Architecture of WLAN Flashcards
Radio Card Formats?
PCMCIA CF SD PCI Mini-PCI PCI Express USB
Radio Card Chip Sets?
Integrated Circuits
May support Functions, Frequencies, Protocols
Often Proprietary
Progression of WLAN Architecture?
Autonomous AP WNMS Centralized WLAN Architecture Lightweight AP WLAN Controller Split MAC Remote Office WLAN Controller
Management Plane?
Defined by administrative network management, administration, and monitoring
Control Plane?
Consists of control or signaling information and is often defined as network intelligence or protocols
Data Plane?
Also known as the user plane, is the location in a network where user traffic is actually forwarded.
802.11 Management Plane?
WLAN Configuration
WLAN Monitoring and Reporting
WLAN Firmware Management
802.11 Control Plane?
Dynamic RF
Roaming Mechanisms
Client Load Balancing
Mesh Protocols
802.11 Data Plane?
Where user data is forwarded
Devices that usually participate in the data plane are the AP and a WLAN controller
Each vendor has a unique method and recommendations for handling data forwarding
Management Plane Functions
WLAN Configuration
Examples of WLAN Configuration?
SSIDs Security WMM Channel Power Settings
WLAN Monitoring and Reporting?
Monitoring of layer 2 statistics like: ACKs, Client Associations, Resassociations, Data Rates.
Examples of Upper layer monitoring and reporting includes:
Ip connectivity
TCP Throughput
Latency statistics, and
Stateful Firewall Sessions
WLAN Firmware Management?
The ability to upgrade access points and other WLAN devices with the latest vendor operational code
Control Plane Functions?
Dynamic RF
Roaming Mechanisms
Client Load Balancing
Mesh Protocols
Dynamic RF?
Coordinated channel and power settings for multiple access points.
Radio Resource Management
Roaming Mechanisms?
Support for roaming handoffs between access points
Capabilities may include
- L3 Roaming
- Maintaining stateful firewall sessions of clients
- Forwarding of buffering packets
Client Load Balancing?
Collecting and sharing client load and performance metrics between access points to improve overall WLAN operations
Mesh Protocols?
Routing user data between multiple access points requires some sort of mesh routing protocol.
The 802.11s amendment has defined standardized mesh routing merchanism but most WLAN vendors are currently using proprietary methods and metrics
Data Plane Function?
The data plane is where user data is forwarded
The two devices that usually participate in the data plane are the AP and a WLAN controller.
Autonomous APs handle all data forwarding operations locally.
In a WLAN controller solution, data is normally forwarded from the centralized controller, but data can also be forwarded at the edge of the network.
Three primary WLAN architectures?
Autonomous WLAN Architecture
Centralized WLAN Architecture
Distribtuted WLAN Architecture
Autonomous AP?
Once called fat AP May Provide Additional Services No Controller required Multiple Management Interfaces Multiple Mode Support Found in SOHO and Enterprise Networks
Features of Autonomous AP
Multiple management interfaces WEP, WPA, WPA2 WMM QoS capabilities Fixed or detachable antennas Filtering options, such as MAC and protocol Removable radio cards
Advanced Features of Autonomous AP
Built-in RADIUS and user databases
VPN Client and/or server support
DHCP Server
Captive Web Portals
WNMS?
Wireless Network Management System?
Wireless Network Management System?
Provides a central point of management to configure and maintain thousands of autonomous access points
Hardware appliance or a software solution
Centralize Wlan Architecture?
Uses a central WLAN controller Uses lightweight (Thin) APs May use adaptive APs All intelligenceq resides in controller Encryption may be controller or AP based
Lightweight AP
Also called thin AP
Also called controller based AP
WLAN Controller Planes?
Management Plane
Control Plane
Data Plane
WLAN Controller Functions?
AP Management 802.11 Traffic Tunneling AP Group Profiles WLAN Profiles Virtual BSSIDs VLAN User Management Layer 2 Security Support
