Computer Network Terminology and Basic Concepts

In this post, I’m going to list and explain the most commonly used computer networking terms and technologies.

If you are new to computer networking, this will be a great resource for you to get familiar with the basic network terminology used in enterprise networks.

I’ve grouped the terms into different sections to make them easier to understand and reference. Some terms can be very technical, I’ve provided a short and easy explanation for each term.

Basic Networking Terms

These are basic network terms you should be familiar with when managing a network.

ACL (Access Control List)

An Access Control List (ACL) contains rules dictating which IP or subnets have access to a system resource or computer system component. An ACL acts as a traffic filter, determining which IP’scan access a system, read a file directory, or write to files. The benefits of an ACL are security, control, and shaping of network traffic.


An Address Resolution Protocol (ARP) links the dynamic Internet Protocol address of a host with a fixed media access control (MAC) address within a local area network via a mapping procedure. An ARP provides a translation between the 48-bit MAC address, or data link layer, and the 32-bit IP address.


Bandwidth is a connection’s data transmission capacity and indicates an internet connection or network’s speed and quality. Bandwidth measures the data transferring between two points within a specific period. In a network, bandwidth measures data flow in bits per second (bps).


Broadcasting is data transmission from one sender to all receivers within a computer network. This form of all-to-all communication can take place on Ethernet networks. Broadcasting streamlines communication within a network, optimizing efficiency within an organization. For example, a computer with the IP sends a broadcast to the entire network of (256 hosts).


Dynamic Host Configuration Protocol (DHCP) is a network management protocol. A DHCP server applies to Internet Protocol networks and automatically assigns IP addresses to connected devices via a client-server architecture. A DHCP protocol can also assign other communication parameters, such as a default gateway and subnet mask.


A Domain Name System (DNS) is a naming system that maps human domain names to networking equipment identifiers or Internet Protocol (IP) addresses. This system allows for the location and connection of devices around the globe and works similar to a phonebook. A DNS enables a browser to translate a URL to the IP address of the server storing the relevant information. For example, maps to the IP address


An extranet is a private network under the control of an organization. This type of network is accessible by users within the enterprise and by authorized outside parties, such as suppliers, clients, or independent contractors. Establishing an extranet allows for the efficient exchange of applications and data.


The internet is a worldwide connected network system that allows for global communication. Internet users can access data via public and private networks and services, such as email, instant messaging, social media, online shopping, and on-demand streaming. The internet is under the regulation of the Internet Assigned Number Authority (IANA) and other agencies.


An intranet is a private network under the ownership and control of a single organization. This network is inaccessible to outside users and allows for secure communication between an organization’s employees or other role players. Some intranet networks have social features, such as profile creation and content sharing.


A local area network (LAN) is a private network consisting of several computers that connect via WIFI or TCP/IP ethernet. LANs are generally small networks in physical locations, such as an office. A LAN connection provides several advantages, such as optimal security and high ethernet speed.


Multicasting is data transmission by one sender to multiple receivers within a computer network. A multicast differs from a broadcast in that the sender can control who receives the information. Typical uses of multicasting include the distribution of audio-visual data streams and stock market data in real-time.


Network address translation (NAT) involves mapping several local private addresses to one public address before information transfer occurs. An organization with multiple computers that only want to use one IP address will require NAT. Using NAT and consolidating multiple private IP addresses allows for IP address conservation. For example, the internet IP of (internet IP) would use a NAT address of (pubic IP) for internet access.


A packet is a data unit consisting of a header and a payload. Before data transmits over a digital network, it breaks down into packets or segments of data. When these packets reach their destination, the receiving computer reassembles them into the original data.

POE (Power over Ethernet)

Power over Ethernet means the transmission of electric power via ethernet cables, along with data. This technology allows for the deployment of devices in locations where there is no circuitry infrastructure. PoE also increases the cost-efficiency of a network installation as it reduces the need for additional electrical wiring that has to meet conduit regulations. POE is commonly used to power phones, wifi, and cameras.


A port is a virtual communication starting or endpoint within a computer network. Ports allow computers to differentiate between packets using their destination and source port numbers. As a software-based logical construct, a port is a process- or service-specific identifier. For example, web servers typically use ports 80 and 443 to host a website. DNS uses port 53, there are thousands of ports in use.


