Re: protocol mods

From: Jouni Malinen (
Date: 2001-12-18 18:10:38 UTC

On Tue, Dec 18, 2001 at 12:50:01AM +0000, Jerritt Collord wrote:

> Has anyone investigated the possibility or desireability of modifying this
> driver such that essentially 802.11b ACK frames are removed, e.g. the
> (data) recipient doesn't send one, and the would-be receiver doesn't
> expect one?

Like Pedro already said, this cannot be done very easily. Retry limit could probably be set to zero to remove low-level resend, but ACKs would be generated anyway. ACKs have tight timing restrictions and they need to be done on very low level (i.e., in the card firmware).

However, if you do not need 802.11 management functions, you could test so called pseudo ad-hoc mode. I haven't tested it very much with Prism2 cards, but at least Lucent's pseudo ad-hoc mode did not seem to use any management or control frames. This might be useful, e.g., in dedicated links between two stations.

Another performance improvement could be achieved by tuning various low-level interval times, but some values cannot be set without modifying firmware. 802.11b short preamble could be configured from the driver (HFA384X_RID_CNFSHORTPREAMBLE), but it might not work on all cards. I haven't tested this much, but it might be useful if you have an environment in which there are no stations requiring default (long) preamble.

Jouni Malinen                                            PGP id EFC895FA

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