Cisco Wireless LAN Controller Configuration Guide, Release 7.5
Configuring a WLAN for Both Static and Dynamic WEP
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Configuring a WLAN for Both Static and Dynamic WEP

Configuring a WLAN for Both Static and Dynamic WEP

Restrictions for Configuring Static and Dynamic WEP

  • The OEAP 600 series does not support fast roaming for clients. Dual mode voice clients will experience reduced call quality when they roam between the two spectrums on OEAP602 access point. We recommend that you configure voice devices to only connect on one band, either 2.4 GHz or 5.0 GHz.
  • The controller software supports CCX versions 1 through 5. CCX support is enabled automatically for every WLAN on the controller and cannot be disabled. The controller stores the CCX version of the client in its client database and uses it to limit client functionality. Clients must support CCXv4 or v5 in order to use CCKM. For more information about CCX, see the Configuring Cisco Client Extensions section.
  • In a unified architecture where multiple VLAN clients are supported for a WGB, you also need to configure encryption cipher suite and WEP keys globally, when the WEP encryption is enabled on the WGB. Otherwise, multicast traffic for wired VLAN clients fail.

Information About WLAN for Both Static and Dynamic WEP

You can configure up to four WLANs to support static WEP keys, and you can also configure dynamic WEP on any of these static-WEP WLANs. Follow these guidelines when configuring a WLAN for both static and dynamic WEP:

  • The static WEP key and the dynamic WEP key must be the same length.
  • When you configure both static and dynamic WEP as the Layer 2 security policy, no other security policies can be specified. That is, you cannot configure web authentication. However, when you configure either static or dynamic WEP as the Layer 2 security policy, you can configure web authentication.

WPA1 and WPA2

Wi-Fi Protected Access (WPA or WPA1) and WPA2 are standards-based security solutions from the Wi-Fi Alliance that provide data protection and access control for wireless LAN systems. WPA1 is compatible with the IEEE 802.11i standard but was implemented prior to the standard’s ratification; WPA2 is the Wi-Fi Alliance's implementation of the ratified IEEE 802.11i standard.

By default, WPA1 uses Temporal Key Integrity Protocol (TKIP) and message integrity check (MIC) for data protection while WPA2 uses the stronger Advanced Encryption Standard encryption algorithm using Counter Mode with Cipher Block Chaining Message Authentication Code Protocol (AES-CCMP). Both WPA1 and WPA2 use 802.1X for authenticated key management by default. However, these options are also available:

  • 802.1X—The standard for wireless LAN security, as defined by IEEE, is called 802.1X for 802.11, or simply 802.1X. An access point that supports 802.1X acts as the interface between a wireless client and an authentication server, such as a RADIUS server, to which the access point communicates over the wired network. If 802.1X is selected, only 802.1X clients are supported.
  • PSK—When you choose PSK (also known as WPA preshared key or WPA passphrase), you need to configure a preshared key (or a passphrase). This key is used as the pairwise master key (PMK) between the clients and the authentication server.
  • CCKM—Cisco Centralized Key Management (CCKM) uses a fast rekeying technique that enables clients to roam from one access point to another without going through the controller, typically in under 150 milliseconds (ms). CCKM reduces the time required by the client to mutually authenticate with the new access point and derive a new session key during reassociation. CCKM fast secure roaming ensures that there is no perceptible delay in time-sensitive applications such as wireless Voice over IP (VoIP), enterprise resource planning (ERP), or Citrix-based solutions. CCKM is a CCXv4-compliant feature. If CCKM is selected, only CCKM clients are supported. When CCKM is enabled, the behavior of access points differs from the controller's for fast roaming in the following ways:
    • If an association request sent by a client has CCKM enabled in a Robust Secure Network Information Element (RSN IE) but CCKM IE is not encoded and only PMKID is encoded in RSN IE, then the controller does not do a full authentication. Instead, the controller validates the PMKID and does a four-way handshake.
    • If an association request sent by a client has CCKM enabled in RSN IE but CCKM IE is not encoded and only PMKID is encoded in RSN IE, then AP does a full authentication. The access point does not use PMKID sent with the association request when CCKM is enabled in RSN IE.
  • 802.1X+CCKM—During normal operation, 802.1X-enabled clients mutually authenticate with a new access point by performing a complete 802.1X authentication, including communication with the main RADIUS server. However, when you configure your WLAN for 802.1X and CCKM fast secure roaming, CCKM-enabled clients securely roam from one access point to another without the need to reauthenticate to the RADIUS server. 802.1X+CCKM is considered optional CCKM because both CCKM and non-CCKM clients are supported when this option is selected.

On a single WLAN, you can allow WPA1, WPA2, and 802.1X/PSK/CCKM/802.1X+CCKM clients to join. All of the access points on such a WLAN advertise WPA1, WPA2, and 802.1X/PSK/CCKM/
802.1X+CCKM information elements in their beacons and probe responses. When you enable WPA1 and/or WPA2, you can also enable one or two ciphers, or cryptographic algorithms, designed to protect data traffic. Specifically, you can enable AES and/or TKIP data encryption for WPA1 and/or WPA2. TKIP is the default value for WPA1, and AES is the default value for WPA2.

