MP捆绑接口shutdown和拔线丢包数量不一致

MSR3640双上行到友商设备，MSR3640的Serial1/0、Serial3/0加入到MP-group0里边，  Serial1/1、Serial3/1 加入到MP-group1里边，跟对端采用ospf动态路由。两个MP组都转发数据。

1、在对端设备上长ping msr3640的loopback口地址或业务口的地址或业务口地址，如果采用敲命令的方式分别shutdown掉两个MP组里边任意一个端口，此时对端ping过来会丢2个包后恢复，如果采用分别直接拔掉两个MP组里边任意一个端口的方式，对端ping过来会丢7-8个包左右。

2、将一个MP组里边2个端口全部down掉，不管是采用shutdown的方式还是拔线的方式，均是丢2个包。

设置相同环境，进行debugging查看发送包信息

Shutdown和拔线有些区别。

接口shutdown，会在serial接口down之前向对端发送terminate request，对端收到报文就将对应线路移出mp group了。切换比较快。

[H3C-Serial2/0]shutdown

[H3C-Serial2/0]

*Oct 19 16:50:02:415 2021 H3C PPP/7/FSM_EVENT_0:

  PPP Event:

      Serial2/0 LCP Close Event

      State opened

*Oct 19 16:50:02:415 2021 H3C PPP/7/FSM_STATE_0:

  PPP State Change:

      Serial2/0 LCP: opened --> closing

*Oct 19 16:50:02:415 2021 H3C PPP/7/FSM_PACKET_0:

  PPP Packet:

      Serial2/0 Output LCP(c021) Packet, PktLen 8

      Current State closing, code TermReq(05), id 17, len 4

……

%Oct 19 16:50:02:416 2021 H3C IFNET/5/LINK_UPDOWN: Line protocol state on the interface Serial2/0 changed to down.

*Oct 19 16:50:02:417 2021 H3C PPP/7/MP_EVENT:

  PPP MP Event:

      MP-group1: Serial2/0 has left from the bundle which has 1 sub-channels now!

%Oct 19 16:50:02:417 2021 H3C IFNET/3/PHY_UPDOWN: Physical state on the interface Serial2/0 changed to down.

接口拔线，对设备来说是不可预知的接口down，接口down之前无法发出term req，所以对端在接口没有物理down（有传输）的情况下不能马上感知到，要等该serial保活超时。H3C的serial ppp保活默认10s * 5。

建议尝试在拔线之前，同时登陆两端设备，拔线后分别dis ppp mp看下成员口状态，如果有一端dis ppp mp持续有两个serial是active的，持续几十秒之后才有一个serial变为inactive，那就是上述的原因。

%Oct 19 16:47:16:693 2021 H3C IFNET/5/LINK_UPDOWN: Line protocol state on the interface Serial2/0 changed to down.

%Oct 19 16:47:16:693 2021 H3C IFNET/3/PHY_UPDOWN: Physical state on the interface Serial2/0 changed to down.

*Oct 19 16:47:16:693 2021 H3C PPP/7/EXTERNAL_EVENT_0:

  PPP External Event:

      Serial2/0: PPP daemon receive interface down event!

*Oct 19 16:47:16:693 2021 H3C PPP/7/FSM_EVENT_0:

  PPP Event:

      Serial2/0 LCP Lower Down Event

      State opened

*Oct 19 16:47:16:693 2021 H3C PPP/7/FSM_STATE_0:

  PPP State Change:

      Serial2/0 LCP: opened --> starting

*Oct 19 16:47:16:693 2021 H3C PPP/7/FSM_EVENT_0:

  PPP Event:

      Serial2/0 LCP Close Event

      State starting

*Oct 19 16:47:16:693 2021 H3C PPP/7/FSM_STATE_0:

  PPP State Change:

      Serial2/0 LCP: starting --> initial

*Oct 19 16:47:16:694 2021 H3C PPP/7/MP_EVENT:

  PPP MP Event:

      MP-group1: Serial2/0 has left from the bundle which has 1 sub-channels now!