Subject: [Capwap] Issue 50: Increase maximum number of BSSs

From: "Pat Calhoun (pacalhou)" <[email-masked]>
Date: Mon, 1 May 2006 10:59:32 -0700

I would recommend that we reject this issue. 16 BSSIDs is a large
number, and the overhead in generating 16 or more beacons outweighs the
usefullness in advertising that many networks.

Pat Calhoun
CTO, Wireless Networking Business Unit
Cisco Systems
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From: Jim Murphy <[email-masked]>
Date: Mon, 01 May 2006 15:27:16 -0700

It seems that the limit of 16 BSSIDs is primarily motivated
by this WLAN/Status field in the data header. Perhaps the WLAN/Status
field should be a broadcast domain identifier (a .1q tag or VLANID).
WTPs should then be told of the VLANID to BSSID/broadcast-key mapping
via control plane messages and replicate packets accordingly.

If a VLANID is used in place of this bitmap, the protocol will scale
better. With the current proposal, I am concerned about WTPs that have
many radios or offer multiple VLANs per BSSID.

Thanks,

Jim

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From: "Dorothy Stanley" <[email-masked]>
Date: Tue, 2 May 2006 11:25:54 -0700

All,

Looking at the original Issue 50 text:

> Page 34, Section 5.1.3. LWAPP seems to assume that WLAN
> radios will support
> 16 BSS's per Radio. It would be better not assume that every
> WTP supports 16 radios and add a field to indicate the number
> of virtual networks per radio.
At one point, the sheer number of beacons will saturate the air waves,
so we need to pick a maximum. What number do we want?

I think the issue name does not match the comment.
It's not clear that the commenter is asking for more than 16 BSSIDs, but
rather notes that the full
16 are assumed to be supported at the WTP.  What if the WTP only supports 4?
There is no way currently
for the WTP to communicate this to the AP. Section 5.1.3 is the WTP Radio
information message element.
One solution would be to add a "Number of BSSIDs supported" field to that
message element.
Another solution would be to add a new IEEE 802.11 message element, to
indicate the number of
BSSIDs supported, and include that new message element in the appropriate
messages. I suggest the
later, to keep BSSIDs in the .11 binding definition. And,
separately, keep the max at 16 BSSIDs.

Dorothy