Networks -- Additional Notes #1

Page 1: Important Devices in Wireless Networking

Network Interface Card (NIC)

• A Network Interface Card (NIC) is essential for connecting to a network.

• Functions of a NIC:

  • Necessary for devices to access the network.

  • Enables sending and receiving data over a network, both wired and wireless.

  • Operates at both the physical and data link layers.

  • Each NIC has a unique physical MAC address used at the data link layer.

Types of NICs:

• Internal Network Cards:

  • Inserted into a motherboard slot; require network cables.

  • Types: PCI (Component Interconnect) and ISA (Industry Standard).

• External Network Cards:

  • Used in desktops/laptops lacking internal NICs; can be wireless or USB-based.

  • Wireless cards do not require cables.

Wireless Access Points (WAPs)

• A Wireless Access Point (WAP) provides Wi-Fi access to a wired network.

• Key functions:

  • Connects wireless devices (laptops, smartphones) to a wired LAN.

  • Extends the physical range of a network without cables.

Page 2: WAPs Continued

Coverage Expansion

• WAPs increase the coverage area of a wireless network and eliminate dead spots.

• Properly placed APs ensure extensive wireless coverage in large spaces.

Network Management

• WAPs can increase network performance when multiple devices are connected.

• Offer security features to ensure only authorized devices connect to the network.

DHCP Server Functionality

• Some WAPs can automatically assign IP addresses to connecting devices.

Modes of Access Point Devices:

• Access Point Mode: Connects wireless and wired networks via Ethernet.

• Repeater Mode: Extends wireless signals while maintaining network security.

• Client Mode: Used on devices with Ethernet ports, like PCs.

• Bridge Mode: Creates an independent network using one internet connection.

• Wireless Router Mode: Shares internet connections to multiple clients simultaneously.

Types of APs:

• Standalone AP: Commonly used in larger networks (offices/schools).

• Multifunction AP: Combines multiple networking features (wireless connectivity, routing, etc.).

• Controlled AP (LWAP): Works with a central Wireless LAN Controller, offloading tasks to it.

Applications of Access Points:

• Increase device capacity in networks with limited router support.

• Ensure full connectivity throughout office spaces.

• Enhance signal range and strength of WLANs.

Page 3: Routers and Networking Concepts

Routers

• Routers connect different networks, especially between a LAN and the internet.

• Operate at the network layer (Layer 3) of the OSI model.

• Wireless routers provide additional features:

  • Routing between networks.

  • Firewall protection.

  • Built-in Ethernet switch capabilities.

Router Configuration

• More complex; requires settings for:

  • Network addressing

  • NAT (Network Address Translation)

  • Port forwarding

  • Firewall rules

Intranet vs. Extranet

• Intranet:

  • A private network for organization staff.

  • Facilitates internal communication, collaboration, and information sharing.

  • Hosts internal services (forums, search engines, databases).

• Extranet:

  • An extension of the intranet, allowing controlled access to outsiders.

  • Facilitates business-to-business communication.

  • Can implement security measures (firewalls, encryption).

Key Differences

• Intranet is for internal use by employees; extranet extends access to selected external users.

• Both systems are critical for modern business operations, enhancing communication and collaboration across various levels.