

• An extranet is a private network that uses internet technologies, but it makes its resources available only to external, trusted users.

• For example, you might create a website on a private network that only users from a partner company can access.
   

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