"without using web interface, there is another method to do that?"
Maybe only script command can do that without web utility. It is quite difficult to create a script command. When using telnet, you can check if there are some available commands by checking Help information.

on all various command that i say in help there is not an option to disconnect wan but only to create,view and delete connection.
there is another method to do?i have a raspberry with raspbian and i think to use an http recorder to do that instead of telnet.
but for one reason or another i not found anythink that work.
the only software that work is pureload but is not automatically to launch...

SOLUTION CREATED BY MYSELF:

I found a workaroud to do that with telnet, is not perfect but it work!
In telnet access you can only change the configuration of the wan interface, so i made a script to enter with telnet, change user and password with fake data (that forcing to disconnect) and re-enter correct data in wan interface.
i have tried different solution but the best for my case is a script that request telnet and expect (sudo apt-get install telnet except)

--------------------------
#!/bin/bash

expect << EOF
spawn telnet 192.168.1.1
expect "username:"
sleep 1
send "admin\r"
expect "password:"
sleep 1
send "admin\r"
sleep 2
expect "*#"
send "wan set service pppoe_8_35_0_d --protocol pppoe --username fakedata --password fakedata\r"
sleep 6
send "\r"
sleep 1
expect "*#"
send "wan set service pppoe_8_35_0_d --protocol pppoe --username ispusername --password isppassword\r"
sleep 6
send "\r"
sleep 1
expect "*#"
send "logout"

exit

EOF

----------------------------

and now i have write a Visual Basic Script for doing the same thing in Windows!
------------------------
set WshShell = WScript.CreateObject("WScript.Shell")
WshShell.Run "cmd"
WScript.Sleep 100
WshShell.AppActivate "C:\Windows\system32\cmd.exe"
WScript.Sleep 1000
WshShell.SendKeys "telnet 192.168.1.1~"
WScript.Sleep 1000
WshShell.SendKeys "admin~"
WScript.Sleep 1000
WshShell.SendKeys "admin~"
WScript.Sleep 2000
WshShell.SendKeys "wan set service pppoe_8_35_0_d --protocol pppoe --username fakedata --password fakedata~"
WScript.Sleep 6000
WshShell.SendKeys "~"
WScript.Sleep 1000
WshShell.SendKeys "wan set service pppoe_8_35_0_d --protocol pppoe --username ispusername --password isppassword~"
WScript.Sleep 6000
WshShell.SendKeys "~"
WScript.Sleep 1000
WshShell.SendKeys "logout~"
WScript.Sleep 100
Set objWMI = GetObject("winmgmts:{impersonationLevel=impersonate}")
Set objProcess = objWMI.InstancesOf("Win32_process")
For each Process in objProcess
If (instr(1,lcase(Process.name),lcase("telnet.exe")) > 0) then
Process.terminate 0
End If
Next
WshShell.SendKeys "exit~"
----------------

You do a great job!!;)

;) Hi, 'another more quickly could also be to change the connection mode from automatic to manual and then bring it back to automatic.
so:

wan set service pppoe_8_35_0_d --protocol pppoe --conntrigger manual
or
wan set service pppoa_8_35_0_d --protocol pppoa --conntrigger manual

wan set service pppoe_8_35_0_d --protocol pppoe --conntrigger always
or
wan set service pppoa_8_35_0_d --protocol pppoa --conntrigger always

I tried it and it works.

Hi, here is the script tested and working with some changes and checks.
Greetings.


#!/bin/bash

clear
current_ip=$(wget -qO- http://ipecho.net/plain)
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "Internet Current IP: "$current_ip
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
sleep 3

while true; do

clear
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "Start Procedure Disconnecting...."
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"

expect << EOF
sleep 3
spawn telnet 192.168.1.254
expect "username:"
sleep 1
send "admin\r"
expect "password:"
sleep 1
send "password"
sleep 1
send "\r"
sleep 2
expect "*#"
send "\r"
sleep 1
send "\r"
send "wan set service pppoa_8_35_1_d --protocol pppoa --conntrigger manual"
sleep 1
send "\r"
sleep 5
send "\r"
sleep 3
expect "*#"
sleep 1
send "logout"
sleep 1
send "\r"
sleep 3


exit


EOF
clear
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "Disconnecting Happened Successfully."
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
sleep 5
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "Start Procedure Reconnecting...."
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
sleep 2
expect << EOF
sleep 3
spawn telnet 192.168.1.254
expect "username:"
sleep 1
send "admin\r"
expect "password:"
sleep 1
send "password"
sleep 1
send "\r"
sleep 2
expect "*#"
send "\r"
sleep 1
send "\r"
send "wan set service pppoa_8_35_1_d --protocol pppoa --conntrigger always"
sleep 1
send "\r"
sleep 5
send "\r"
sleep 2
send "\r"
expect "*#"
sleep 3
send "logout"
sleep 2
send "\r"
sleep 2


exit


EOF


new_ip=$(wget -qO- http://ipecho.net/plain)
echo " "
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "Reconnecting Happened Successfully."
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "Old IP: "$current_ip
echo "New IP: "$new_ip
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
sleep 3

if [[ $current_ip != $new_ip ]];
then
sleep 1
clear
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "Procedure Change IP perfectly Successful."
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "Old IP: "$current_ip
echo "-----------------------------------------------------"
echo "New IP: "$new_ip
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
sleep 3
break;
fi
sleep 2
clear
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "The procedure IP change failed"
echo "New Attempt to Change IP, in progress..."
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "Old IP: "$current_ip
echo "-----------------------------------------------------"
echo "New IP: "$new_ip
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "-----------------------------------------------------"
echo "Wait..... Please..."
echo "-----------------------------------------------------"
sleep 5


done

Wow! Kudos to your threads!