302 Configuring APs
NN47250-500 (Version 03.01)

Configuring AP-WSS security

WSS Software provides security for management traffic between WSSs and Distributed APs. When the feature is
enabled, all management traffic between Distributed APs that support encryption and the WSS is encrypted. AP-WSS
security is set to optional by default.
The encryption uses RSA as the public key cryptosystem, with AES-CCM for data encryption and integrity checking
and HMAC-MD5 for keyed hashing and message authentication during the key exchange. Bulk data protection is
provided by AES in CCM mode (AES CTR for encryption and AES-CBC-MAC for data integrity). A 64-bit Message
Authentication Code is used for data integrity.

Encryption key fingerprint

APs are configured with an encryption key pair at the factory. The fingerprint for the public key is displayed on a label
on the back of the AP, in the following format:
RSA
aaaa:aaaa:aaaa:aaaa:
aaaa:aaaa:aaaa:aaaa
If the AP is already installed, you can display the fingerprint in WSS Software. (See “Finding the fingerprint” on
page 303.)

Encryption options

By default, a WSS can configure and manage a Distributed AP regardless of whether the AP has an encryption key, and
regardless of whether you have confirmed the fingerprint by setting it in WSS Software.
You can configure a WSS to require Distributed APs to have an encryption key. In this case, the switch also requires
their fingerprints to be confirmed in WSS Software. When AP security is required, an AP can establish a management
session with the WSS only if its fingerprint has been confirmed by you in WSS Software.
If you do not want any APs to use encryption for management information, you can disable the feature.
Table 14 lists the AP security options and whether an AP can establish a management session with a WSS based on the
option settings.
Note. This feature applies to Distributed APs only, not to directly connected APs
configured on AP access ports.
Note. The maximum transmission unit (MTU) for encrypted AP management traffic is
1498 bytes, whereas the MTU for unencrypted management traffic is 1474 bytes. Make
sure the devices in the intermediate network between the WSS and Distributed AP can
support the higher MTU.