H3C S5100-SI Series Operation Manual page 332

Operation Manual – AAA
H3C S5100-SI/EI Series Ethernet Switches
Figure 1-6 AAA implementation procedure for a telnet user
The basic message exchange procedure is as follows:
1) A user sends a login request to the switch acting as a TACACS client, which then
sends an authentication start request to the TACACS server.
2) The TACACS server returns an authentication response, asking for the username.
Upon receiving the response, the TACACS client requests the user for the
username.
3) After receiving the username from the user, the TACACS client sends an
authentication continuance message carrying the username.
4) The TACACS server returns an authentication response, asking for the password.
Upon receiving the response, the TACACS client requests the user for the login
password.
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Chapter 1 AAA Overview