Configuring WPA1 +WPA2

Configuring WPA1+WPA2 (GUI)


    Step 1   Choose WLANs to open the WLANs page.
    Step 2   Click the ID number of the desired WLAN to open the WLANs > Edit page.
    Step 3   Choose the Security and Layer 2 tabs to open the WLANs > Edit (Security > Layer 2) page.
    Step 4   Choose WPA+WPA2 from the Layer 2 Security drop-down list.
    Step 5   Under WPA+WPA2 Parameters, select the WPA Policy check box to enable WPA1, select the WPA2 Policy check box to enable WPA2, or select both check boxes to enable both WPA1 and WPA2.
    Note   

    The default value is disabled for both WPA1 and WPA2. If you leave both WPA1 and WPA2 disabled, the access points advertise in their beacons and probe responses information elements only for the authentication key management method that you choose in Step 7.

    Step 6   Select the AES check box to enable AES data encryption or the TKIP check box to enable TKIP data encryption for WPA1, WPA2, or both. The default values are TKIP for WPA1 and AES for WPA2.
    Step 7   Choose one of the following key management methods from the Auth Key Mgmt drop-down list: 802.1X, CCKM, PSK, or 802.1X+CCKM.
    Note   

    Cisco OEAP 600 does not support CCKM. You must choose either 802.1X or PSK.

    Note   

    For Cisco OEAP 600, the TKIP and AES security encryption settings must be identical for WPA and WPA2.

    Step 8   If you chose PSK in Step 7, choose ASCII or HEX from the PSK Format drop-down list and then enter a preshared key in the blank text box. WPA preshared keys must contain 8 to 63 ASCII text characters or 64 hexadecimal characters.
    Note    The PSK parameter is a set-only parameter. The value set for the PSK key is not visible to the user for security reasons. For example, if you selected HEX as the key format when setting the PSK key, and later when you view the parameters of this WLAN, the value shown is the default value. The default is ASCII.
    Step 9   Click Apply to commit your changes.
    Step 10   Click Save Configuration to save your changes.

    Configuring WPA1+WPA2 (CLI)


      Step 1   Disable the WLAN by entering this command:

      config wlan disable wlan_id

      Step 2   Enable or disable WPA for the WLAN by entering this command:

      config wlan security wpa {enable | disable} wlan_id

      Step 3   Enable or disable WPA1 for the WLAN by entering this command:

      config wlan security wpa wpa1 {enable | disable} wlan_id

      Step 4   Enable or disable WPA2 for the WLAN by entering this command:

      config wlan security wpa wpa2 {enable | disable} wlan_id

      Step 5   Enable or disable AES or TKIP data encryption for WPA1 or WPA2 by entering one of these commands:
      • config wlan security wpa wpa1 ciphers {aes | tkip} {enable | disable} wlan_id
      • config wlan security wpa wpa2 ciphers {aes | tkip} {enable | disable} wlan_id

      The default values are TKIP for WPA1 and AES for WPA2.

      When you have VLAN configuration on WGB, you need to configure the encryption cipher mode and keys for a particular VLAN, for example, encryption vlan 80 mode ciphers tkip. Then, you need configure the encryption cipher mode globally on the multicast interface by entering the following command: encryption mode ciphers tkip.

      Step 6   Enable or disable 802.1X, PSK, or CCKM authenticated key management by entering this command:

      config wlan security wpa akm {802.1X | psk | cckm} {enable | disable} wlan_id

      The default value is 802.1X.

      Step 7   If you enabled PSK in Step 6, enter this command to specify a preshared key:

      config wlan security wpa akm psk set-key {ascii | hex} psk-key wlan_id

      WPA preshared keys must contain 8 to 63 ASCII text characters or 64 hexadecimal characters.

      Step 8   Enable or disable authentication key management suite for fast transition by entering this command:

      config wlan security wpa akm ft {802.1X | psk} {enable | disable} wlan_id

      Note    You can now choose between the PSK and the fast transition PSK as the AKM suite.
      Step 9   Enable or disable randomization of group temporal keys (GTK) between AP and clients by entering this command:

      config wlan security wpa gtk-random {enable | disable} wlan_id

      Step 10   If you enabled WPA2 with 802.1X authenticated key management or WPA1 or WPA2 with CCKM authenticated key management, the PMK cache lifetime timer is used to trigger reauthentication with the client when necessary. The timer is based on the timeout value received from the AAA server or the WLAN session timeout setting. To see the amount of time remaining before the timer expires, enter this command:

      show pmk-cache all

      If you enabled WPA2 with 802.1X authenticated key management, the controller supports both opportunistic PMKID caching and sticky (or non-opportunistic) PMKID caching. In sticky PMKID caching (SKC), the client stores multiple PMKIDs, a different PMKID for every AP it associates with. Opportunistic PMKID caching (OKC) stores only one PMKID per client. By default, the controller supports OKC.

      Step 11   Enable the WLAN by entering this command:

      config wlan enable wlan_id

      Step 12   Save your settings by entering this command:

      save config