RE: [STDS-802-21] Heavily revised call flow example
Folks,
Please review and let Charlie know if you have any comments.
We need to make the draft ready for WG ballot.
Regards,
_Subir
-----Original Message-----
From: Charles E. Perkins [mailto:charles.perkins@xxxxxxxxxxxxx]
Sent: Thursday, August 23, 2012 6:37 PM
To: STDS-802-21@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-21] Heavily revised call flow example
Hello folks,
Here is a replacement for the first signaling diagram in existing Annex N. Please review it for understandability and accuracy. I have changed a lot of things. Foremost, I clarified the algorithm for distributing MNmsrk. What the diagram shows is that MNmsrk is computed from MNmirk.
More specifically:
T_pos extracts MNmirk in message received from S_pos.
T_pos computes MNmsrk from MNmirk
T_pos distributes MNmsrk to T_poa
T_pos returns MNnetworkaccessID to S_pos
S_pos sends MNnetworkaccessID and MNmirk to MN
MN computes MNmsrk from MNmirk using same well-known
algorithm used by T_pos.
I know this is a possible way to make the preauthentication.
I reckon it is compatible with the intention of the rest of the document in the way that functionality and naming are designed for S_pos, T_pos, T_pos, etc. -- but I'd really appreciate separate verification of that.
I also redrew the signaling diagram to better display what I think was intended, and supplying parameters according to the above algorithm for distributing MNmsrk etc.
I hope the example is:
- accurate
- clear
- consistent with previous 802.21(c) design
The algorithm for computing MNmsrk from MNmirk *could* be media-specific. I can design a media-independent algorithm to be used in other cases when no media-specific algorithm has been mandated, but somehow it seems likely that a media-specific key such as MNmsrk would be computed by a media-specific algorithm. Notably, if it is required to compute MNmsrk without regard to the value of MNmirk, then the above method is incomplete or maybe even broken.
Your comments will be very much appreciated. If I have this correctly, I will try to complete the document revision tomorrow. Visio does work. I am not going to spend much time on the long Annex containing the use cases for handovers between WiFi and WiMAX, etc., at least not before getting this revision to a consistent state worthy of consideration by the 802.21 task group.
Regards,
Charlie P.