WGU C172 Network & Security Foundations Exam 2023

Star topology - ANSWER-Most common network topology today - connects all networking devices to a central switch or hub Ring topology - ANSWER-Each node connects to exactly two other nodes to deliver packets according to its designated turn or the availability of the token. Bus topology - ANSWER-Lays out all connecting nodes in a single run that acts as the common backbone connection for all connected devices Mesh topology - ANSWER-Connects a group of clients or nodes directly to each other Hub - ANSWER-Multiport repeater used to interconnect networking devices. Drawback: it broadcasts the data it receives to all devices connected to its ports. (Replaced by network switch in most modern networks) Deterministic - ANSWER-Access to the network is provided at fixed time intervals (Token Ring topology) OSI (Open systems interconnect) - ANSWER-A reference model developed by the IOS to enable different types of networks to be linked together. Contains 7 layers. Intent: to provide a framework for networking that ensures compatibility in the network hardware and software and to accelerate the development of new networking technologies. Physical layer (layer 1) - ANSWER-Signals and media: Provides the electrical and mechanical connection to the network. Examples: EIA/TIA, UTP, fiber, and network interface cards Data link layer (layer 2) - ANSWER-Provides for the flow of data: Handles error recovery, flow control (synchronization), and sequencing (which terminals are sending and which are receiving). Considered the "media access control layer" and is where Media Access Control (MAC) addressing is defined. Ethernet 802.3 standard is defined in this area. (MAC address sometimes called the Ethernet address) Network layer (layer 3) - ANSWER-Provides routing decisions: Accepts outgoing messages and combines messages or segments into packets, adding a heading that includes routing information. It acts as the network controller. Examples: IP and IPX (Internetwork packet exchange) Transport layer (layer 4) - ANSWER-Ensures error-free packets: Concerned with message integrity between source and destination. Segments/reassembles (the packets) and handles flow control. Examples: TCP, User Datagram Protocol (UDP) Session layer (layer 5) - ANSWER-Establishes, maintains, and terminates sessions: Provides the control functions necessary to establish, manage, and terminate the connections as required to satisfy the user request. Examples: Network File System (NFS), SQL Presentation layer (layer 6) - ANSWER-Protocol conversion, data translation: Accepts and structures the messages for the application. It translates the message from one code to another if necessary. Responsible for data compression and encryption. Examples: ASCII, JPEG Application layer (layer 7) - ANSWER-Support for applications: Interacts with application programs that incorporate a communication component such as your Internet browser and email. This layer is responsible for logging the message in, interpreting the request, and determining what info is needed to support the request. Examples: HTTP, FTP, SMTP Layer 1 (issue) - ANSWER-Issue: The connection to the machine is down - a cabling problem Layer 3 (issue) - ANSWER-Issue: The network is down, or a router problem Layer 7 (issue) - ANSWER-Issue: A service on a specific machine is down - a network is having problems accessing an email server that uses SMTP Layer 3 test - ANSWER-Ping the IP address to check quickly that there is a network connection reply from - ANSWER-response for a ping that indicates the connection to the server is up request timed out - ANSWER-response for a ping that indicates the network connection is down (could be a problem with: cabling, a switch, a router, email server down) Layer 2 (issue) - ANSWER-Issue: problem with a switch Physical Data Network Transport Session Presentation Application - ANSWER-Please do not throw sausage pizza away (mnemonic device to remember OSI from 1 to 7) Application Presentation Session Transport Network Data Physical - ANSWER-All people seem to need data processing (mnemonic device to remember OSI from 7 to 1) MAC (Media accessing control) - ANSWER-Layer 2 - ipconfig /all in command line. 6 bytes (48 bits) displayed in 12 hex digits. Also called the Ethernet, physical, hardware or adapter address. IP address - ANSWER-Layer 3 - IPv4 or IPv6 - ipconfig /all - subnet mask, default gateway, dns assignment TCP/IP protocol suite - ANSWER-Transport layer & network layer protocol combination - **reliable UDP (User datagram protocol) - ANSWER-sending network data with as little overhead as possible - **unreliable Data encapsulation - ANSWER-Information added as data moves down the model (IP in level 3, MAC in level 2) Data de-encapsulation - ANSWER-Information removed as data moves up the model Bits - ANSWER-Data in layer 1 (physical) Frames - ANSWER-Data