Compaq WL110 User Manual page 99

Single Key – No Transition
Table 7-1 shows a system, where at each point in time only one single key is
used. The key to be used is dictated by the AP settings, showing only one valid
key at each period. This requires a change over of keys at all stations more or
less synchronous with the Access Point configuration changes. This is not
practical and hence there are four keys.
Table 7-1 Single Key - No Transition
Period
# Description
0 Main life key A A-0-0-0
1 Main life key B 0-B-0-0
2 Main life key C 0-0-C-0
3 Main life key
D
4 Main life key E E-0-0-0
5 Main life key F 0-F-0-0
By initially configuring all stations with the keys for the first 4 periods, only the
Txkey index needs to be changed at all stations for the first three steps. At the
step from period 3 to period 4, the keys have to be changed at all STAs as well.
Single Key – Transition Period
To introduce a transition period between the main life of the successive keys, the
scheme has to be changed as shown in Tabl e7-2.
Table 7-2 Single Key - Transition Period
Period
# Description
0 Main life key A A-0-0-0
1 Transition A-B A-B-0-0
2 Main life key B 0-B-0-0
3 Transition B-C 0-B-C-0
4 Main life key C 0-0-C-0
5 Transition C-D 0-0-C-D
6 Main life key D 0-0-0-D
7 Transition D-E E-0-0-D
8 Main life key E E-0-0-0
9 Transition E-F E-F-0-0
AP Configuration Out-
ward
Keys 1-2-3- Tx Key
4
1 A
2 B
3 C
0-0-0-D 4 D
1 E
2 F
AP Configuration
Keys 1-2-3-4 Tx Key
1
2
2
3
3
4
4
1
1
2
STA Configuration(s) In-
Keys 1-2-3-4 Tx
A-B-C-D
=
=
=
E-F-G-H
=
Out- STA
ward Configuration(s)
Keys 1-2-3-4 Tx
A A-B-C-D
B =
B =
C =
C =
D =
D =
E A-B-C-D
E-F-G-H
E E-F-G-H
F =
ward
Key
1 A
2 B
3 C
4 D
1 E
2 F
In-ward
Key
1 A
1|2 A | B
2 B
2|3 B | C
3 C
3|4 C | D
4 D
4 D
1 E
1 E
1|2 E | F
Security 7-17