5.4

Question 1

Whats is reflection?

Answer 1

It’s an issue that can be cause in wireless networks which is when wireless signals can bounce off some surfaces(i.e., metal, desks) Too much reflection can weaken the signal.

Question 2

How can we resolve reflection?

Answer 2

By positioning the antennas to avoid excessive reflection.

Question 3

What is refraction?

Answer 3

It’s when signal passes through an object and exits at a different angle(like light in water). It can affect data rates.

Question 4

What is absorption?

Answer 4

It’s when signal passes through an object and loses signal strength(like walls and windows)

Question 5

What is latency?

Answer 5

Delay between transmission and reception.

Question 6

What is jitter?

Answer 6

It’s deviation from a predictable data stream(mostly in VoIP).

Question 7

When does capacity issue occur?

Answer 7

It happens when many people are using the same wireless frequencies.

Question 8

What is attenuation in wireless network?

Answer 8

It’s when wireless signals get weaker as you move farther from the antenna.

Question 9

How do we fix attenuation?

Answer 9

1. We can control and boost the power output on the access point.
2. Use a receive antenna with a higher gain.
3. Move closer to the antenna

Question 10

What is interference? and what are the different kinds?

Answer 10

It’s when something else is using our frequency.
1. Predictable(Florescent light, microwave ovens)
2. Unpredictable(multi-tenant building.
But to measure the interference we can use “netstat -e” or use a performance monitor.

Question 11

Based on what do we choose our antenna?

Answer 11

Based on the room. The antenna must fir the room.

Question 12

How many kinds of antennas do we use?

Answer 12

1. Omnidirectional(useful on the ceiling,but not useful between buildings.
2. Directional(Used often between two points)

Question 13

How can an incorrect antenna placement affect the wireless network?

Answer 13

1. Interference
2. Slow throughput
3. Check access point locations and channel settings.

Question 14

What is channel overlapping?

Answer 14

Channel Overlap is a result of Radio Frequencies having to share a medium (wireless) located within the same area.

Question 15

What kind of problems does overcapacity cause?

Answer 15

Overcapacity usually happens in large meeting places(airports, hotels)

1. Device saturation(too many devices on one wireless network)
2. Bandwidth saturation(Large data transfers)

Question 16

When does frequency mismatch happen?

Answer 16

When devices frequencies don’t match the access point(2.4GHz, 5GHz)

Question 17

Why is the signal to noise ratio important?

Answer 17

Signal is what we want, but noise is what we don’t want(interference from other networks and devices). We always want a very large ratio(the same amount of signal to noise(1:1) would be bad.)