This layer of the DoD Model is also sometimes called Transport in some books but the proper name is Host-to-Host as per the RFC document.
The host-to-host layer provides for reliable end-to-end communications, ensures the data’s error-free delivery, handles the data’s packet sequencing, and maintains the data’s integrity.
It is comparable to the transport layer of the OSI model.
Reference(s) used for this question: http://en.wikipedia.org/wiki/Internet_protocol_suite and http://technet.microsoft.com/en-us/library/cc786900%28v=ws.10%29.aspx and KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 3: Telecommunications and Network Security (page 85).