IS 450 Exam 1
Type
A 2-byte field in the Ethernet Frame that identifies the type of protocol that is encapsulated within the data.
FCS
A 4-byte field in the Ethernet Frame that contains the Frame Check Sequence and detects errors.
RJ-48 Connector
A cable that looks like the RJ-45 connector but uses shielded twisted pair cables, primarily used with T1 lines.
USB Connector
A common connector on desktops and laptops that can be used for many different purposes such as Wi-Fi and wired network adapters.
Flat Network
A common design in simpler deployments that does not require scalability. In this design, all devices can connect to other devices on the network without layer 3 segmentation. The flat network does not have an internal security mechanism.
ISP (Internet Service Provider)
A company that provides internet access to end-users.
Ethernet Frame
A data packet used in the data link layer of computer networking that contains a source and destination address, type, data, and frame check sequence.
Router
A device that facilitates communication between networks and provides a traffic control point such as security, filtering, or redirecting. Routers learn which networks they're attached to by IP addresses for each network.
Switch
A device that facilitates communication within a network. Switches are a combination of hubs, which many devices can connect to, and bridges, which learn which hosts are connected to each port. The switch knows to send data between hosts on a per-port basis.
Repeater
A device that strengthens the signal of data crossing a wire. This allows communication across greater distances.
UTP Coupler
A device used to connect two RJ-45 network cables together to extend the length of cables.
Fiber Coupler
A device used to join two fiber-optic cables.
Bridge
A dual-port device that sits between Hub-connected hosts. The bridge will learn which host are on each side, allowing communication to the necessary side.
RJ-11 Connector
A four-wire connector mainly used to connect telephones, but can also connect computers to a network through the computer's modem.
Internet
A global network of computer systems that enables the exchange of information, communication, and collaboration across geographical boundaries.
3-Tier Network
A hierarchical design that consists of a core layer, distribution (aggregation) layer, and an access layer. This design is mostly found on campus LAN network design and is good at enabling north-south traffic. The core layer is at the top of the 3-tier network.
Networks
A logical group of hosts which require similar connectivity. A network can contain other networks called sub-networks. All networks are connected to a main network source called the internet.
Hub
A multi-port repeater that connects multiple hosts, facilitating scaling communication between additional hosts. The main issue is that everyone receives each other's data.
Collapsed Core
A network architecture that combines the core and distribution layers of the 3-tier network architecture. This architecture is suitable for smaller networks with fewer devices.
Spine-Leaf Network
A network architecture that consists of a spine layer and a leaf layer. The spine layer provides connectivity between the leaf layer, which is designed for user device connectivity such as workstations and printers. This architecture is suitable for large data centers or cloud computing environments.
Content Provider Network (CPN)
A network infrastructure that provides content distribution services to end-users. Examples: Akamai, Cloudflare, Amazon CloudFront
Botnet/DDoS attacks
A network of compromised computers controlled by a single attacker, often used to launch Distributed Denial of Service (DDoS) attacks, flooding a target system with traffic, causing it to become unavailable to users.
IXP (Internet Exchange Point)
A physical location where multiple ISPs connect to exchange internet traffic.
Intranet
A private network within an organization used to share information, resources, and applications, only accessible by authorized users within the organization.
How a Router Works
A router is a networking device that connects multiple networks together and forwards data packets between them. A router works by examining the destination address of each packet it receives and determining the best path to forward the packet.
Protocol
A set of rules and standards that govern communication between devices on a network, defining how data is transmitted, received, and interpreted.
SC Connector
A single squared connector commonly used between floors in a building, one of the first fiber-optic connectors used in the marketplace.
F-Type Connector
A threaded connector typically used on coaxial cable, used to attach to cable modems and satellite internet.
Spyware
A type of malware designed to gather information from a user's computer without their knowledge or consent, collecting personal data such as login credentials, browsing history, and credit card details.
