问一个华为数据包二次切片的问题

很久以后？！

问个ICMP分片的问题。R1和R2之间的链路MTU是1500字节，R2和R3之间的MTU是700字节。我设置了一个2000字节的ICMP包，可以看到在R1和R2之间正常分片，先其他分片，最后一片才是ICMP片，，在R2和R3之间抓包，可以看到先ICMP分片，再是其他分片，感觉很奇怪，而且没有回包。请问下怎么样才能实现二次分片？
[AR1]ping 23.1.1.3
  PING 23.1.1.3: 56  data bytes, press CTRL_C to break
    Reply from 23.1.1.3: bytes=56 Sequence=1 ttl=254 time=90 ms
    Reply from 23.1.1.3: bytes=56 Sequence=2 ttl=254 time=80 ms
    Reply from 23.1.1.3: bytes=56 Sequence=3 ttl=254 time=60 ms
    Reply from 23.1.1.3: bytes=56 Sequence=4 ttl=254 time=40 ms
    Reply from 23.1.1.3: bytes=56 Sequence=5 ttl=254 time=40 ms


  --- 23.1.1.3 ping statistics ---
    5 packet(s) transmitted
    5 packet(s) received
    0.00% packet loss
    round-trip min/avg/max = 40/62/90 ms





[AR1]ping -s 2000 23.1.1.3
  PING 23.1.1.3: 2000  data bytes, press CTRL_C to break
    Request time out
    Request time out
    Request time out
    Request time out
    Request time out


  --- 23.1.1.3 ping statistics ---
    5 packet(s) transmitted
    0 packet(s) received
    100.00% packet loss