路由器的部分配置如下: Class-map match-any GOLD match ip precedence ef class-map match-any SILVER Match ip dscp af31 Policy-map Branch Class GOLD Priority percent 20 Class SILVER bandwidth percent 15 random-detect dscp-based interface Serial0/1 description PPP link to BRANCH bandwidth 1536 ip address 10.200.40.1 255.255.255.252 encapsulation ppp 路由器配置VOICE数据流到优先级队列中,但发现并没有起到作用,可能什么原因?()