in layer 2 (data link) Packets - ANSWER-Data in layer 3 (network) Segments - ANSWER-Data in layer 4 (transport) (Data) Segments Packets Frames Bits - ANSWER-Some people fear birthdays (mnemonic device to remember names for data from level 4 to 1) - "Data" is top 3 layers TCP/IP model - ANSWER-Application, Transport, Internet, Network Interface - Predates OSI -- Not granular enough HTTP FTP SMTP - ANSWER-Function at layer 7 (application) ASCII JPEG - ANSWER-Function at layer 6 (presentation) NFS SQL - ANSWER-Function at layer 5 (session) TCP UDP - ANSWER-Function at layer 4 (transport) IP IPX - ANSWER-Function at layer 3 (network) MAC (media access control) addresses - ANSWER-Function at layer 2 (data link) NICs (network inferface cards) cable fiber - ANSWER-Function at layer 1 (physical) CSMA/CD (Carrier sense multiple access with collision detection) - ANSWER-The Ethernet LAN media-access method: it first "listens" to see whether there is any data traffic (carrier sense), and any of the computers on the LAN can access the network (multiple access) -- if 2 or more computers attempt to broadcast a message at the same time, the system must have the capability to detect data collisions (collision detection) Ethernet - ANSWER-The networking protocol used in most modern computer networks Ethernet packet frame - ANSWER-Preamble, start frame delimiter, destination MAC address, Source MAC address, length type, data, pad, frame check sequence. Minimum size: 64 bytes. OUI (organizationally unique identifier) - ANSWER-The first 6 digits of the MAC address used to indicate the vendor of the network interface IANA (Internet Assigned Numbers Authority) - ANSWER-IP network numbers are assigned by the ____ IPv4 - ANSWER-A 32-bit address that identifies on which network the computer is located and differentiates the computer from all other devices on the same network. Format: A.B.C.D Class A - ANSWER-IP address class for governments, very large networks 0.0.0.0 to 126.255.255.255 Private address range: 10.0.0.0 - 10.255.255.255 PRIVATE, non-routable Class B - ANSWER-IP address class for midsize companies, universities, and so on 128.0.0.0 to 191.255.255.255 Private address range: 172.16.0.0 - 172.31.255.255 Class C - ANSWER-IP address for small networks 192.0.0.0 to 223.255.255.255 Private address range: 192.168.0.0 - 192.168.255.255 Class D - ANSWER-IP address reserved for multicast groups (224.0.0.0 to 239.255.255.255) Private addresses - ANSWER-IP addresses set aside for use in private intranets IP internetwork - ANSWER-A network that uses IP addressing for identifying devices connected to the internet 802.11a (Wireless-A) - ANSWER-This wireless standard can provide data transfer rates up to 54Mbps and an operating range up to 75 feet. Uses OFDM (Orthogonal frequency-division multiplexing) modulation technique operating at a frequency of 5GHz - supports 8 overlapping channels 802.11b (Wireless-B) - ANSWER-This wireless standard can provide data transfer rates up to 11Mbps with ranges of 100-150 feet. Uses DSSS (Direct Sequence Spread Spectrum) operating at a frequency of 2.4GHz - supports 3 non-overlapping channels 802.11g (Wireless-G) - ANSWER-This wireless standard can provide data transfer rates up to 54Mbps up to 150 feet. Can use either DSSS of OFDM, operates at 2.4GHz 802.11n (Wireless-N) - ANSWER-This wireless standard provides data transfer rates up to 4 x 802.11g speeds (200+Mbps). It operates at either 2.4GHz or 5GHz -- SPEED increases *MIMO (Multiple input multiple output) 802.11ac (Wireless-AC) - ANSWER-This is the latest wireless standard. It provides single-station data transfer rates of 500Mbps and operates in the 5GHz frequency band Switch - ANSWER-Best choice for interconnecting networking devices - can establish a direct connection from sender to destination without passing data traffic to other networking devices Network adapter - ANSWER-Available wired and wireless - A NIC is the desktop version, and is inserted into an expasion slot on the computer's motherboard (wired-only) Router - ANSWER-Networking device used to connect two or more networks (ex: your LAN and the Internet) Access point - ANSWER-Used to interconnect wireless devices and provide a connection to the wired LAN Broadband modem (gateway) - ANSWER-Device used to provide highspeed data access via your cable connection or via a telephone company's DSL connection (combines a modem and a router into one box) Cable modem - ANSWER-Device used to make a broadband network connection from your home network to the ISP using your cable connection. Requires a splitter to separate the cable TV from the home network. DSL modem - ANSWER-Device used to make a broadband network connection from your home network to the ISP using the phone line Wireless-N - ANSWER-Best data transfer rates for a wireless home network, cost to switch is minimal, and is a suitable alternative to a wired network