The cipher protecting broadcast and multicast traffic: three octets of organisation identifier, then one selecting the suite.
One cipher, not a list, because every station in the BSS must decrypt the same group traffic. That makes it the floor — a BSS whose group cipher is TKIP is a TKIP network no matter what the pairwise list says.
| Value | Meaning |
|---|---|
| 2 | TKIP |
| 4 | CCMP-128 |
| 8 | GCMP-128 |
| 9 | GCMP-256 |
Bit values written b0 first, matching transmission order.
RSN > Group Data Cipher Suite