ZyXEL Communications NBG6503 User Manual page 220

EAP-TTLS (Tunneled Transport Layer Service)
EAP-TTLS is an extension of the EAP-TLS authentication that uses certificates for only the server-
side authentications to establish a secure connection. Client authentication is then done by sending
username and password through the secure connection, thus client identity is protected. For client
authentication, EAP-TTLS supports EAP methods and legacy authentication methods such as PAP,
CHAP, MS-CHAP and MS-CHAP v2.
PEAP (Protected EAP)
Like EAP-TTLS, server-side certificate authentication is used to establish a secure connection, then
use simple username and password methods through the secured connection to authenticate the
clients, thus hiding client identity. However, PEAP only supports EAP methods, such as EAP-MD5,
EAP-MSCHAPv2 and EAP-GTC (EAP-Generic Token Card), for client authentication. EAP-GTC is
implemented only by Cisco.
LEAP
LEAP (Lightweight Extensible Authentication Protocol) is a Cisco implementation of IEEE 802.1x.
Dynamic WEP Key Exchange
The AP maps a unique key that is generated with the RADIUS server. This key expires when the
wireless connection times out, disconnects or reauthentication times out. A new WEP key is
generated each time reauthentication is performed.
If this feature is enabled, it is not necessary to configure a default encryption key in the wireless
security configuration screen. You may still configure and store keys, but they will not be used while
dynamic WEP is enabled.
Note: EAP-MD5 cannot be used with Dynamic WEP Key Exchange
For added security, certificate-based authentications (EAP-TLS, EAP-TTLS and PEAP) use dynamic
keys for data encryption. They are often deployed in corporate environments, but for public
deployment, a simple user name and password pair is more practical. The following table is a
comparison of the features of authentication types.
Table 83 Comparison of EAP Authentication Types
Mutual Authentication
Certificate – Client
Certificate – Server
Dynamic Key Exchange
Credential Integrity
Deployment Difficulty
Client Identity Protection
Appendix D Wireless LANs
EAP-MD5 EAP-TLS
No Yes
No Yes
No Yes
No Yes
None Strong
Easy Hard
No No
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EAP-TTLS PEAP
Yes Yes
Optional Optional
Yes Yes
Yes Yes
Strong Strong
Moderate Moderate
Yes Yes
LEAP
Yes
No
No
Yes
Moderate
Moderate
No