3Com Switch 4800G 24-Port Configuration Manual page 755

Basic message exchange process of HWTACACS
The following takes Telnet user as an example to describe how HWTACACS
performs user authentication, authorization, and accounting. Figure 232 illustrates
the basic message exchange process of HWTACACS.
Figure 232 Basic message exchange process of HWTACACS for a Telnet user
1 A Telnet user applies to access the NAS.
2 Upon receiving the request, the HWTACACS client sends a start-authentication
packet to the HWTACACS server.
3 The HWTACACS server sends back an authentication response requesting the
username.
4 Upon receiving the request, the HWTACACS client asks the user for the username.
5 The user enters the username.
AAA/RADIUS/HWTACACS Overview 755