Subject: [Capwap] Issue 61: Change WLAN->BSSID Mapping

From: "Pat Calhoun (pacalhou)" <[email-masked]>
Date: Mon, 1 May 2006 22:55:44 -0700

This is the fix to allow the WTP to tell the AC what BSSID it is using
for a given WLAN. Let me know if you are OK with this text before I sent
it to the list - with the understanding that we have very little time
left :(

11.4.  BSSID to WLAN ID Mapping

   The CAPWAP protocol allows the WTP to assign BSSIDs upon creation of
   a WLAN (see Section Section 11.8.1.1).  While manufacturers are free
   to assign BSSIDs using any arbitrary mechanism, it is advised that
   where possible the BSSIDs are assigned as a contiguous block.

   When assigned as a block, implementations can still assign any of the
   available BSSIDs to any WLAN.  One possible method is for the WTP to
   assign the address using the following algorithm: base BSSID address
   + WLAN ID.

   For instance, if a WTP had a base BSSID address of 00:01:02:00:00:00,
   and the AC sent an Add WLAN message with a WLAN Identifier of 2 (see
   Section Section 11.8.1.1), the BSSID for the specific WLAN on the WTP
   would be 00:01:02:00:00:02.

   The WTP communicates the maximum number of BSSIDs that it supports
   during the Config Request within the IEEE 802.11 WTP WLAN Radio
   Configuration message element (see Section 11.9.1).

[...]

 11.8.2.  IEEE 802.11 WLAN Config Response

[...]

11.8.2.1.  IEEE 802.11 Assigned WTP BSSID

   The IEEE 802.11 Assigned WTP BSSID is only included by the WTP when
   the IEEE 802.11 WLAN Config Request included the IEEE 802.11 Add WLAN
   message element.  The value field of this message element contains
   the BSSID that has been assigned by the WTP, which allows the WTP to
   perform its own BSSID assignment.

   The WTP is free to assign the BSSIDs the way it sees fit, but it is
   highly recommended that the WTP assign the BSSID using the following
   algorithm: BSSID = {base BSSID} + WLAN ID.

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                             BSSID                             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |             BSSID             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type:  TBD for IEEE 802.11 Assigned WTP BSSID

   Length:  6

   BSSID:  The BSSID assigned by the WTP for the WLAN created as a
      result of receiving an IEEE 802.11 Add WLAN.

Pat Calhoun
CTO, Wireless Networking Business Unit
Cisco Systems
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From: "Pat Calhoun (pacalhou)" <[email-masked]>
Date: Mon, 1 May 2006 23:08:37 -0700

Oops - I cut and paste from an e-mail to the other co-authors. Ignore my
comment on sending to the list as I obviously already did :(

Pat Calhoun

> -----Original Message-----
> From: Pat Calhoun (pacalhou) 
> Sent: Monday, May 01, 2006 10:56 PM
> To: capwap
> Subject: [Capwap] Issue 61: Change WLAN->BSSID Mapping 
> 
> This is the fix to allow the WTP to tell the AC what BSSID it 
> is using for a given WLAN. Let me know if you are OK with 
> this text before I sent it to the list - with the 
> understanding that we have very little time left :(
>