A protocol lists pre-defined guidelines or rules within a network that serve as a common language between devices. This framework of rules allows computers to identify and establish connections with each other. A protocol also defines how data transfers occur between the devices in a network. Protocol examples include TCP, UDP, IRC, SNMP, and ICMP.

Remote Authentication Dial-in User Service (RADIUS)

RADIUS is a network protocol responsible for the authentication, authorization, and accounting (AAA) of a network service. This protocol provides central authentication of a dial-in client, determines the client’s access scope, and monitors the client’s activity while connected to the network. RADIUS can be used for almost anything some common uses include, VPN access, switch, and router access.

Network Segmentation

Network segmentation, or network partitioning, is the division of a computer network into multiple smaller subnetworks, making the network more manageable. Partitioning a network prevents a single failure point from compromising the entire network, improving its security posture. Segmentation also reduces excess traffic, preventing network congestion and improving overall performance.

Common examples of network segmentation are putting computers and phones on separate networks. Printers can go on a separate network, wifi, servers, and highly critical systems. You can segment anything and it is commonly done with VLANs.

SNMP (Simple Network Management Protocol)

Simple Network Management Protocol (SNMP) is an application-layer protocol for the monitoring and management of devices within a network. An SNMP gathers and restructures data from network devices, then submits them for fault detection. Devices that communicate using this protocol include routers, firewalls, servers, switches, load balancers, and wireless devices.

Read More:
SNMP Basics

Spanning Tree

Spanning Tree is an ethernet network protocol that directs data traffic along efficient paths that don’t contain redundant loops. This protocol sits at Layer 2, which means its sole function is to direct data packets to the right destination. Spanning Tree renders all the duplicate paths for these packets inactive, ensuring a seamless flow of network communications. Spanning Tree helps prevent routing loops that can crash networks.

Split Tunnel

Split tunneling involves routing a segment of data via an encrypted virtual private network (VPN) while giving other data, such as apps, direct access to a public network, such as the internet, local area network (LAN), or wide area network (WAN). A split tunnel configuration provides users with the speed of an unencrypted link but sufficient data security where necessary.

Terminal Access Controller Access Control System (TACACS)

A terminal access controller access control system, or TACACS, is an authentication, authorization, and accounting (AAA) protocol for communicating with a remote server in a UNIX network. TACACS allows remote user network access control using allow or deny mechanisms and login details corresponding with authentication keys.


Transmission Control Protocol/Internet Protocol (TCP/IP) is the language computers use to send and receive data across the internet. This protocol suite divides network communication tasks into four layers to standardize the communications process and eliminate the need for software and hardware providers. These four layers include application, transport, internet, and network.


Throughput is the measurement of the successful data delivery over a communication channel from source to destination. In a network, throughput indicates the speed of hard drives, RAM, internet connections, and network connections. Bits per second (bps) is the unit of throughput measurement.


User datagram protocol, or UDP/IP, is a connectionless communications protocol facilitating message exchanges between computers in a network. UDP doesn’t require time to connect with the destination before data transfer, allowing for speedy communication. This protocol is ideal for time-sensitive applications, such as Domain Name System lookups. and video streams.


A unicast is data transmission from one sender to one receiver with a particular address. Unlike a broadcast or multicast, a unicast content transmission has a single destination. This network model establishes a feedback channel between the sender and receiver, and the sender has complete control over who receives the transmission.


An uplink (UL) is a connection between a local area network (LAN) and a wide area network (WAN). Users can use an uplink connection between a home network and a broadband modem so that several computers can share an internet connection. Network hubs, routers, or switches typically feature an uplink port.


A virtual extensible local area network, or VXLAN, is an encapsulation protocol for tunneling ethernet traffic over an IP network. Data centers typically use this protocol to create an overlay network over a physical network, allowing virtual network use. This protocol also allows data center network virtualization while catering to multi-tenant data center requirements and providing large-scale segmentation.


A virtual local area network, or VLAN, is a custom network consisting of one or more local area networks. VLANs play a crucial role in helping organizations overcome the physical limitations of conventional LAN networks to grow their network complexity without forgoing security measures or encountering latency issues. VLANs are used to create multiple layer 2 networks on a single physical switch.


Voice over Internet Protocol, or VoIP, is a system for placing and receiving phone calls over the internet via the transmission of data packets. Due to developments in broadband technologies, organizations are increasingly switching to VoIP telephony from the Public Switched Telephone Network. VoIP systems require an internet connection to function, and they are easily scalable.


