QUOTE(blacktubi @ Mar 6 2017, 10:25 PM)
Your ADSL is stable but internet connection is dropped? How frequent is it?
Check your PPPOE configurations, make sure it is configured to be always on.
Was looking my logs, disconnected twice in the morning

.
Looked something like this.
DSL link down? Hmm..
2017-03-07 09:36:00 kernel: Link State: PVC_0 PPPoE down.
2017-03-07 09:36:00 kernel: Link State: DSL link down.
2017-03-07 09:36:02 WAN Connection: Fail to connect with some issues.
2017-03-07 09:36:03 stop_nat_rules: apply the redirect_rules!
2017-03-07 09:36:08 WAN Connection: Wan link down.
2017-03-07 09:36:13 kernel: Detect DSL status:0x08 into polling mode!!
2017-03-07 09:36:30 kernel: Detect DSL status:0x20 into INT mode!!
2017-03-07 09:36:30 kernel: Link State: DSL link up.
2017-03-07 09:36:33 WAN Connection: Wan link up.
2017-03-07 09:36:39 syslog: Terminating on signal 15
2017-03-07 09:36:39 syslog: Connect time 110.4 minutes.
2017-03-07 09:36:39 syslog: Sent 1562404 bytes, received 14830085 bytes.
2017-03-07 09:36:39 syslog: LCP down.
2017-03-07 09:36:39 syslog: Connection terminated.
2017-03-07 09:36:39 syslog: LCP down.
2017-03-07 09:36:39 RFC1483/2684 bridge: Interface "nas0" created sucessfully
2017-03-07 09:36:39 RFC1483/2684 bridge: Communicating over ATM 0.0.35, encapsulation: LLC
2017-03-07 09:36:39 RFC1483/2684 bridge: Interface configured
2017-03-07 09:36:39 RFC1483/2684 bridge: RFC 1483/2684 bridge daemon started
2017-03-07 09:36:45 WAN Connection: Fail to connect with some issues.
2017-03-07 09:36:53 syslog: PPP session is 15815
2017-03-07 09:36:53 syslog: Connected to 10:1b:54:83:5d:57 via interface nas0
2017-03-07 09:36:53 syslog: Using interface ppp0
2017-03-07 09:36:53 syslog: Connect: ppp0 <--> nas0
2017-03-07 09:36:56 syslog: Remote message: Authentication success,Welcome!
2017-03-07 09:36:56 syslog: PAP authentication succeeded
2017-03-07 09:36:56 syslog: peer from calling number 10:1B:54:83:5D:57 authorized
2017-03-07 09:36:56 syslog: local IP address 60.48.46.187
2017-03-07 09:36:56 syslog: remote IP address 60.48.46.190
2017-03-07 09:36:56 syslog: primary DNS address 202.188.18.188
2017-03-07 09:36:56 syslog: secondary DNS address 1.9.1.9