CWDP Notes (CWDP-302)
Chapter 1: Introducing WLAN Design
Design Process
- Define
- Design
- Implement
- Validate
Chapter 2: Requirements Analysis
A requirement is anything that must be provided by the product or outcome of the project.
Business requirements are known as the objectives of the organization.
User requirements include the goals or tasks that users must perform when using the WLAN.
Technical requirements allow the WLAN to meet user and business requirements.
Regulatory requirements are those imposed by policies or government agencies.
Information gathering is a four phase process including elicitation, analysis, specification, and validation.
Client devices and applications must be considered when planning a WLAN.
Security requirements should be defined including authentication, encryption, and monitoring.
Physical coverage requirements are essential as the WLAN must serve the users where they require service.
Building factors should be discovered including building materials, square footage and the gathering of blueprints and acquiring facility access for the site survey when required.
Chapter 3: Site Survey Procedures
Three basic survey types
- Manual – also called AP-on-a-stick
- Predictive – software to simulate RF behavior
- Hybrid
Primary tools used for wireless network analysis are protocol and spectrum analyzers. Protocol analyzers locate WLANs and the configuration parameters of them which are revealed through the beacon frames. Spectrum analyzers can locate both Wi-Fi and non-Wi-Fi devices that may cause issues on specific channels.
It is important to remember to calibrate the software after importing a floor plan. This process involved selecting a long-distance range on the floor plan that has a known distance in reality and entering that distance into the software. This step allows the software to ensure proper calibration for RF signal coverage.
Co-channel interference (CCI) is caused by two or more APs existing on the same channel in close proximity to each other.
Adjacent channel interference (ACI) is caused when a near cell is using an adjacent channel.
VoIP requires low latency and low jitter with low packet loss of less than 1 percent.
Chapter 4: Enterprise WLAN Design
WLAN Architectures
Management Solutions
- Controller-based
- Cloud-based
- Autonomous
802.11 QoS
- AC_BK – Background – lowest priority
- AC_BE – Best Effort – lowest priority
- AC_VI – Video – middle priority
- AC_VO – Voice – highest priority
When an AP tunnels to a controller with centralized data forwarding, the WLAN controller converts DSCP values to 802.1Q user priority tags or 802.1p tags.
Chapter 5: Advanced WLAN Design
The beamwidth is calculated where the signal reaches half power or –3dB or half power.
Antenna Types
- Omni-directional
- Patch/panel
- Yagi
- Sector
- Parabolic dish
Azimuth charts show the propagation pattern from a top-down perspective. Elevation charts show the propagation pattern from a side perspective.
Chapter 6: WLAN Deployment
In many RRM implementations, APs go off channel for a period of time, typically less than 100 ms, to monitor other channels for noise and interference.
Chapter 7: Design Validation
Application validation can be performed using site survey software, throughput testers, and the actual applications themselves.
Proper coverage is measured in signal strength, such as dB or RSSI.