Networking Fundamentals

Switching

• A switch is a network device that connects multiple devices within a network
• Switches operate at the data link layer (Layer 2) of the OSI model
• Switches forward frames based on MAC addresses
• Types of switches:
  • Unmanaged switches: simple, no configuration options
  • Managed switches: configurable, with features like VLANs and QoS
  • PoE (Power over Ethernet) switches: provide power to devices over Ethernet cables

TCP/IP

• TCP/IP (Transmission Control Protocol/Internet Protocol) is a suite of communication protocols used to interconnect devices on the internet
• TCP/IP is the standard protocol used for internet communication
• Key components of TCP/IP:
  • IP (Internet Protocol): responsible for addressing and routing packets
  • TCP (Transmission Control Protocol): ensures reliable, error-checked data transfer
  • UDP (User Datagram Protocol): ensures fast, best-effort data transfer
  • ICMP (Internet Control Message Protocol): used for error-reporting and diagnostic functions
  • DNS (Domain Name System): translates domain names to IP addresses

Subnetting

• Subnetting is the process of dividing a larger network into smaller, more manageable sub-networks
• Subnetting allows for more efficient use of IP addresses and improved network organization
• Key subnetting concepts:
  • Subnet mask: a 32-bit number that determines the scope of a subnet
  • Subnet ID: the unique identifier of a subnet
  • Host ID: the unique identifier of a device on a subnet
  • CIDR (Classless Inter-Domain Routing) notation: a shorthand way to represent subnets and IP addresses

Routing

• Routing is the process of forwarding packets between networks
• Routers operate at the network layer (Layer 3) of the OSI model
• Key routing concepts:
  • Routing tables: store information about reachable networks and the best path to reach them
  • Routing protocols: algorithms used to update routing tables and determine the best path
  • Static routing: manual configuration of routing tables
  • Dynamic routing: automatic updating of routing tables using routing protocols

Network Security

• Network security refers to the measures taken to protect a network from unauthorized access, use, disclosure, disruption, modification, or destruction
• Key network security concepts:
  • Firewall: a network device or software that controls incoming and outgoing network traffic
  • Authentication: the process of verifying the identity of a user or device
  • Authorization: the process of determining what actions a user or device can perform on a network
  • Encryption: the process of converting plaintext data into unreadable ciphertext
  • VPN (Virtual Private Network): a secure, encrypted connection between two endpoints over the internet