MSR3620 dialer接口总是up down

V7 MSR3620 dialer接口总是Up down，物理口GE0/0关联dialer 1，dialer接口down时观察物理口GE0/0是UP的，现在问题是dialer一down缺省路由就失效了，下面业务就上不了网了，有什么办法让dialer接口始终UP？

interface Dialer1

 bandwidth 1000000 

 mtu 1492 

 ppp chap password cipher $c$3$WK3Rr5WkAZYRGONF853Y8lmbuGI+gcEdqkxh 

 ppp chap user 053104157356

 ppp ipcp dns admit-any

 ppp ipcp dns request

 ppp pap local-user 053104157356 password cipher $c$3$oGn4+C5GNB+v0qGSrX/PDBoLfpR/mKsNSlsu

 dialer bundle enable 

 dialer-group 1 

 dialer timer idle 0

 ip address ppp-negotiate 

 tcp mss 1200 

 nat outbound #

[JN-7F2-31-RT-H3620]dis cu int g0/0 

# interface GigabitEthernet0/0 

 port link-mode route

 description WAN 

 combo enable copper

 pppoe-client dial-bundle-number 1

 #