šŸŒ

Overview of Network Devices and Their Functions

Sep 21, 2024

Key Concepts in Network Infrastructure

Types of Network Devices

Single-use and Multi-function Devices

  • Single-use Devices: E.g., switches.
  • Multi-function Devices: E.g., SOHO routers that incorporate switch, router, and wireless access point functionalities.

Routers

  • Function: Forwards traffic between IP subnets using IP addresses in packets to determine the next hop.
  • OSI Model: Operates at Layer 3 (Network Layer), hence called Layer 3 devices.
  • Layer 3 Switches: Routers configured inside of a switch.
  • Connectivity: Connects different network types like LAN, WAN, copper, and fiber.

Switches

  • Function: Forwards traffic based on destination MAC address inside frames.
  • Hardware: Often equipped with ASICs for high-speed forwarding.
  • Power Over Ethernet (PoE): Provides power and data through Ethernet cables.
  • Managed vs. Unmanaged Switches:
    • Managed: Offers configuration options like VLANs, traffic prioritization, spanning tree protocol (STP), port mirroring, and SNMP.
    • Unmanaged: Simple connectivity, no VLAN or SNMP capabilities.

Access Points

  • Function: Connects wireless networks to wired networks, often referred to as a bridge.
  • Operation: Forwards data using MAC addresses, similar to switches.

Patch Panels

  • Purpose: Connects devices to main network infrastructure, simplifying cable management.
  • Configuration: Permanent run from desk to panel, flexible connections from panel to switch.

Firewalls

  • Traditional Firewalls: OSI Layer 4 devices based on IP addresses and port numbers.
  • Modern Firewalls: Layer 7 devices that understand application traffic.
  • Functions: May include encrypted tunnels, proxy services, and routing (Layer 3).

Power over Ethernet (PoE)

  • Types:
    • IEEE 802.3af (2003): 15.4 watts, 350 mA max current.
    • IEEE 802.3at (2009): 25.5 watts, 600 mA max current.
    • PoE++ (IEEE 802.3bt): Up to 71.3 watts, supports 10 Gb/s Ethernet.
  • Devices: Wireless access points, cameras, etc.

Hubs

  • Function: Multi-port repeaters, inefficient data transmission.
  • Operation: Half-duplex, retransmits data to all ports.
  • Status: Outdated, replaced by switch-based networks.

Modems

  • Cable Modems: Use broadband communication, support multiple frequencies, DOCSIS standard.
  • DSL Modems: ADSL, asymmetric speeds, distance limitations from central office.
  • Fiber Networks: Use ONTs (Optical Network Terminals) for conversion to copper Ethernet.

Network Interface Cards (NICs)

  • Purpose: Connect devices to network via various topologiesā€”copper, fiber, or wireless.
  • Types: Built-in or add-on cards for servers and desktops.

Conclusion

Understanding the different network devices and their purposes is crucial for network planning and troubleshooting. Each device type has specific functionalities and use cases, which are essential for effective network management and infrastructure design.

Full transcript