当数据再被往下传输的时候,就变成了packet,即“包”的意思。在这一层,Segment会被加上IP头部信息,然后就可以在三层传输了,而工作在三层的路由器会根据目的IP地址来转发这些”包“。 在往下,数据就会被加上MAC地址信息,名称就变成了Frame,”帧“。在这一层,就是交换机的世界了,交换机通常查找MAC地址表项来转发...
Next Header:有 extension header 就用来指向下个 header 的位置,否则就是上层包(TCP、UDP)头部的位置。 Hop Limit:跳数限制,跟 IP 包的生存时间有关。 Source Address:源 IP 地址。 Destination Address:目标 IP 地址。 再来看看TCP 包segment: 图片来源:http://www.tcpipguide.com/free/t_TCPMessageSegment...
= Header Length: 32 bytes (8) # 数据偏移为8,8*4字节=32字节 Flags: 0x002 (SYN) Window: 64240 [Calculated window size: 64240] Checksum: 0x5bcf [unverified] [Checksum Status: Unverified] Urgent Pointer: 0 Options: (12 bytes), Maximum segment size, No-Operation (NOP), Window scale, ...
Options(0 - 320 bits): Use the Options field if you want to include TCP functions that don’t belong in the general header, for example if you want to define the maximum segment size. The length of the options must always be a multiple of 32, otherwise zero-bit padding is required. ...
最大的Packet长度是1500字节,IP Header的长度是20个字节,那么Segment分段的最大长度是1480个字节。而TCP Header通常是20个字节,那么分段中最大数据长度是1460个字节,也就是1500个字节减去20个字节的IP Header长度和20个字节的TCP Header长度,也就是1460个字节数据长度。
TCP Segment structure – TCP segment consists of data bytes to be sent and a header that is added to the data by TCP as shown: The header of a TCP segment can range from 20-60 bytes. 40 bytes are for options. If there are no options, header is of 20 bytes else it can be of ...
使用NDIS_TCP_LARGE_SEND_OFFLOAD_NET_BUFFER_LIST_INFO的TcpHeaderOffset成员中的字节偏移量来确定 TCP 标头的位置,从数据包的第一个字节开始。 将与每个 LSOv2NET_BUFFER_LIST结构关联的NET_BUFFER结构的数量限制为一个。 备注 这是对支持 LSOv2 的微型端口驱动程序的新要求。 LSOv1 微型端口驱动程序...
3.2 IP Header / IP首部 34 3.3 IP Routing / IP路由选择37 3.4 Subnet Addressing / 子网寻址42 3.5 Subnet Mask / 子网掩码43 3.6 Special Case IP Addresses / 特殊情况的IP地址 45 3.7 A Subnet Example / 子网示例46 3.8 ifconfig Command / ifconfig命令47 3.9 netstat Command / netstat命令 49 3....
重传且未收到 ack 的 segment 数 / 整个连接的总重传 segment 次数。 https://unix.stackexchange.com/questions/542712/detailed-output-of-ss-command (Retransmitted packets out) / (Total retransmits for entire connection) add more TCP_INFO components ...
The window size may reduce when a connection is established to a computer that supports extended TCP head options, such as Selective Acknowledgments (SACKS) and Timestamps. These two options increase the TCP header size to more than 20 bytes, which results in less room for data....