Capwap Mailing List: Issue 194: Format of Destination WLAN unclear

[Pat Calhoun (pacalhou) (pcalhoun]

All,

The Destination WLAN in section 4 of the IEEE 802.11 binding spec
defines the use of the field, which is used when broadcast and/or
multicast packets are sent from the AC to the WTP. I just noticed that
while the text talks about setting bits 1, it doesn't actually
explicitely state which one is bit 1. I am therefore recommending a
change to the text to ensure that all implementations interpret this
important field properly:

<proposed text>
4.  CAPWAP Data Message Bindings
[...]
      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |        WLAN ID bitmap         |            Reserved           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      WLAN ID bitmap:   This bit field indicates the WLAN ID (see
         Section 6.1) on which the WTP will transmit the included frame.
         For instance, if a multicast packet is to be transmitted on
         WLANs 1 and 3, the bits for WLAN 1 and 3 of this field would be
         enabled.  WLAN 1 is represented by bit 15 in the figure above,
         or the least significant bit, while WLAN 16 would be
         represented by bit zero (0), or the most significant bit, in
         the figure.  This field is to be set to all zeroes for unicast
         packets and is unused if the WTP is not providing IEEE 802.11
         encryption.
</proposed text>

PatC