Is RF band field in the WPS of Beacon necessary only when AP is concurrent dual-band AP?

Jouni Malinen j
Mon Dec 17 06:12:24 PST 2012

On Mon, Dec 17, 2012 at 10:26:20AM +0800, Stone wrote:
> In wps_set_ie(), we checked dual-band when build rf band info for beacon,
> if (wps_build_version(beacon) ||
> ......
>    (reg->dualband && wps_build_rf_bands(&reg->wps->dev, beacon)) ||
>  ......)
> while for probe resp, we did not check the dualband flag,
> if (wps_build_version(probe) ||
> ......
>    wps_build_rf_bands(&reg->wps->dev, probe) ||
> ......

That Beacon version is a bit newer design and apparently the Probe
Response one did not get updated to make this more consistent.

> The reg->dualband flag will be set when the AP is a concurrent dual
> band AP in hostapd_init_wps(). So does it mean RF band is necessary
> when AP is concurrent dual-band AP? In WSC spec, we can only get that
> rf band info indicates all RF bands available on the AP and a
> dual-band(not concurrent dual-band) AP must provide this attribute.

The RF Bands information is used only for PBC session overlap detection
and it is not really needed for any other case than concurrent dualband
AP. I changed the implementation to be more consistent for Beacon and
Probe Response frames (i.e., both use the reg->dualband condition).

Jouni Malinen                                            PGP id EFC895FA

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