每分鐘字數
22
Jonzkuhh
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速度
Encapsulation is the process of adding headers to data as it moves down the TCP/IP layers. Each layer adds information needed for communication. The transport layer adds TCP or UDP headers with port numbers, creating segments. The internet layer adds IP headers, creating packets. The network access layer adds MAC headers and trailers, creating frames ready for transmission. When the receiving device gets the frame, the reverse process called decapsulation begins. The frame header is removed, then the packet header, and finally the segment header until the original data reaches the application. This layered approach allows networks to operate efficiently and makes troubleshooting easier because engineers can isolate problems at a specific layer. CCNA students must understand encapsulation thoroughly because it explains how all network communication functions internally.