5.1 Wireless LAN Mobility

Wireless LAN Mobility refers to the ability of devices to maintain network connectivity as they move within a wireless network. This section will explore key concepts related to WLAN mobility, providing detailed explanations and practical examples to enhance your understanding.

Key Concepts

• Roaming: The process of a client device switching from one Access Point (AP) to another while maintaining network connectivity.
• Handoff: The specific event when a client device transitions from one AP to another.
• Fast Secure Roaming (FSR): A method that ensures seamless and secure handoffs between APs.
• Mobility Groups: A collection of APs and controllers that work together to provide seamless roaming across multiple locations.
• Load Balancing: Distributing client connections evenly across multiple APs to prevent overloading and ensure optimal performance.

Detailed Explanation

Roaming

Roaming is the process by which a client device switches from one AP to another while maintaining network connectivity. This ensures that users can move freely within a wireless network without experiencing interruptions in service. Roaming is essential for large environments such as campuses, airports, and corporate offices.

Example: In a university campus, students with laptops can move from one building to another while staying connected to the internet. As they move out of range of one AP and into range of another, the device seamlessly switches to the new AP, maintaining continuous connectivity.

Handoff

Handoff is the specific event when a client device transitions from one AP to another. This process involves several steps, including signal strength monitoring, AP selection, and authentication. A smooth handoff is crucial for maintaining a seamless user experience.

Example: In an airport, a passenger with a mobile device is walking through the terminal. As they move from one section to another, their device detects a weaker signal from the current AP and a stronger signal from a nearby AP. The device then initiates a handoff to the new AP, ensuring uninterrupted internet access.

Fast Secure Roaming (FSR)

Fast Secure Roaming (FSR) is a method that ensures seamless and secure handoffs between APs. FSR uses protocols like 802.11r and 802.11k to reduce the time required for handoffs and maintain security. This is particularly important for real-time applications like VoIP and video conferencing.

Example: In a corporate environment, employees use VoIP phones that require continuous connectivity. FSR ensures that when an employee moves from one office to another, the VoIP phone quickly and securely hands off to a new AP, maintaining clear and uninterrupted voice communication.

Mobility Groups

Mobility Groups are collections of APs and controllers that work together to provide seamless roaming across multiple locations. This is useful for organizations with multiple sites, such as retail chains or distributed campuses.

Example: A retail chain has stores in multiple cities. By configuring APs and controllers into a mobility group, the IT team ensures that customers with mobile devices can move between stores and maintain continuous connectivity, enhancing the shopping experience.

Load Balancing

Load balancing involves distributing client connections evenly across multiple APs to prevent overloading and ensure optimal performance. This is crucial for maintaining a high-quality user experience, especially in high-density environments.

Example: In a large conference hall, hundreds of attendees have mobile devices connected to the WLAN. Load balancing ensures that no single AP becomes overwhelmed, distributing the connections evenly across multiple APs to maintain fast and reliable internet access for all users.

By understanding these key concepts of Wireless LAN Mobility, you will be well-equipped to design, implement, and manage a seamless and efficient wireless network.