3Com 10014303 - Manual (Page 18)

2.2 The Basic Message Interaction Flow of TACACS+
For example, use TACACS+ to implement AAA on a telnet user, and the basic
message interaction flow described below is used:
1) A user requests access to the router. The router(TACACS+ client) sends the
authentication start packet to the TACACS+ server upon receipt of the request.
2) The TACACS+ server sends an authentication response packet requesting the
user name. The router (TACACS+ client) asks the user for the user name upon
receipt of the response packet.
3) After receiving the user name from the user, the router (TACACS+ client) sends
the authentication packet to the TACACS+ carrying the user name.
4) The TACACS+ server sends back an authentication response packet, requesting
the login password. Upon receipt of the response packet, the router (TACACS+
client) requests the user for the login password.
5) The router (TACACS+ client) sends an authentication packet carrying the login
password to the TACACS+ server.
6) The TACACS+ server sends back the authentication response packet indicating
that the user has passed the authentication.
7) The router (TACACS+ client) sends the user authorization packet to the
TACACS+ server.
8) The TACACS+ server sends back the authorization response packet, indicating
that the user has passed the authorization.
9) Upon receipt of the response packet indicating an authorization success, the
router (TACACS+ client) pushes the configuration interface of the router to the
user.
10) The router (TACACS+ client) sends the accounting start request packet to the
TACACS+ server
11) The TACACS+ server sends back an accounting response packet, indicating that
it has received the accounting start request packet.
12) The user quits, and the router (TACACS+ client) sends the accounting stop
packet to the TACACS+ server.
13) The TACACS+ server sends back the accounting stop packet, indicating that the
accounting stop request packet has been received.
The following figure illustrates the basic message interaction flow:
3Com Router Configuration Guide Addendum for V1.20
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