The Transport layer of the Open Systems Interconnection (OSI) model implementation adds information concerning the logical connection between the sender and receiver. The Transport layer is responsible for establishing, maintaining, and terminating the end-to-end communication between two hosts, as well as ensuring the reliability, integrity, and flow control of the data. The Transport layer uses protocols such as TCP and UDP to provide connection-oriented or connectionless services, and adds headers that contain information such as source and destination ports, sequence and acknowledgment numbers, and checksums . References: : CISSP All-in-One Exam Guide, Eighth Edition, Chapter 5, page 499. : CISSP For Dummies, 7th Edition, Chapter 5, page 145.