P874 & RT-N16 No response to 10 echo-requests

求解

小弟家的P874跟RT-N16一直怪怪的
使用RT-N16撥接固定IP
用一陣子會突然瞬斷
有時候七八天都不斷
有時候一天斷兩三次
登入RT-N16介面重撥都無法
一定要跑去P874面前
把電源拔掉再重接
RT-N16才有辦法順利重新撥號

以下是斷線時RT-N16擷取的訊息求幫解
Feb 14 10:57:08 pppd[457]: No response to 10 echo-requests
Feb 14 10:57:08 pppd[457]: Serial link appears to be disconnected.
Feb 14 10:57:08 pppd[457]: Connect time 209.5 minutes.
Feb 14 10:57:08 pppd[457]: Sent 78516204 bytes, received 2325916618 bytes.
Feb 14 10:57:08 dnsmasq[471]: read /etc/hosts - 3 addresses
Feb 14 10:57:08 dnsmasq[471]: using nameserver 8.8.8.8#53
Feb 14 10:57:08 dnsmasq[471]: using nameserver 168.95.1.1#53
Feb 14 10:57:10 WAN Connection: Fail to connect with some issues.
Feb 14 10:57:10 notify_rc : stop_nat_rules
Feb 14 10:57:10 stop_nat_rules: apply the redirect_rules!
Feb 14 10:57:14 pppd[457]: Connection terminated.
Feb 14 10:57:14 pppd[457]: Sent PADT
Feb 14 10:57:14 pppd[457]: Modem hangup
Feb 14 10:57:59 pppd[457]: Timeout waiting for PADO packets
Feb 14 10:57:59 pppd[457]: Unable to complete PPPoE Discovery

RT-N16跟P874我都各換過一台了
結果都一樣無預警斷線
請大大幫忙看看哪裡有問題

以下為重新插拔P874後RT-N16時擷取
Feb 14 16:30:56 pppd[457]: PPP session is 8266 (0x204a)
Feb 14 16:30:56 pppd[457]: Connected to 00:90:1a:a3:48:1f via interface eth0
Feb 14 16:30:56 pppd[457]: Using interface ppp0
Feb 14 16:30:56 pppd[457]: Connect: ppp0 <--> eth0
Feb 14 16:30:57 pppd[457]: PAP authentication succeeded
Feb 14 16:30:57 pppd[457]: peer from calling number 00:90:1A:A3:48:1F authorized
Feb 14 16:30:57 pppd[457]: local IP address 59.127.182.56
Feb 14 16:30:57 pppd[457]: remote IP address 168.95.98.254
Feb 14 16:30:57 dnsmasq[471]: read /etc/hosts - 3 addresses
Feb 14 16:30:57 dnsmasq[471]: using nameserver 8.8.8.8#53
Feb 14 16:30:57 dnsmasq[471]: using nameserver 168.95.1.1#53
Feb 14 16:30:57 notify_rc : start_nat_rules
Feb 14 16:30:57 start_nat_rules: apply the nat_rules!
Feb 14 16:30:57 notify_rc : stop_upnp
Feb 14 16:30:57 notify_rc : start_upnp
Feb 14 16:30:57 rc_service: start_upnp is waitting stop_upnp...
Feb 14 16:30:57 miniupnpd[786]: received signal 15, good-bye
Feb 14 16:30:58 syslog: SNet version started
Feb 14 16:30:59 miniupnpd[874]: HTTP listening on port 36643
Feb 14 16:30:59 miniupnpd[874]: Listening for NAT-PMP traffic on port 5351
Feb 14 16:31:01 WAN Connection: WAN was restored.
Feb 14 16:31:01 notify_rc : start_nat_rules

然後就順利可以上網了
問題就是一定要跑去插拔一次...