A virtual private network (VPN) is a technology that creates a private network typically over a public network like your internet service provider (ISP). This private network is encrypted and allows a more secure connection between two endpoints. Typically organizations give employees a VPN account so they can securely connect to the corporate network securely.

VRF (Virtual Routing and Forwarding)

Virtual routing and forwarding, or VRF, is an internet protocol (IP) technology that allows for multiple routing tables on one router. This Layer 3 technology lets users deploy multiple overlapping IP addresses without conflict, enhancing network functionality.


A wide area network, or WAN, is a location-independent and extensive telecommunications network connecting devices worldwide. Unlike a local area network, WAN users don’t own the communications lines connecting them to remote systems. Instead, they subscribe to a WAN provider’s services. T


Wireless Fidelity, or Wi-Fi, is a technology involving the radio wireless networking connecting devices under IEEE 802.11 standards. When using Wi-Fi, a wireless radio emits a radio signal to a nearby device, such as a smartphone, which translates the signal into usable data. The device transmits a return radio signal to the router, which has an internet connection.


Internet Protocol Version 4, or IPv4, is the primary Internet Protocol version and the underlying technology for connecting devices to the internet. Version four IP addresses are 32-bit integers, and this scheme is running out of addresses due to the number of connected devices.

IPv4 example:, subnet


Internet Protocol Version 6, or IPv6, is the next-generation IP address standard and successor to IPv4. This scheme uses a 128-bit IP address and offers several advantages, including more efficient routing, extension flexibility, and optimal multicast routing. This protocol also offers integrated privacy and authentication support.

IPv6 example:

MAC Address

A media access control (MAC) address is a hardware identifier that pinpoints each device with a network connection. A MAC address is a hexadecimal notation consisting of 12 digits: a six-digit manufacturer identifier followed by a six-digit random device identifier. Usually, the device manufacturer assigns the MAC address, and it typically appears on the device’s network interface controller card.

MAC Address example:


Secure Socket Shell (SSH) is a network protocol giving users, such as network administrators, secure access to a remote computer to carry out network communication over an unsecured network. An SSH-based process functions on a client/server architecture, and the authorized client can enter encrypted commands for execution on the server. SSH is typically used to connect to servers, routers, and switches.

IP Address Terms

When you connect a device to a network these are the terms you should be familiar with.

IP Address

An Internet Protocol, or IP address, is a series of numbers identifying a device with an internet connection. An IP address is similar to a phone number in that it allows devices to identify and communicate with each other over a network.

Subnet Mask

A subnet mask is a number differentiating the host address and network address within an IP address. Using this number allows for the creation of subnets, or subnetworks within a network, enhancing the network’s efficiency and security. Subnetting is also helpful in optimizing the use of IPv4 addresses.

Default Gateway

A default gateway is an intermediary hardware device enabling connectivity between networks so that devices within these networks can communicate. A default gateway can be a router or a computer with adapters connecting to an outside network and the local subnetwork. The networks use this node by default, provided that an application doesn’t specify another gateway.

When connecting a device to a network you also may need to configure the DNS settings and know the DHCP server.

Network Topology


A star topology or network features a central node—for example, a hub, router, or switch. This central node acts as a server and has a physical connection to all the network components. When the central node receives data from a connecting node, it can transmit the data to other connecting nodes within the network.


In a mesh topology, an interconnection exists between all the computers within a network. Each computer in the network can transmit its own signal or relay packets from other computers. No hierarchy or interdependency exists in this scalable topology, and a single-point failure typically doesn’t affect network-wide data transmissions.


A ring network setup involves connecting devices in a circular path. Data packets in this type of topology travel from one device to the other until they reach the receiver. While this type of topology has a high data transmission capacity, the entire network is vulnerable to single points of failure.


A hybrid topology combines the connective characteristics of two or more network topologies—for example, a star-ring or star-bus topology. Implementing a hybrid topology might require the integration of several technologies, but they can provide optimal network flexibility and scalability while reducing susceptibility to system failures.


A bus topology configuration involves connecting all the devices in the network to a single line. This cable features end terminals to reduce the signal strength and prevent it from moving back and forth through the network. A bus topology is cost-effective and simplistic, but a fault on the central line can affect the entire network.

