Читать книгу CCNP Enterprise Certification Study Guide: Implementing and Operating Cisco Enterprise Network Core Technologies - Ben Piper, David Higby Clinton - Страница 43

You should be familiar with TCP's famous three-way handshake. Its purpose is to allow both sides to establish initial sequence numbers. Here's how it works:

1 Node A sends Node B a segment with the synchronize (SYN) flag set, along with its initial sequence number (ISN), which is usually random.

2 Node B responds with a SYN and its own ISN, which is different from Node A's ISN. Node B also sends an ACK to acknowledge Node A's initial SYN.

3 Node A acknowledges Node B's SYN by sending an ACK.