SMC Networks SMC2552W-G2-17 manual Radio Interface

Radio Interface 6

the cipher used for broadcast frames is always TKIP. WEP encryption is not allowed.

•Key Caching: WPA2 provides fast roaming for authenticated clients by retaining keys and other security information in a cache, so that if a client roams away from an access point and then returns, re-authentication is not required. When a WPA2 client is first authenticated, it receives a Pairwise Master Key (PMK) that is used to generate other keys for unicast data encryption. This key and other client information form a Security Association that the access point names and holds in a cache.

•Preauthentication: Each time a client roams to another access point it has to be fully re-authenticated. This authentication process is time consuming and can disrupt applications running over the network. WPA2 includes a mechanism, known as pre-authentication, that allows clients to roam to a new access point and be quickly associated. The first time a client is authenticated to a wireless network it has to be fully authenticated. When the client is about to roam to another access point in the network, the access point sends pre-authentication messages to the new access point that include the client’s security association information. Then when the client sends an association request to the new access point, the client is known to be already authenticated, so it proceeds directly to key exchange and association.

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