In the ACM Turing award lecture given by the awardees (Dr. Vinton Cerf and Dr. Bob Khan), they discussed several of their opinions regarding the evolution of the Internet. They also discussed challenges and future trends of the Internet architecture.
As seen in previous literatures [1,2,3,4], the Internet follows an end-to-end set of policies that enables communication between two hosts. To support a wide variety of services, functions should be built on the application layer rather than on the network itself .
According to Cerf and Khan, the motivation for the initial Internet architecture (that is to establish communication between two processes in different networks) is different to what is the actual need of the users today. As for computer scientists, the Internet is a medium for computational purposes, in a wide range of users, the Internet is used to share files and resources. Although the initial motivation defined by the authors is not the case today, the Internet remains stable. The basic architecture has evolved by introducing different layers over the network. It is said in the interview that, if they have foreseen this set of requirements, the basic principles or architecture of the Internet might be different from what we now have today.
The lecture also mentions different challenges that the Internet is facing today. One of such issue is on network security examples of which are spam and viruses. Improvements in security side are working in parallel with the improvements in the network. Another issue mentioned is on the existence of outgrowing number of mobile devices connected to the internet. It’s an issue because these devices are not stationary in position and are not always connected to the Internet. This issue was not foreseen in the original Internetwork architecture because at that time the hosts were most of the time connected, and topology of the network is almost fixed (aside from additional hosts in the network). Which became one of the future trends they mentioned. The problem of mobile hosts extends to the problem of interplanetary Internet. Although TCP/IP works fine ( allows fast and reliable communication between processes) in terrestrial Internet, it is not effective in space for the following problems. The first problem is the physical distance between two communicating processes. Second, planets or objects in space are constantly moving. Third, TCP is not well suited for file transfers. The details of interplanetary internet (IPN) is posted here.
 Marjory S. Blumenthal and David D. Clark. 2001. Rethinking the design of the Internet: the end-to-end arguments vs. the brave new world. ACM Trans. Internet Technol. 1, 1 (August 2001), 70-109. DOI=10.1145/383034.383037 http://doi.acm.org/10.1145/383034.383037
 Fred Baker, Noel Chiappa, Donald Eastlake, Frank Kastenholz, Neal McBurnett, Masataka Ohta, Jeff Schiller and Lansing Sloan, International Engineering Task Force (IETF), Request For Comments 1958, 1996
 Vinton G. Cerf and Robert E. Icahn. 2005. A protocol for packet network intercommunication.SIGCOMM Comput. Commun. Rev. 35, 2 (April 2005), 71-82. DOI=10.1145/1064413.1064423 http://doi.acm.org/10.1145/1064413.1064423