User guide

Security
7-23
Alvarion
bigger than the transition, this can still be considered to be a single key scheme,
because most of the time only a single key is in use.
Alternative Schemes
Alternative schemes can be envisaged, which have main life periods in which
two or more keys are active. An example is given in Table 7-6
Table 7-6 :Alternative Schemes
Table 7-6 gives a scheme where at each period two keys are in use; at the end
of each period, the oldest key is no longer valid and needs to be replaced at all
stations. Advantage of this scheme versus the scheme in Table 7-5 is that it
requires less frequent configuration changes at all Base Stations.
Period AP Configuration Out-
ward
STA
Configuration(s)
In-ward
# Description Keys 1-2-3-4 Tx Key Keys 1-2-3-4 Tx Key
0 Main life key A A-0-0-0 1 A A-B-C-D 1 A
1 Main life A+B A-B-0-0 2 B = 1|2 A | B
2 Main life B+C 0-B-C-0 3 C = 2|3 B | C
3 Main life C+D 0-0-C-D 4 D = 3|4 C | D
4 Main life D+E E-0-0-D 1 E A-B-C-D
E-F-G-H
4
1
D
E
5 Main life E+F E-F-0-0 2 F E-F-G-H 1|2 E | F