Implementing Inter-VLAN Routing and WLAN Security Standards

Inter-VLAN Routing: Router-on-a-Stick Configuration

Router-on-a-Stick is a router configuration type used for forwarding network traffic between multiple Virtual Local Area Networks (VLANs) using a single physical interface.

The router performs inter-VLAN routing by accepting traffic labeled with VLAN tags (using a trunk interface from the adjacent switch) and routing internally between virtual interfaces (subinterfaces).

Configuring Subinterfaces and Multilayer Switches

Subinterfaces are multiple logical interfaces associated with a single physical interface. To enable a multilayer switch to perform routing functions, you must configure the VLANs on the switch interfaces with corresponding IP addresses that match the subnet associated with that VLAN.

If switch ports are not properly configured for the correct VLAN, devices configured within that VLAN cannot connect to the router interface and, consequently, cannot route traffic to other VLANs.

The routing process requires the source device to determine if the target device is local or remote based on the local subnet address.

Link Aggregation and Network Verification

Ethernet Channel (Link Aggregation)

Ethernet Channel allows you to aggregate multiple physical links into a single logical link. This technology can provide significant aggregated bandwidth, potentially up to 80 Gbps when using 10 Gigabit Ethernet links.

Essential Verification Commands

The following commands are useful for identifying VLAN assignments, port configuration issues, and verifying switch settings:

• show running-config: Displays the current configuration of the device.
• show interface [interface-id] switchport: Verifies the switch port settings, including VLAN assignment and trunking status.
• show ip interface brief: Displays the status and IP addresses of interfaces.

Wireless Local Area Networks (WLAN) Fundamentals

The standard IEEE 802.11 wireless network uses modulation techniques for setting and encoding a stream of data over a wireless Radio Frequency (RF) signal.

A Network Interface Card (NIC) often plays the role of an Access Point (AP) in small setups, providing a gateway to connect to other wireless network infrastructures.

Key WLAN Influencers

The three key organizations influencing WLAN standards worldwide are:

1. ITU-R (International Telecommunication Union – Radiocommunication Sector)
2. IEEE (Institute of Electrical and Electronics Engineers)
3. Wi-Fi Alliance

WLAN Security and Threats

There are three major categories of threats leading to unauthorized access:

• Open wireless networks (unsecured access points).
• Hackers (external malicious actors).
• Employees (internal misuse or negligence).

Wireless security protocols like EAP (Extensible Authentication Protocol) and encryption are used to meet stringent network security requirements, ensuring authentication before connection.

Enterprise Encryption Mechanisms (IEEE 802.11)

The two primary enterprise encryption mechanisms used in IEEE 802.11 are:

1. TKIP (Temporal Key Integrity Protocol)
2. AES (Advanced Encryption Standard)

Basic Wireless Network Configuration Focus

For the basic configuration of a wireless network, focus on the following points:

• Access Point configuration management.
• Administered wireless security permissions for connection.
• Signal distribution optimization.

Access Point Firmware Update Procedure

To ensure optimal performance and security, follow these steps to update the Access Point firmware:

1. Download the firmware file from the manufacturer's website.
2. Extract the firmware file on your computer.
3. Open the web-based utility (management interface) and navigate to the appropriate section (often labeled "System" or "Administration").
4. Select the Firmware Update option.
5. Enter the location of the firmware file or click the Browse button to locate the file.
6. Click the Start Update button and follow any subsequent instructions.