Relevance of GTK key index?

Jouni Malinen j
Mon Aug 15 21:38:17 PDT 2011

On Fri, Aug 12, 2011 at 01:03:19PM -0500, Harshal Chhaya wrote:
> I am seeing that my clients have problems if the GTK is at index 2 but
> connect just fine if the GTK is at index 1. The connection manager on
> these clients (custom code), restarts the connection process if the
> GTK is at index 2 because it seems that the radio firmware expects the
> GTK at index 1. After a few such tries, the connection succeeds
> because hostapd somehow switches the GTK index to 1 and my connection
> manager is happy.

Which client card/driver/supplicant is this? It's horribly broken if it
is unable to use key index 2 for the GTK.

> I am trying to understand what causes hostapd to use a different index
> and if I can influence it to use index 1 to start with? This will
> avoid all the retries and improve the connection time.

Fixing the client would be the solution here.. Two key indexes are used
to allow the GTKs to be switched in a coordinated way with multiple
stations in the network.

Jouni Malinen                                            PGP id EFC895FA

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