AP in Monitor Mode - TOMM and Probe Request Forwarding

[peter.krohn]

I am struggeling to find documentation regarding the behaviour of an AP in Monitor Mode as to it's rolde in contributing with Location data for the MSE, and about the more exact details about Probe Request Forwarding

- Will an AP in normal monitor mode send information to the Controller about probes it sees that includes probes for WLAN's served by AP's in the AP Group to which the monitor mode AP belongs?

- Does an AP in Monitor Mode with TOMM enabled still listen to probes for client location in the same way as above (I have only seen the advantages to TAG location in documentation)

Does anyone have input regarding changing Probe Request Forwarding on the AP's to include sending information about unacknowledged probes?

What rate-limiting interval should be set? What pr. client pr. radio number should be set?

If anyone has changed the Probe Request Forwarding - what was the incerase in number of clients tracked?

In the Wireless Controller Configuration Guide (rel 7.4) it is stated that:

The controller can use the information from unacknowledged probe requests to improve the location accuracy

Does anyone know if unacknowledged probes are forwarded to the MSE for location calculation?

[Dhiresh Yadav]

Hi ,

You have mixed few questions here.

Monitor mode AP do constant channel scanning hence should not do location stuff.

ELM APs .should do limited Wips plus Local which consist of Location also.

WSM module in 3600/3700 can act as dedicate Wips along with full location support.

It is clearly written that "unacknowledged probe requests to improve the location accuracy"..which means that they are used for this purpose. 

I dont think any Probe request (Acknowledged pr Unack.) is forwarded to the MSE  RSSI information from the Probes is fetched and send to the MSE by WLC.

Regards

Dhiresh

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[peter.krohn]

A Monitor Mode AP can be used to tracking optimization according to Cisco Wireless LAN controller Configuration Guide , Release 7.4:

To optimize the monitoring and location calculation of RFID tags, you can enable tracking optimization on up to four channels within the 2.4-GHz band of an 802.11b/g access point radio

Off course the AP it self does not 'do location stuff' but reports to the WLC that passes messages to the MSE - but it does deliver data relevant for location calculation.

To my understanding the information in the client probe requests is the basis of the information passed from the AP to the Controller (off course it is not the probe itself, but an extract of the data in the probe enriched with ex RSSI) and further to the MSE. 

It can however  from a location point of view be very interesting to register probes to unknown (ie not supported by the AP) SSID in some usecases - which is the reason that I need to know what the meaning of '...to improve location accuracy' is more exactly. How is this done - and are those sent to the MSE for location calculation of the client/MAC seen?

[Dhiresh Yadav]

Hi Peter,

Can you please open a TAC case if you want dedicated analysis and confirmed and tested behaviour ?

Because from my point of view , Whatever you just described is not creating any confusion ...So if you enable forwarding UnAck as well ..both Ack and Unack. would be used to fetch RSSI info and that would be sent to the MSE for location tracking by the WLC.... For RFID tags...looks like there is an optimization available for Monitor APs on specific channels...I was unaware of that.

Regards

Dhiresh