Virus
A type of malware that can replicate itself and infect other files and systems, often spread through email attachments, infected websites, and removable storage devices.
Worm
A type of malware that can replicate itself and spread through networks without user interaction, unlike viruses.
Cable Modem
A type of network line service that provides high-speed Internet access over a cable TV network, offering speeds up to 1 Gbps and distances up to 1000 feet.
Dial-up Internet
A type of network line service that uses a telephone line to connect to the Internet, offering low speeds and limited distance.
Malware
A type of software designed to harm computer systems and networks, including viruses, worms, spyware, and other malicious programs.
Cellular Network Internet
A type of wireless internet connection that uses cellular networks to connect to the Internet, requiring a cellular data plan.
Internet Packet
A unit of data that is transmitted over the internet, consisting of a header and a payload.
Addressing
Addressing is the process of assigning unique identifiers to network devices so that they can be located and communicated with over a network. IP addressing is used in the network layer to identify devices on a network.
LC Connector
Also called the Local Connector, used between floors in a building and competes with the SC Connector. Half the size of the SC connector and is best used on racks and panels.
MTRJ Connector
Also called the Mechanical Transfer Register Jack, a connector designed to connect the SC connector, uses two fiber cables in a single design and resembles the RJ45.
ST Connector
Also called the Straight-Tip Connector, commonly used with single mode fiber-optic cables. Developed by AT&T, its usage is declining due to the demand for smaller connectors.
RJ-45 Connector
An 8-pin connector used to connect computers and other network devices on LAN that uses unshielded twisted pair (UTP) cable.
BNC Connector
An RF connector that uses coaxial cable, used with both analog and digital video transmission and audio.
Satellite
An internet connection that uses satellite communication to transmit data, ideal for remote or rural areas where other types of internet connections are not available.
Host
Any device which sends or receives traffic, such as computers, laptops, phones, printers, servers, cloud servers, and IoT. Hosts are categorized as Clients, which initiate requests, and Servers, which respond to requests.
BPL
Broadband over Powerlines, an internet connection that uses electrical power lines to transmit data, providing high-speed internet access over the existing electrical infrastructure in a building or neighborhood.
Network Line Services
Communication services that provide access to the Internet and other networks, differing in terms of speed, distance, and technology used.
DSL
Digital Subscriber Line, a type of network line service that provides high-speed Internet access over traditional copper telephone lines.
DNS
Domain Name System, a protocol for translating domain names to IP addresses.
DHCP
Dynamic Host Configuration Protocol, a protocol for assigning IP addresses to devices on a network.
Fiber
Fiber-optic cables used to transmit data over long distances, offering faster data transfer rates than traditional copper cables.
FTP
File Transfer Protocol, a protocol for transferring files over the Internet.
Forwarding versus Routing
Forwarding is the process of transferring a packet from one interface of a router to another interface of the same router. Routing is the process of determining the best path for a packet to reach its destination.
FDM
Frequency Division Multiplexing, a method of transmitting multiple signals over a single communication channel by dividing the bandwidth into multiple frequency bands.
Generalized Forwarding
Generalized forwarding refers to the process of forwarding packets based on any packet field, not just the destination IP address. This allows for more flexible routing and network virtualization.
HTTP
Hypertext Transfer Protocol, a protocol for transmitting web pages over the Internet.
IOIT
Information and Operations Technology, which refers to the integration of IT and OT to streamline business operations and improve efficiency.
ICMP
Internet Control Message Protocol, a protocol for error reporting and diagnostics.
IMAP
Internet Message Access Protocol, a protocol for accessing email messages on a mail server.
NAT, Middleboxes
Network Address Translation (NAT) is a technique used to allow multiple devices on a local network to share a single public IP address. Middleboxes are networking devices that perform various network functions, such as firewalls, proxies, and load balancers.
ICMP (Internet Control Message Protocol)
No specific #
Packet Loss
Occurs when one or more packets fail to reach their destination, caused by network congestion, faulty equipment, or transmission errors.
