How does Ad-Hoc detection work?

Aruba Employee

Product and Software: This article applies to all Aruba controllers and ArubaOS versions.

 

What is 802.11 Ad-Hoc network?

 

802.11 has 2 operation mode: "Infrastructure" mode and "Independent" mode. Most of the wireless installation including Aruba networks use Infrastructure mode. With this mode, all wireless clients communicate to APs in order to access the distribution system (the networks and Internet). There's no direct communication between clients. All traffic will be handled by the AP.

With Ad-Hoc (Independent, IBSS) mode, wireless clients will directly communicate with each other in a peer to peer manner.

 

How an Ad-Hoc network operates?

 

The Ad-Hoc network works almost the same way as the Infrastructure networks. However, since there's no AP, the first Ad-Hoc station will start sending beacons once it's up. it will randomly pick a BSSID. The other stations that joins this network will agree upon on this BSSID and start sending beacon periodically with the same BSSID.

 

Pros and Cons of the Ad-Hoc networks:

 

Pros:

1 fast deployment for emergency or temporary group

2 cost saving

Cons:

1 Most likely not secure. This is the main driver to detect Ad-Hoc network and disable it.

2 difficult to manage

 

How does Ad-Hoc detection work?

 

A frame can be detected to be part of an Adhoc network by checking if neither the FromDS nor the toDS bit of the 802.11 header is set.

The FromDS or the toDS is part of the 802.11 frame control field.

 

Please check the image below for the details:

 

adhoc.JPG

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Last update:
‎07-02-2014 02:04 PM
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