10.4. Use of EAP in 802 Networks

We mentioned that for wireless links EAP is carried over link layer protocols such as PPP or EAPOL. IEEE 802 LANs provide their own inbuilt framing support for traffic the way PPP does for dial-up and cellular data links. The link characteristics are known in advance and network protocols and features are carried inside LAN 802 headers, so the LCP or NCP type functions of PPP are not needed either. For those reasons, authentication functionality was one of the most important features missing from 802 protocols when it came to controlling access over 802 links. This was the motivation behind the creation of 802.1X: to protect the network from unauthorized access by users trying to access Ethernet connections that were physically accessible to the public. Hence authentication and access control at the network point of presence became the main goal of 802.1X.

It should be noted that the recent popularity of 802.1X-based methods for providing security within 802.11 WLANs does not mean that 802.1X is only designed for 802.11. On the contrary, 802.1X is designed for all 802 type links. In fact, 802.1X design started before 802.11 specifications started with wired connections in mind, even though the latest version of 802.1X [8021X2004] was published yesterday (time of writing: 9:20 pm December 15, 2004) to facilitate the use of 802.1X with 802.11.

10.4.1. 802.1X Port-Based Authentication

The 802.1x model is a logical model consisting of a switched Ethernet ...

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