Capwap Mailing List: Issue 193: Setting the RSC value in the EAPOL-Key frame

[Pat Calhoun (pacalhou) (pcalhoun]

All,

Yong identified the following issue during the WG Last Call:
   I have a question on the RSC value maintaince in AC. If the
implementation is 
   split MAC, and the WTP is providing the encryption/decryption
service.

   The IV/KeyID field will be removed before the 802.11 frame is passed
to AC.
   Where the AC can get the RSC info.? This value is needed in the
EAPOL-key 
   messages. I found no capwap control msg can pass this from WTP to AC.

   Is this an issue, or I missed something?

This was addressed in the spec, but only under the security
considerations
Section. It is clear that we need to make sure that it is addressed in
the
Core text as well. I am therefore proposing adding a simple paragraph in
Section 2.2.1:

<proposed text>
2.2.1.  Split MAC
[...]
   Note that during the EAPOL-Key exchange between the Station and the
   AC, the Receive Sequence Counter (RSC) field for the GTK needs to be
   included in the frame.  The value of zero (0) is used by the AC
   during this exchange.  Additional details are available in
   Section 9.1.
</proposed text>

PatC