VDSL 頻頻斷線

Hi all,

小弟家裡是裝 中華電信的VDSL
近日時常突然斷線一兩分鐘後又會自動恢復

網路配置： 中華電信數據機 接上 ASUS RT-AC51U 分享給其他設備用(PC, 手機, NAS等)
當問題發生時，PC是會看到網路連線的地方出現"驚嘆號"表示連現異常
但是我看數據機的紅燈確沒有亮

我查閱了 AC51U 的log，看起來又像是網路端的問題
log:
Jan 27 19:58:10 WAN Connection: Fail to connect with some issues.
Jan 27 19:58:10 stop_nat_rules: apply the redirect_rules!
Jan 27 19:59:01 WAN Connection: WAN was restored.
Jan 27 19:59:01 start_nat_rules: apply the nat_rules(/tmp/nat_rules_ppp0_vlan2)!
Jan 27 20:05:54 kernel: rt2860v2:ASSOC - Assign AID=4 to STA 9c:44:3d:3a:00:4c
Jan 27 20:43:59 WAN Connection: Fail to connect with some issues.
Jan 27 20:43:59 stop_nat_rules: apply the redirect_rules!
Jan 27 20:44:54 WAN Connection: WAN was restored.
Jan 27 20:44:54 start_nat_rules: apply the nat_rules(/tmp/nat_rules_ppp0_vlan2)!
Jan 27 20:48:10 kernel: rt2860v2:ASSOC - Assign AID=6 to STA 24:0a:64:49:0f:db
Jan 27 20:53:03 WAN Connection: Fail to connect with some issues.
Jan 27 20:53:03 stop_nat_rules: apply the redirect_rules!
Jan 27 20:53:55 WAN Connection: WAN was restored.
Jan 27 20:53:55 start_nat_rules: apply the nat_rules(/tmp/nat_rules_ppp0_vlan2)!
Jan 27 20:58:03 WAN Connection: Fail to connect with some issues.
Jan 27 20:58:03 stop_nat_rules: apply the redirect_rules!
Jan 27 20:58:54 WAN Connection: WAN was restored.
Jan 27 20:58:54 start_nat_rules: apply the nat_rules(/tmp/nat_rules_ppp0_vlan2)!
Jan 27 21:18:11 WAN Connection: Fail to connect with some issues.
Jan 27 21:18:11 stop_nat_rules: apply the redirect_rules!
Jan 27 21:19:04 WAN Connection: WAN was restored.
Jan 27 21:19:04 start_nat_rules: apply the nat_rules(/tmp/nat_rules_ppp0_vlan2)!

能否有大大能給小弟一些指教

謝謝