Troubleshooting Wireless Issues

Question 1

What is the RSSI? In what is it measured?

Answer 1

The Received Signal Strength Indicator (RSSI) is an estimated measure of the power level that a radio frequency client device is receiving from an access point.
Its measured in Decibel milliwatt (dBm).

Question 2

What is the EIRP? In what is it measured?

Answer 2

The Effective Isotropic Radiated Power (EIRP) is the maximum amount of power that could be radiated given the antenna gain the the transmitter power.
Its measured in Decibels over isotropic (dBi).

Question 3

What technology/configuration allows to add additional access points to the same network to extend coverage?

Answer 3

Extended Service Set (ESS)

Question 4

For 5GHz WiFis: When using a honeycomb pattern for the access point placements, what is important?

Answer 4

If you choose a channel multiple times, other access points with that channel need to be at least 2 zones away.

Question 5

What is Multipath Reception?

Answer 5

It means that the signal from an access point bounces off walls, often more than once, before it reaches the receiver which attenuates the signal.

Question 6

What are the 6 reasons for client disassociation?

Answer 6

1. Idle Timeout Disassociation: Client inactive for 300s
2. Session Timeout Disassociation: Client inactive for 1800s
3. Wireless Network Changes
4. Manual Deletion: Client gets removed by an admin
5. Authentication Timeouts: Client didnt complete auth in a given time
6. Access Point Radio Resets

Question 7

What are Captive Portals?

Answer 7

Captive Portals are the Confirmation or Login Pages you see when connecting to public WiFis.

Question 8

What are the 3 steps to solve captive portal issues?

Answer 8

1. Open a browser and go to a reliable site.
2. Determine the default gateway IP of the network and open it in the browser.
3. Verify the DNS server IP you are using and allow DHCP autoconfiguration.

Question 9

What is polarization?

Answer 9

It refers to the orientation of the electromagnetic waves that the antenna sends or receives. Most WiFi clients with external antennas use vertical polarization.

Question 10

What is Channel Untilization and whats the best value? What is a big problem with access points on the same channel?

Answer 10

Its the measure of the amount of airtime utilization of a specific frequency or channel.
Access points and clients on the same channel create a single broadcast domain,
It should be under 30%.

Question 11

What is CCA?

Answer 11

Clear Channel Assessment (CCA) listens on the channel to see if another device is transmitting before it sends data.

Question 12

How many steps does the Wireless client association process involve?

Answer 12

7