Which PDU format is transmitted from the transport layer to the internet layer in TCP/IP?

The format of the Protocol Data Unit (PDU) transmitted from the transport layer to the internet layer in TCP/IP is referred to as a segment. When data is transmitted through the TCP/IP model, it moves through layered protocols, and each layer adds its own header to the data it receives.

At the transport layer, which encompasses protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol), the data is organized into segments. These segments include a header that contains control information necessary for the delivery of the data, such as port numbers and sequence numbers.

Once the transport layer has prepared the segment, it is then handed off to the internet layer. The internet layer, in turn, processes the segment by encapsulating it into packets. This encapsulation involves adding its own IP header, which contains information necessary for routing the packet through the network.

This transfer from segment at the transport layer to packet at the internet layer is crucial for ensuring that data is correctly formatted and routed across the network, which is an essential function of the TCP/IP model.