13. RRM

Question 1

Where in the web GUI do you globally configure the data rates for the 2.4GHz and 5GHz radios.

Answer 1

Wireless > 802.11a/n/ac > Network

Wireless > 802.11b/g/n > Network

Question 2

What are the default data rates set to mandatory on a controllers 2.4GHz radios?

Answer 2

1 Mps
2 Mps
5.5 Mps
11 Mps

Question 3

What are the default data rates set to mandatory on a controllers 5GHz radios?

Answer 3

6 Mps
12 Mps
24 Mps

Question 4

RRM can make what types of decisions about APs in an RF group?

Answer 4

Transmit power control (TPC)
Dynamic channel allocation (DCA)
Coverage hole detection mitigation (CHDM)

Question 5

By default, TPC and DCA algorithms run how often?

Answer 5

600 seconds (10min)

Question 6

Transmit power control has two versions what are they and which is the default

Answer 6

Coverage optimal mode (v1 - default)

Interference optimal mode (v2)

Question 7

There are three power level assignment methods in TPC. What are they and what do they do?

Answer 7

Automatic 
    (runs algorithm at a given interval)
On Demand 
    (run algorithm once and levels 
     stay at those levels)
Fixed
    (set a tx power and all APs are
     set to that value)

Question 8

Does TPC run independently on 2.4GHz and 5GHz?

Answer 8

Yes

Question 9

There are 8 transmitter power levels that can be set on the 2.4GHz and 5GHz radios. What are the dBm value for level one and how can you figure out the rest?

Answer 9

Level 1 23 dBm
Each level is 3 dBm less (half the power) than the previous
Note: Level 7 and 8 are not used in 5GHz

Question 10

What are the 3 conditions that are enabled by default that would cause DCA (Dynamic Channel Allocation) to move an AP to another channel?

Answer 10

Co-channel interference
802.11 interference
Non-802.11 noise

Question 11

CHDM (Coverage Hole Detection Mitigation) is useful in what two cases?

Answer 11

Extending coverage in a weak area

Rapidly healing coverage due to AP or radio failure

Question 12

By default, what are the conditions that must all be met for a coverage hole to be detected?

Answer 12

1. Client RSSI at the AP is at or below -80 dBm
2. The low RSSI condition must last at least 60 seconds over the last 180 seconds
3. The condition must affect at least 3 clients or more than 25% of the clients on a single AP

Question 13

TPC and DCA operate on the entire RF group of controllers. How does CHDM differ?

Answer 13

CHDM runs on each controller independently, on a per-AP basis.

Question 14

Can you override TPC and DCA on a specific AP?

Answer 14

Yes