Sequence numbers jumping - question - follow up

Joshua Wright Joshua.Wright at
Tue Oct 29 09:23:14 EST 2002

Jouni's suggestion that the firmware of my card (which is a SMC 2632W, fw 1.02 - sorry for forgetting to mention earlier) is skipping sequence numbers when changing the channel appears to be correct.

I ran another test with FakeAP using a single channel instead of hopping through 11 channels and sequence numbers remained consistent, always incrementing by 1.

Thanks for the assistance.

-Joshua Wright
Team Leader, Networks and Systems
Johnson & Wales University
Joshua.Wright at

fingerprint: FDA5 12FC F391 3740 E0AE BDB6 8FE2 FC0A D44B 4A73

> -----Original Message-----
> From: Jouni Malinen [mailto:jkmaline at]
> Sent: Monday, October 28, 2002 6:28 PM
> To: hostap at
> Subject: Re: Sequence numbers jumping - question
> On Mon, Oct 28, 2002 at 04:43:33PM -0500, Joshua Wright wrote:
> > Is their any reasons the HostAP drivers would skip some of 
> the sequence number values when changing the frequency or 
> ESSID?  It could be my data capture implementation or the 
> Cisco internal channel hopping mechanism that is preventing 
> me from seeing all the frames, but I don't have a way to confirm this.
> I would assume that the "missing" sequence numbers were used on some
> other frames that were not seen in the capture.
> > Can anyone shed some light on how sequence numbers are 
> handled in HostAP?  I didn't see an obvious reference to it 
> in the code - if someone can point me to the right general 
> area instead, that would be good too. :)
> They aren't, so no wonder you didn't find any obvious references to
> them.. Firmware takes care of assigning seq# for the outgoing 
> frames. I
> don't think anything breaks by skipping some sequence numbers, so it
> might also be that the firmware happens to skip them when 
> configuration
> (like channel or ssid) is changed.
> -- 
> Jouni Malinen                                            PGP 
> id EFC895FA
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