What's the difference of coverage hole and pre-coverage hole?

Answered Question
Sep 20th, 2010

Hi All,

Anybody knows what's the difference of coverage hole and pre-coverage hole?

What I can find from Cisco doc is:

"coverage holes are displayed as alarms, pre-coverage holes are displayed as events."

"Gaps or "holes" in an access point radio coverage are the primary cause of poor audio. Client-detected Pre-Coverage Hole events provide ongoing monitoring to ensure that the customer is alerted regarding the existence of these coverage holes."

It seems Pre-coverage hole is client-detected, coverage hole is AP detected? However I'm not sure.

Another question is which trap includes pre-coverage hole alarm in WCS 7.0 alarm and event dictionary? I can only find several coverage related traps:

LRADIF_COVERAGE_PROFILE_FAILED

LRADIF_COVERAGE_PROFILE_PASSED

However both of them have not say if it is for coverage hole or pre-coverage hole. Not sure which trap will be sent by the WCS to a configured notification receiver to indicate a pre-coverage hole event, for example:

Minor         --X----       13:27:52 16/09/10    cisco-WCS     WCS    SNMP   <$2>   0x07 da 09 10 0d 1b 2c 05 2b 0a 00 :10.1.1.12 : Pre-Coverage Hole reported by 00:1f:3c:cd:c8:2a detected by 10.1.1.12: Pre-Coverage Hole reported by '00:1f:3c:cd:c8:2a' was found on Controller

Your valuable input is highly appreciated!

I have this problem too.
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Correct Answer by Nicolas Darchis about 6 years 1 month ago

Hello !

A pre-coverage hole is when a client stays for 5 seconds in a coverage hole. In other words, when a client is heard for some time at bad signal and it's not roaming, it must mean that this area is a coverage hole. This event is informational

A coverage hole event is when several clients are stuck in the same coverage hole. Then the AP will increase its power if this is possible.

The fact that WLC waits for several clients before raising the power avoids crazy behaviors of increasine/lowering/increasing/lowering.

The parameters for coverage hole events are configurable on the RRM part of WLC (number of clients, etc ...)

Nothing is configurable for pre-coverage hole as this is just "1 client only is reaching the coverage hole tresholds".

Hope this clarifies.

Nicolas

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Correct Answer
Nicolas Darchis Fri, 10/08/2010 - 05:36

Hello !

A pre-coverage hole is when a client stays for 5 seconds in a coverage hole. In other words, when a client is heard for some time at bad signal and it's not roaming, it must mean that this area is a coverage hole. This event is informational

A coverage hole event is when several clients are stuck in the same coverage hole. Then the AP will increase its power if this is possible.

The fact that WLC waits for several clients before raising the power avoids crazy behaviors of increasine/lowering/increasing/lowering.

The parameters for coverage hole events are configurable on the RRM part of WLC (number of clients, etc ...)

Nothing is configurable for pre-coverage hole as this is just "1 client only is reaching the coverage hole tresholds".

Hope this clarifies.

Nicolas

bbxie Sat, 10/09/2010 - 04:53

Thanks Nicolas! Already got reply from Cisco TAC Sydney. However not happy with the result which says that when coverage hole is seleced, unfortunately there is no workaround to stop pre coverage event being sent to notification receiver.

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