Routing Protocols


Routing information protocol, or RIP, is a vector routing protocol used to calculate optimally efficient network paths for sending data. RIP provides reachability information to all the participating routers in the form of a routing table containing a list of connected networks.


Enhanced Interior Gateway Routing Protocol, or EIGRP, is a distance-vector protocol that Cisco routers use to find the most efficient paths for data delivery. This protocol determines the optimal path to a remote network by accounting for bandwidth, line delay, load, and reliability.


Open Shortest Path First, or OSPF, is an algorithm that calculates the most optimal data transmission path to IP-based networks. If a network features multiple routers, this protocol will formulate a topography of the connections, compare the available data transmission options, and select the most efficient one, preventing unnecessary transmission delays and infinite loops.


Border Gateway Protocol is a routing protocol that the global internet uses to locate the most efficient path between large networks. This protocol communicates with other BGP systems, providing network reachability data. As a result, these systems work together to create the internet.

Network Equipment

A list of network equipment most commonly used in enterprise networks.


A switch in a computer network is a hardware device that receives incoming packets and relays them to their destination within the LAN. These TCP/IP packets contain destination information that the switch reads before selecting the suitable output port for sending the packet. A switch is more innovative than a hub and creates an electronic tunnel between the input and output ports to prevent communication collisions.

Popular enterprise switches include:


A router is network hardware connecting a local area network with a wide area network (WAN), connecting the devices in the network with the internet. These gateways manage traffic between networks by transmitting packets to their IP addresses. Multiple devices also need a router to use the same internet connection.

Access Point

A wireless access point, or WAP, is network hardware connecting a wired network to wireless-capable devices. Installing a WAP establishes a wireless network within a wired network, letting the user connect devices wirelessly, eliminating the hassle of connecting all devices using cables and wires.


A bridge is network hardware connecting multiple local area networks (LANs) with the same protocol. Consequently, the computers in these networks can communicate with each other. Bridging LANs also increases the networking capacity of each participating network.


A network hub is a piece of hardware connecting multiple ethernet devices. This node broadcasts data to every connected device and is ideal for simplistic local area networks (LANs). Unlike a switch, a hub doesn’t isolate data during a packet transfer, and communication collisions can occur.

Hubs are typically used in home networks, not enterprise networks.


Enterprise networks typically have a hardware firewall to control network traffic from internal to external networks and vis versa. Cisco, Fortigate, and Palo alto firewall are the top vendors for network firewalls. These devices can also filter users web traffic to better secure networks.

OSI Model

The OSI Model is a framework that describes how data should be transferred from one computer to another over the network.

Layer 1

Layer 1, or the physical layer, is the foundation of the Open Systems Interconnection model and features all the network hardware and data transmission technologies.

Layer 2

Layer 2, or the data link layer of the Open Systems Interconnection model, is where the encoding and decoding of data packets take place. This protocol layer allows for data transfer between devices in a network.

Layer 3

Layer 3 of the Open Systems Interconnection model is the network layer responsible for data forwarding between routers. This layer also maintains media access control and monitors layer 1 processes for errors.


Cat 5

A category 5 cable features a twisted pair design instead of a fiber-optic or coaxial cable design. This type of cable is common in ethernet connections in LANs, and they are ideal for data transmission applications such as telephony.

Cat 6

Category 6 cabling comes standard with a twisted pair design with applications that include gigabit ethernet-based networks. This type of cabling is compatible with Cat 5, 5e, and 3 standards. Cat 6 has stricter specifications and typically allows faster transfer speeds than cat 5.

Fiber Optic

Fiber optic cables are network cables containing glass fiber strands with protective and insulated casings. These cables are suitable for long-distance telecommunication and networking applications with high performance requirements.

Crossover Cable

A crossover cable has a twisted pair design and features four cable pairs. This type of cable connects two similar devices, and both ends should have the same wiring format. Crossover cable examples include loopbacks, null modem cables, and rollover cables.

Patch Cable

A patch cable typically refers to an ethernet cable (cat 5 or cat6) that is used to patch (connect) a device into the network. This can be any device such as a computer or phone that is patched into the network.

SFP Modules

Small form factor pluggable are modules typically uses to connect fiber to network equipment. Some networking equipment has an SFP port instead of an ethernet port that requires an SFP module to connect the equipment.

Fiber Connectors

Fiber cables will come with different connector types. The four below are the most common.

  • ST
  • SC
  • FC
  • LC

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