IBSS = no response ????

Ly Hong Ly
Tue May 16 00:30:09 PDT 2006

Hi Dan

I don't know if you have already read my mail in the mailing list, so I
repeat it again. 
I have read several articles, as well the standard 802.11i and I come to
solution that the older WLAN-card-hardware does not support IBSS mode
with more than 2 nodes.

The reason I guess is the limitation of storing the keys in harware,
since most standard IEEE 802.11 hardware designs only allow up to 4
different keys installed in the memory. Suppose TKIP is set:

As I have understood, for each ad hoc link a different WPA transient key
(a set of 4 keys) is needed for pairwise communications over each link.
Hence there may be up to N * (N - 1) / 2 separate transient keys for
pairwise communication within a network of N nodes.
In this case:
N=2, number of keys to be stored in the
wlan-card-hardware=N*(N-1)/2*4=2*(2-1)/2*4=4. Since no more storing
memory is left, it works only with 2 nodes. 

Other solution is not standard compliant !

Van Hong - Ly

IABG - Germany


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