tx question

Jouni Malinen jkmaline at cc.hut.fi
Wed May 14 21:55:09 EDT 2003

On Wed, May 14, 2003 at 02:48:51PM -0500, Raymond Hall wrote:

> what does the last line in iwconfig exactly mean, e.g:
> Tx excessive retries:330143  Invalid misc:69271 
> What's a retry in a wireless medium, what are invalid misc?

IEEE 802.11 requires acknowledgement of unicast frames. If a frame is
not acknowledged, it will be retransmitted (up to some maximum number of
times). Excessive retries counter shows the number of frames that were
not acknowledged at all.

Invalid misc reports various miscellaneous errors in frames. In the case
of Host AP driver, that number includes FCS (frame control checksum)
errors in received frames, frames (RX) that were discarded because of
insufficient buffer space (in wlan card RAM) and transmit attempts for
frames with invalid source address.

You can see more detailed counters in /proc/net/hostap/wlan#/stats. The
numbers shown in iwconfig output are based on these counters.

Jouni Malinen                                            PGP id EFC895FA

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