Module 4

• Requirements for Internet Connection

  • Physical Connection: Establishing connectivity via modem, router, or LAN card
  • Modem: Converts digital signals to analog for telephone line connectivity
  • Router: Directs data packets between networks
  • LAN Card: Provides network communication capabilities to PCs
  • Logical Connection: Utilizing standards or protocols such as TCP/IP
  • Applications: Interpreting data and displaying information through web browsers, FTP, etc.
• Network Interface Card (NIC)

  Provides network communication capabilities, often integrated into motherboard slots
• NIC

  • External NICs are also available for expansion
• Modem


  Converts digital signals to analog for connectivity via telephone lines
• Types of Modems

  • PC Card Modem: Portable modem for laptops
  • Internal Modem: Installed within the computer
  • External Modem: Connected externally to the computer
• Evolution of Modem Speed

  1. Modem speeds evolved from 300 bps in the 1960s to Mbps in the 2000s due to technological advancements and user demands

  2. Historical context: Evolution of modem speeds from 300 bps to 56 kbps and beyond
• TCP/IP

  Protocols enable resource sharing across networks
• TCP (Transmission Control Protocol)

  Ensures reliable data delivery
• IP (Internet Protocol)

  Handles packet routing
• Testing Connectivity with PING

  1. Ping verifies IP address existence and responsiveness using ICMP Echo Request datagrams

  2. Internal Loopback Test: ping 127.0.0.1

  3. Host PC Ping: ping <IP address of host computer>

  4. Default Gateway Ping: ping <default-gateway IP address>

  5. Remote Destination Ping: ping <remote destination IP address>

  6. Output Interpretation: Success ratio and round-trip time
• IP Address

  A 32-bit address used to uniquely identify a computer on a network. It consists of network and host IDs.
• Network ID

  Identifies the network where the computer sits
• Host ID

  Uniquely identifies the computer on its network
• Network Mask

  Assigned to computers, where some bits represent a network, and others identify a particular computer
• Rules for IP Addressing

  • Restrictions on the first octet, host ID values, and definitions of network and broadcast IDs
  • 127 range reserved for diagnostics (loopback address)
  • Host ID cannot be all 0's or all 255's
• Network ID

  A numeric/symbolic address that uniquely distinguishes a network node or device over a computer or telecommunications network
• Broadcast ID


  A special IP address used to transmit messages and data packets to network systems
• Purposes of Subnetting

  • Control network traffic
  • Segregate flow of network traffic between hosts
  • Regulate IP traffic
  • Improve network security and performance
• Why Subnetting?

  • Addresses scalability and routing table efficiency
  • Reduces network congestion
  • Enhances security by segmenting traffic
• How to Subnet

  Determine subnet mask, calculate subnets, assign addresses, and configure routers/interfaces
• Types of Subnetting Problems

  • Subnetting when given a required number of networks
  • Subnetting when given a required number of clients
  • Given an IP address & Subnet Mask, finding original network range (reverse engineering a subnet problem)