This value indicates the data rate for mc/bc packets from this
radio interface. sixMbps(6), nineMbps(9), twelveMbps(12), eighteenMbps(18),
twentyFourMbps(24), thirtySixMbps(36), fortyEightMbps(48), and fiftyFourMbps(54)
are for 11a and g-only mode. The default for b-only and b+g mode is
oneMbps(1), twoMbps(2), fiveAndHalfMbps(5) and elevenMbps(11).