[RP-PPPoE] How to send PADT after calling poff script

[徐凯]

Hi 
  I am using ubuntu to dial a pppserver on a wireless data card. The data card’s implementation requires PPPoE client to send PADT after PPP client send LCP TERMINATE-REQUEST.
  But from the wireshark’s log, after I run the poff script. Pppoe client doesn’t send the PADT.
  So how do I config so pppoe client can send PADT after I run the poff script?