FINALS

• Star Topology


  • Computers are connected to a single hub through a cable
  • The hub is the central node
• Bus Topology


  • Every computer and network device is connected to a single cable
  • When it has exactly two endpoints, then it is called a linear Bus Topology
  • All nodes are connected through a bus (ex. Coaxial cable)
• Ring Topology


  • Form a ring as each computer is connected to other computer
  • With the last one connected to the first
  • Exactly two neighbors for each device
• Tree Topology


  • Also called hierarchical topology
  • Has a root node and all other nodes are connected to it forming a hierarchy
• Mesh Topology


  • A point-to-point connection to other nodes or devices
• Partial Mesh Topology


  • Some systems are connected in the same fashion as mesh topology
• Full Mesh Topology


  • Each node or device is connected
• Hybrid topology


  • Consists of a mix of two different types of topologies
• Line of Sight Propagation Method

  • Radio waves travels from the transmitting antenna to the receiving antenna
  • The two antennas must see each other
• Radio Frequency Bands


  • Very High Frequency (VHF) - 30MHz - 300MHz - AM aircraft communication, Aircraft navigational aids
  • Ultra-High Frequency (UHF) - 300 MHz - 3Ghz - UHF television, Cellular telephone, radar, microwave links, personal communication systems
  • Super High Frequency (SHF) - 3GHz - 30GHz - Satellite communication, radar, terrestrial microwave links, wireless local loops
  • Extremely High Frequency (EHF) - 30GHz - 300THz - Experimental, wireless local loop
  • Infrared (IR) - 0.3THz - 300THz - Heating and drying, night vision cameras, TV and garage door remotes, satellite, remote sensing
  • Visible light - 0.3 PHz - 3 PHz - Optical Communication
• Ground Wave (Surface) Propagation Method

  Radio waves are radiated directly towards the earth's surface
• Ground Wave Propagation Frequency Bands

  • Extremely Low Frequency (ELF) - 30Hz - 300Hz - AC power line frequencies and low-frequency telemetry signals
  • Voice Frequency (VF) - 300Hz - 3kHz - Telephone system for analog subscriber lines
  • Very Low Frequency (VLF) - 3KHz - 30KHz - Military systems and submarine communication
  • Low Frequency (LF) - 30KHz - 300rKHz - Long-range navigation and marine communication
• SkyWave (Ionospheric) Propagation Method

  Radio waves radiate upwards from the transmitting antenna of the earth into a direction towards the ionosphere
• SkyWave Propagation Frequency Bands

  • Medium Frequency (MF) - 300KHz - 3MHz - Commercial AM radio broadcasting
  • High Frequency (HF) - 3MHz - 30 MHz - Internation broadcasting, military communication, long-distance aircraft, ship communication
  • Very High Frequency (VHF) - 30MHz - 300MHz - VHF Television, commercial FM Broadcast
• Space Wave (Tropospheric) Propagation Method

  • Radio waves radiation exceeds 30MHz to 300GHz
  • Used for sound/television broadcasting for radio-relay system
• Network ID/Field


  Identifies the host that is located on the same physical network
• IP Address Classes


  • Class A address - Uses only the first octet of the 32 bits, 24 bits, Network.Host.Host.Host
  • Class B address - Uses two of the four octets of the 16 bits, 16 bits, Network.Network.Host.Host
  • Class C address - Uses the three octets of the 24 bits, 8 bits, Network.Network.Network.Host
  • Class D address - Created to enable multicasting using an IP address, Host.Host.Host.Host
  • Class E address - Reserved by the Internet Engineering Task Force (IETF) for its own research
• Multicast address


  A unique address that directs packets with the destination address to predefined groups of hosts
• Simple Network Management Protocol (SNMP)


  • Monitors and controls the exchange of management information
  • Managed Devices, Agent, NMS
• ANDing IP Address


  To tell where to break the IP address apart to get the parts, the IP address must be "ANDed" with its default mask in binary
• Three-way handshake


  1. Inform their respective OS that a connection will be initiated before the actual data communication begins

  2. SYN - Synchronize

  3. ACK - Acknowledge

  4. FIN - Finish
• Sequence Number and Acknowledgement Number

  Fields to implement reliable and ordered data transmission
• Windows Sliding Mechanism


  Requires the sender to receive an acknowledgement from the receiver after transmitting a certain amount of data
• TCP Shutdown (Four-Way Handshake)


  When the data transmission is complete in order to disconnect the TCP connection and release system resource
• HTTP Port 80


  Hypertext Transfer Protocol
• OSI Layers


  • Physical layer - raw bits (1s or Os) transmitted physically via the hardware
  • Data Link layer - a frame (or series of bits)
  • Network layer - a packet that contains the source and destination address
  • Transport layer - a segment that includes a TCP header and data
  • Session layer - the data passed to the network connection
  • Presentation layer - the data formatted for presentation
  • Application layer - the data received or transmitted by a software application