ICMP的标识符和序列号的本质是什么？

Question

4 0.471102408 10.24.70.66 115.239.210.27 ICMP 1066 Echo (ping) request id=0x1a20, seq=11/2816, ttl=64 (reply in 8)

Internet Control Message Protocol
Type: 8 (Echo (ping) request) //request 是8 ，reply 是0
Code: 0

Checksum: 0x3da0 [correct] // 校验码
[Checksum Status: Good] // 防止有人而已篡改
Identifier (BE): 6688 (0x1a20)
Identifier (LE): 8218 (0x201a)
Sequence number (BE): 11 (0x000b)
Sequence number (LE): 2816 (0x0b00)
[Response frame: 8]
Timestamp from icmp data: Apr 1, 2018 17:27:53.000000000 CEST
[Timestamp from icmp data (relative): 0.860325254 seconds]
Data (1016 bytes)
Data: 90200d0000000000101112131415161718191a1b1c1d1e1f...
[Length: 1016]

8 0.828236910 115.239.210.27 10.24.70.66 ICMP 1066 Echo (ping) reply id=0x1a20, seq=11/2816, ttl=46 (request in 4)
上面的这个是ICMP的request and replay

Internet Control Message Protocol
Type: 0 (Echo (ping) reply)
Code: 0
Checksum: 0x45a0 [correct]
[Checksum Status: Good]
Identifier (BE): 6688 (0x1a20)
Identifier (LE): 8218 (0x201a)
Sequence number (BE): 11 (0x000b)
Sequence number (LE): 2816 (0x0b00)
[Request frame: 4]
[Response time: 357,135 ms]
Timestamp from icmp data: Apr 1, 2018 17:27:53.000000000 CEST
[Timestamp from icmp data (relative): 1.217459756 seconds]
Data (1016 bytes)
Data: 90200d0000000000101112131415161718191a1b1c1d1e1f...
[Length: 1016]

我在抓包的过程中发现这个iddentifier 是一样的，但是这个Sequence number却是不一样的，这两个参数的本质是什么？

Answer 1

题主问题主要针对的是 PING 报文(回显)。
标识符和序列号用于匹配回显应答和回显请求。
具体来说，标识符确定该报文的发送者， 而序列号关联对应的请求报文和应答报文(请求报文和其对应的响应报文的序列号相同)。
参考：
ICMP 协议： https://blog.csdn.net/yanglingwell/article/details/82989152