Ch.14 - Networking Technology Basics Flashcards
3 Basic components in every computer
- Central Processing Unit: Math calculations with assistance of ALU and RAM
- Input/Output: Used to transmit data from CPU for processing (peripheral devices used)
- Data Storage: May be fixed in semi-permanent location or removable (ex: hard disk)
- Multiprocessor computers and computers based on multicore CPUs are designed to deal with
the demands of process-intensive applications
o Multiprocessor systems can perform high-security processing with a separation of duties
Shell
UI – command-line or graphical interface
Determining best computer class
Variety of size/prices/processing power/throughput/data storage
Supercomputers
Designed for intense scientific calculations - Nuclear
Mainframe computers
Large/scalable, general-purpose systems to supp big volumes of data
o Multithreading: Execute in parallel to minimize idle time in processor
Midrange computers
To be operated by individual deps or smaller orgs
Microcomputers
PC, notebook, PDA, designed for individual users
RAID
Redundant Array of Inexpensive Disks or Redundant Array of Independent Disks (view RAID table for different levels)
Protocol
Standard procedures/rules to organize comm process (AKA computer port)
Open Systems Interconnect (OSI) Model
▪ Application Layer: Interacts with end users through programs interacting within a network
▪ Presentation Layer: Coding of data (file formats and character representations – encryptions)
▪ Session Layer: Maintains comm sessions between computers ((dis)connect)
▪ Transport Layer: Breaks data into packets and properly transmit it over the network
▪ Network Layer: Logical implementation of network (logical addressing takes form of IP address)
▪ Data Link Layer: Transmit/receive info on computers connected to LAN (uses MAC addresses)
▪ Physical Layer: Physical operation of network - Translates binary 1/0 of computer language for T
View OSI Figures
Network routing
Process of directing traffic
to the intended destination.
Data will travel on the network on predetermined routes to reach their destinations. Same as driving on the highway. Can only change it manually by network admins.
OSI communication between systems
Users make a request in their app software on layer 7. It passes through each layer and transform the request into a series of electrical signals.
The packet is routed to its intended destination computer.
Layer 1 of the other computer receives the signal and passes through each of the layers again.
Routers
Forward data traffic when necessary and insulate users on other subnets
- Router ignores traffic on same subnet (LAN1 to LAN 1)
Border routers
Subject to direct attack from an outside source.
- When you configure router, determine whether it’s lone point of defense or part of a multilayered defense (multi is better as lone is subject to attack itself)
Internal routers
Provide enhanced features to your internal networks
- Can keep traffic out of a subnet and keep traffic in a subnet (more confidential/ no crossover)
Ethernet Networks
Defines the way that computers communicate on the network
- Governs both the Physical (Layer 1) and Data Link layers (Layer 2)
- Defines how computers use MAC addresses to communicate on network
o Ethernet has become the most common LAN technology in use
Bus Topology
Daisy-chained connection, meaning single coaxial cable passing through connector on back of each computer on network (ties all systems together - if it breaks, everything breaks).
Star Topology
Each computer has a dedicated cable connection running to network hub/switch. Offers cable redundancy ensuring computers’ network are not interconnected.
Ring Topology
Each LAN computer is connected to a media access unit (MAU). Each MAU is connected to an upstream MAU and downstream MAU to form a backbone loop. Network traffic is bidirectional.
Meshed Network
Series of point-to-point connections between critical backbone connections. Routers determine which link to use based on predefined routing criteria (admin does this).
- Full Mesh: Has alternate connections for every major backbone point on network
- Partial Mesh: Only has for most critical links
Coaxial Cable
Have mesh shielding to prevent electrical interference (old)
Unshielded Twisted-Pair (UTP) Cable*
Wire doesn’t have protection from electrical interference. Pairs are twisted to reduce electromagnetic interference (EMI)
Fiber Optic Cable
LED used to flash signals through glass strands. Commonly used for backbone connections and long-haul installations (dense wave multiplexing)
Hubs
Electrical connection box amplifying and retiming electrical signals for transmission
• Contain number of plugs (or ports) to connect Ethernet cables for different network systems
• Receive packets and automatically retransmit those packets to all the other ports (shared)
Switches
Separate traffic between ports to create appearance of private comms line
• Perform intelligent filtering – capable of running logic programs
• “Know” the MAC address of the system connected to each port
• When they receive a packet on the network, they look at the destination MAC address and send the packet only to the port where the destination system resides
Virtual LANs (VLANS)
To divide users by simulating one subnet for all target computers
- Any broadcast domain that is isolated from other domains
- Collection of logically related network devices that are viewed as a partitioned network segment
- Used to isolate logical groups of devices to reduce network traffic and increase security
Domain Name System (DNS)
The how you end up reaching a website without knowing its IP address
- DNS servers are layer of 7 software app containing list of alias names and their IP addresses
Lack of security
Network productivity shut down if DNS server is lost/attacked
Risk of fake DNS updates
Dynamic Host Configuration Protocol (DHCP)
Automatically configure IP address, subnet mask and DNS settings on computer
- Used within network to simplify configuration of each user’s computer
- DHCP server needs to be located on same subnet to hear computer making DHCP requests
LAN (Local Area Network)
▪ Systems on the same LAN do not protect themselves from each other
▪ Good security is important