Access Points, Firewalls, Load Balancers, Layer 3 Switches, IDS/IPS Proxies, Cloud Switches, Virtual Switches, Virtual Routers
Other network devices that use routing, switching, or both.
POP3 (Post Office Protocol version 3)
Port 110
IMAP (Internet Message Access Protocol)
Port 143
FTP (File Transfer Protocol)
Port 21
SSH (Secure Shell)
Port 22
SMTP (Simple Mail Transfer Protocol)
Port 25
DNS (Domain Name System)
Port 52
HTTP (Hypertext Transfer Protocol)
Port 80
DHCP (Dynamic Host Configuration Protocol)
Ports 67 and 68
POP3
Post Office Protocol version 3, a protocol for receiving email messages.
Commercial ISPs
Private companies that provide internet access to individuals, organizations, and other entities for a fee. Examples: Comcast, AT&T, Verizon
Wireless
Radio waves used to transmit data between devices, including technologies like Wi-Fi, Bluetooth, and cellular networks.
SSH
Secure Shell, a protocol for secure remote login and other secure network services.
SSL/TLS
Secure Sockets Layer/Transport Layer Security, a protocol for secure communication over the Internet.
SMTP
Simple Mail Transfer Protocol, a protocol for transmitting email messages over the Internet.
IP Protocol
The IP (Internet Protocol) is a network-layer protocol used for communication between devices on a network. It is responsible for addressing, routing, and forwarding data packets between devices.
Internet Architecture
The Internet architecture refers to the overall design and structure of the Internet. It is based on a hierarchical system of interconnected networks, with the core backbone networks providing high-speed connectivity between regions.
IoT
The Internet of Things, physical objects with sensors and processing ability that connect and exchange data with other devices and systems over the Internet or other communications networks.
Source Address
The MAC address of the destination device.
Packet Throughput
The amount of data that can be transmitted over a network in a given time period, influenced by various factors such as network bandwidth, packet size, and congestion.
Packet Delay
The amount of time it takes for a packet to travel from its source to its destination, influenced by various factors such as network congestion, routing protocols, and distance.
Control Plane
The control plane is the part of a networking device that is responsible for making routing decisions. It communicates with other routers in the network to determine the best path for a packet to reach its destination.
Data Plane
The data plane is the part of a networking device that is responsible for forwarding data packets. It performs the actual forwarding of packets based on the routing decisions made by the control plane.
IP Addresses
The identity of each host needed to communicate over the internet. IP addresses are stamped on everything each host sends. When a client sends a web request to the server, the packet being sent will have both source and destination IP addresses stamped to it.
Preamble
The initial 8 bytes of an Ethernet Frame that is used for synchronization and clock synchronization.
Internet Security
The measures taken to protect computer systems and networks from unauthorized access, theft, and damage.
Network Layers
The network layer is the third layer of the OSI model that provides communication between devices in different networks. It is responsible for the routing of data packets from the source to the destination.
Network Layer Service Models
The network layer service models define the services that the network layer offers to the upper layer protocols. The two main network layer service models are connection-oriented and connectionless service.
Network edge
The part of the network closest to end-users or devices, including equipment like computers, routers, switches, and modems.
Data
The payload of the Ethernet Frame that contains the request in an IPv4 header and other stacked headers.
Destination Address
The physical address of the device on the network interface card, also known as the MAC address.
Multiplexing
The process of combining multiple data streams into a single data stream by adding a transport header occurs on transport layer.
Routing
The process of moving data between networks.
Switching
The process of moving data within networks.
De-multiplexing
The process of separating a single data stream into multiple data streams by using header information to deliver received segments to the correct socket occurs on transport layer.
Two Key Network-Layer Functions
The two key network-layer functions are routing and forwarding. Routing is the process of determining the best path for a packet to reach its destination, while forwarding is the process of transferring a packet from one interface of a router to another interface of the same router.
