isn测试原理

isn测试原理
ISN (Internet Sequence Number) is a protocol used in network communication to establish a reliable and ordered delivery of data packets. It is a 32-bit integer value that provides a unique identifier for each TCP (Transmission Control Protocol) packet sent over the network.
The principle behind ISN is to ensure that data packets arrive at the destination in the correct order and without any loss. Each packet is assigned a sequence number by the sending host, which is incremented for each subsequent packet. The receiving host uses these sequence numbers to reorder the packets and detect any missing or duplicate packets.
The ISN protocol works by maintaining two variables on each end of the network connection: the initial sequence number (ISN) and the next expected sequence number (NESN). The ISN is randomly generated at the start of the connection, while the NESN is initially set to the ISN. As data packets are transmitted, the NESN is incremented to ensure that each packet arrives in the correct order.
Additionally, ISN also helps in preventing certain types of network attacks, such as TCP/IP session hijacking, by making it difficult for an attacker to predict the sequence numbers of future packets.
Overall, ISN plays a crucial role in establishing a reliable and orderly transmission of data packets in TCP/IP networks.。