eap Mailing List: why authenticator is not on the access node?

[Alper Yegin (alper.yegin]

Hi Sam,

 

Continuing the discussion we had during the EAP WG…..

 

Various mobile and wireless architectures place the authenticator (NAS) on a centralized node instead of on each access node (e.g., IEEE 802.11 access point (AP), IEEE 802.16 base station(BS)).

 

This is mostly driven by practical deployment considerations. Architectures like WiFi and WiMAX that need to support hundreds of AP/BS and seamless mobility across them tend to include a centralized element that manages the network access sessions of each mobile terminal. Various services such as mobility management (L2 and L3), network access, radio resources are controlled in that element.

 

Technically the NAS can be placed on the AP/BS, but given the high number of these elements, and the need to coordinate sessions as mobile stations move from one to other, a hierarchical model where all such management functionalities are aggregated in a centralized server is preferred.

 

I hope this clarifies the motivation behind the separation of NAS from the access nodes.

 

Regards,

 

Alper