TDM
Time Division Multiplexing, a method of transmitting multiple signals over a single communication channel by dividing the time into multiple time slots.
TCP/IP
Transmission Control Protocol/Internet Protocol, the set of communication protocols used for the Internet and other networks.
UPC vs. APC End Faces
UPC connectors have imperfect connections due to small imperfections in the glass, causing signal loss. APC connectors solve this by angling the tips, allowing the reflected light to bounce up at an angle and not cause signal loss.
UDP
User Datagram Protocol, a connectionless protocol for transmitting data packets over the Internet and other networks.
Peer-to-Peer Content Delivery Network
a CDN technology that leverages the Peer-to-Peer (P2P) protocol for web content distribution.
OSI Model
a conceptual framework that describes how data communication occurs between different systems in a network. The model is divided into seven layers, each with a specific role in the communication process. These layers include the physical layer, data link layer, network layer, transport layer, session layer, presentation layer, and application layer.
TCP (Transmission Control Protocol)
a connection-oriented protocol used for reliable transmission of data over the internet.
Pull CDN
a content delivery network type where content delivery networks are responsible for "pulling" web content that is served to end-users once a request is received.
Push CDN
a content delivery network type where origin servers send web content to CDN servers directly.
SSL (Secure Sockets Layer)
a cryptographic protocol that provides secure communication over a network. It is the predecessor of TLS and is no longer considered secure.
HTTPS (Hypertext Transfer Protocol Secure)
a more secure version of HTTP that uses encryption to protect data being transmitted between a server and a client.
DHCP (Dynamic Host Configuration Protocol)
a network management protocol used to automatically assign IP addresses and other network configuration parameters to devices on a network.
VPN (Virtual Private Network)
a network technology that allows users to securely connect to a private network over the internet. VPNs are often used by businesses to allow remote workers to access company resources securely.
HTTP (Hypertext Transfer Protocol)
a protocol used for transferring data over the internet, typically for web page requests and responses.
RSA
a public-key cryptosystem used in encryption and digital signatures. It is named after its inventors: Ron Rivest, Adi Shamir, and Leonard Adleman. RSA is widely used in securing internet communication, such as SSL/TLS and VPNs.
DNS (Domain Name System)
a system for translating human-readable domain names into IP addresses.
CDN (Content Delivery Network)
a system of distributed servers that deliver web content, such as images, videos, and other static or dynamic content, to a user based on their geographic location, the origin of the webpage, and the server capacity.
SDN (Software-Defined Networking)
an approach to networking that allows network administrators to manage network services through abstraction of lower-level functionality.
Session Layer
establishes, manages, and terminates communication sessions between applications.
Infrastructure Layer
includes the network devices, such as switches and routers, and the physical network infrastructure.
SSL/TLS (Secure Sockets Layer/Transport Layer Security)
port 443
Application Layer
provides access to network services for applications. It is the layer where user interactions occur.
Transport Layer
provides end-to-end communication between applications on different devices. It ensures that data is transmitted reliably and efficiently.
Data Link Layer
provides reliable transmission of data over a physical link. It breaks up data into frames and ensures that they are transmitted error-free.
Presentation Layer
responsible for data representation and encoding. It ensures that data is presented in a format that can be understood by the application layer.
Control Layer
responsible for managing the network traffic and policies. It includes the SDN controller and network operating system, which interacts with the infrastructure layer.
Physical Layer
responsible for the physical transmission of data over a communication channel. This includes the hardware, cabling, and signaling.
Network Layer
responsible for the routing and forwarding of data between different networks. It also handles addressing and fragmentation of data.
TLS (Transport Layer Security)
the current standard for secure communication and is used in applications such as web browsing, email, and instant messaging.
Application Layer
where the SDN applications reside. It includes the user interfaces, network services, and other applications that interact with the SDN controller.