14 - Network Devices - 2.5

Introduction to Networking Devices

  • Overview of networking components in a data center or computer room.

    • Rack structures housing various devices, servers, components.

    • Unique roles and functions for each device within the network.

Network Component Functionality

  • Combination of standalone devices into singular units.

    • Example: Home Internet connectivity through a wireless router

    • Combines router, switch, access point, and security software.

Types of Network Devices

Routers

  • Definition: Devices making forwarding decisions based on destination IP addresses in packets.

    • Routers utilize internal tables for traffic direction based on destination IP.

  • Usage

    • Connects different IP subnets and various network types (e.g., Ethernet, wireless).

    • Functions across OSI layer 3.

  • Layer 3 Switches

    • Definition: Devices that combine routing and switching capabilities.

    • Often used in organizational networks to improve efficiency of different network types.

Switches

  • Definition: Connect end devices and manage traffic using destination MAC addresses.

  • Characteristics

    • Operate at high speeds using application-specific integrated circuits (ASIC).

    • Typically found in various configurations, such as workgroup switches with 24 or 48 ports.

  • Types of Switches

    • Unmanaged Switches

    • Characteristics

      • Simple plug-and-play setup, no configuration necessary.

      • Entire device operates as one VLAN.

      • Lower cost due to lack of flexible options.

    • Managed Switches

    • Characteristics

      • Configurable and remotely manageable; allows for advanced settings (e.g., VLANs, traffic prioritization).

      • Redundancy support to mitigate failures.

      • Port mirroring functionality for security monitoring and analysis.

Access Points

  • Definition: Wireless networking devices that bridge wired and wireless networks.

  • Functionality

    • Operates similarly to switches by evaluating destination MAC addresses.

    • Facilitates wireless to wired communication without performing routing functions.

Patch Panels

  • Structure

    • Managed centralized points in closets allowing for network cable organization.

    • RJ45 connectors on one side to link to switches, providing manageability for Ethernet connections.

  • Functionality

    • Facilitates easy modifications to switch connections without disturbance to desk connections.

  • Benefits

    • Simplifies cable management and troubleshooting processes.

Security Devices

Firewalls

  • Traditional Firewalls

    • Make decisions based on port numbers (TCP/UDP) and access lists.

  • Next-Generation Firewalls

    • Based on application data rather than port numbers.

    • Can operate as VPN concentrators and proxies.

    • Installations often as routers to manage traffic between subnets.

Power Distribution in Networking

Power over Ethernet (PoE)

  • Definition: Technology transmitting both power and data over Ethernet cables.

  • Applications

    • Used to power devices like IP phones and access points.

  • Types of PoE

    • Standard PoE: 15.4 watts, max current 350 milliamps.

    • PoE Plus: 25.5 watts, max current 600 milliamps; suitable for more demanding devices (e.g., cameras).

    • PoE Plus Plus: 51 watts to 71.3 watts for power-hungry devices with higher current ratings.

  • Terminology

    • Inspan: PoE from the switch.

    • Midspan: PoE from an injector.

Internet Connectivity Methods

Cable Modems

  • Use broadband over coax cables for data transmission.

  • Also referred to as DOCSIS (Data Over Cable Service Interface Specification).

  • Commonly support high data throughput, found in corporate and home networks.

Digital Subscriber Line (DSL)

  • Utilizes existing phone lines for digital signal transmission.

  • Typical throughput: 200 Mbps downstream, 20 Mbps upstream with limitations based on distance from the service distribution point (10,000 feet).

Fiber Connectivity

  • Optical Network Terminal (ONT)

    • Converts fiber optic signals to copper for traditional networking use.

    • Acts as a demarcation point defining user vs. service provider responsibilities.

Network Interface Cards (NICs)

  • Provide Ethernet connectivity through system boards in devices or as separate expansion cards.

  • Various types based on speed capabilities (e.g., 100 Mbps, gig Ethernet).

  • Each interface has a unique media access control (MAC) address for network identification.