Network Devices

 Network Devices

HUB




  • Hardware device
  • Open standard
  • Non-manageable device
  • Provides continuous broadcasting (sends data to all ports) Works on Physical Layer (Layer 1) of the OSI Model
  • No MAC learning capability
  • Single collision domain and single broadcast domain
  • Half-duplex communication
  • Obsolete (not used in modern networks due to inefficiency)

SWITCH


  • Intelligent device
  • Works on MAC addresses
  • Operates on Layer 2 (Data Link Layer) of the OSI Model
  • Used to create and manage LAN networks

Ethernet Family

  • Ethernet – 10 Mbps
  • Fast Ethernet – 100 Mbps
  • Gigabit Ethernet – 1 Gbps
  • 10 Gigabit Ethernet – 10 Gbps (corrected from Terabit)
MAC Address
  • Hexadecimal format (0–9, A–F)
  • 48-bit address (6 bytes)
  • Each hex value = 4 bits

Example: A1:B2: C3:D4: E5:F6

  • First 24 bits → OUI (Organizationally Unique Identifier)
  • Last 24 bits → NIC specific (device identifier)

Key Features of Switch

  • Maintains MAC Address Table (CAM Table)
  • Reduces collisions (each port = separate collision domain)
  • Full-duplex communication
  • Supports VLAN (Virtual LAN)
  • Supports STP (Spanning Tree Protocol) to prevent loops
  • Managed and Unmanaged switches available

NIC (Network Interface Card)


  • Hardware component used to connect a device to a network
  • Can be wired (Ethernet) or wireless (Wi-Fi)
  • Each NIC has a unique MAC address
  • Works at Layer 1 and Layer 2

ROUTER


  • Works on Network Layer (Layer 3) of the OSI Model
  • Open standard device
  • Uses IP addresses for communication
  • Connects multiple networks (LAN to LAN or LAN to WAN)
Key Functions
  • Routing (path selection)
  • Packet forwarding
  • Inter-VLAN Routing
  • NAT (Network Address Translation)
  • DHCP (in small networks)
  • Each interface = separate broadcast domain

FIREWALL


  • Security device (can be hardware or software)
  • Filters traffic based on rules (Allow/Deny)

Types of Firewalls

  • Packet Filtering Firewall
  • Stateful Firewall
  • Next-Generation Firewall (NGFW)

Key Features

  • Access Control (ACLs)
  • VPN support
  • Intrusion Prevention (IPS in NGFW)
  • Application-level filtering

MLS (Multi-Layer Switch) 


  • Combines switching + routing
  • Works on Layer 2 and Layer 3
  • Provides high-speed routing within LAN

Key Features

  • Inter-VLAN routing (faster than router)
  • Supports routing protocols (OSPF, EIGRP, etc.)
  • Used in core and distribution layers


Feel free to share this information with others who are learning, and don’t forget to check out my channel TechWithYourFriend for more hands-on networking videos.

www.youtube.com/@TechWithYourFriend





Location: New Delhi, Delhi, India

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