networking

• IP


  Internet Protocol
• IPv4


  Version Four of the Internet Protocol
• IPv4 was the primary version brought into action for production within the ARPANET in 1983
• IPv4 address


  32-bit integer expressed in decimal notation
• IPv4 address

  • 192.0.2.126
• Network part of IPv4 address


  • Indicates the network the address belongs to
  • Identifies the network class

  
• Host part of IPv4 address


  • Uniquely identifies the machine on the network
  • Varies for each host on the same network

  
• Subnet number


  • Optional part of IPv4 address
  • Used to divide large networks into smaller subnets
• Characteristics of IPv4


  • 32-bit address
  • Numeric address with bits separated by dots
  • 12 header fields with 20 byte length
  • Supports unicast, broadcast, and multicast
  • Supports VLSM
  • Uses ARP to map to MAC address
  • Supports RIP routing protocol
  • Requires manual or DHCP network design
  • Allows packet fragmentation

  
• IPv4 security


  • Permits encryption to maintain privacy and security
• IPv4 network allocation

  • Significant with over 85,000 practical routers
• IPv4 communication

  • Provides quality of service and efficient data transfer
• IPv4 addressing

  • Allows flawless encoding and scalable, efficient routing
• IPv4 multicast


  • Enables more specific data communication across networks
• Subnet mask


  • 32-bit number used to identify the subnet of an IP address
  • 1s represent network and subnet ID, 0s represent host ID

  
• Identifying subnet of destination IP address

  1. Bitwise AND destination IP with subnet mask

  2. Result is the network ID the address belongs to

  
• Classful IP addressing


  • 32-bit IP address divided into 5 classes (A, B, C, D, E)
  • Classes determine network ID and host ID bits

  
• Classful IP address classes

  • Class A
  • Class B
  • Class C
  • Class D
  • Class E
• Class A IP addresses

  • 8-bit network ID, 24-bit host ID
  • 126 possible networks, 16.7 million hosts per network

  
• Class B IP addresses

  • 16-bit network ID, 16-bit host ID
  • 16,384 possible networks, 65,534 hosts per network

  
• Class C IP addresses

  • 24-bit network ID, 8-bit host ID
  • 2 million possible networks, 254 hosts per network

  
• Class D IP addresses

  • Reserved for multicasting
• Class E IP addresses

  • Reserved for experimental and research purposes
• Special IP address ranges

  • Link-local addresses: 169.254.0.0 - 169.254.0.16
  • Loopback addresses: 127.0.0.0 - 127.0.0.8
  • Used for local network communication: 0.0.0.0 - 0.0.0.8

  
• Host IDs cannot be all 0s (network ID) or all 1s (broadcast address)

  
• Network IDs cannot start with 127 (reserved for loopback) or have all bits set to 1 (broadcast address)

  
• Network IDs cannot have all bits set to 0 (used to denote a specific local host)