Wireless Analysis 101

September 10, 2018

Wireless Performance Analysis

I want to jot down some points for my own revision and yours if they may help you in getting through a wireless performance analysis for any business/firm.

Intention : To conduct wireless analysis without gaining access to the network equipment of the firm.

Software/App used or required – Spectrum Analyser – from Metageek https://www.metageek.com/products/

https://www.metageek.com/products/wi-spy/

Environments tested: Cisco and Fortinet

Client: Macbook which has built-in channelyzer

#RULES

Always have two tools to verify your finding.

#Approach

Client roaming between Access Points
Baseline current performance and airtime utilization. Use this as normal.
- Current Hardware – Identify the client hardware/driver etc
- 802.11 scan
- Spectrum Analysis
Baseline efficiency performance and airtime utilization. Operate performance testing.
- During testing, scan the packets and look for inefficiencies
Performance 1-1 wireless to wireless, wireless to wired etc.
Performance over the internet.

Select your preferred 802.11 scanners e.g. Spectrum Analyser
Performance tools
1. Fast.com – ONLY DOWNLOAD
2. Speedtest.net D/UPLOAD
3. Hotelwifitest.com – This is new, more concentrated toward hospitality(hotel), event scenarios.

Pick 3-4 locations on the floor map. Preferably random areas on the floor map and conduct your testing.

802.11 scan – Minimum 2 APs with strong signal strength – Verify if this is the case from all the locations using the SA tool.
Spectrum Analysis – Identify sources of interference on 2.4GHz and 5GHz. TIP: Check duty cycle. In most cases a duty cycle of 10% or less is acceptable.
Packet Scan on Channels – Packet scan on 2.4GHz (1,6 and 11) and 5GHz in the areas – This was done using the built-in tool on Mac. Collect each channel date for 2-3 minutes max. Analyse each collected PCAP on a spectrum analyser and check for data/management/control plane utilization – https://www.letstalk-tech.com/how-to-access-the-wifi-scanner-in-mac-os-x-yosemite/
Performance Test: Conduct 3 tests on each of the websites mentioned above.
WLC Review if available (Run the show run configuration and check advanced radio summary

TIP: Refer to http://mcsindex.com/ – The MCS index value list gives every combination of “number of spatial streams + modulation type + coding rate” that is possible. In practice, the achievable MCS value will depend on a large number of variables, and it may be prudent to run your hardware at a lower MCS value on purpose in order to allow for adequate fade margin in your link. The MCS value will only tell you the ‘over the air’ data rate of a link and not tell you what the actual usable throughput will be. You will need to refer to the documentation of your hardware for this information.