First the paper considered the problems of the existing Internet architecture. Because of the existing architecture was designed many years ago, the goal of the design is simple. The goal is enable communication between two hosts. That is to say, the Internet carries out its task if two hosts can communicate with each other through it.
 
But nowadays, more and more requests are put forward. For example, people want Quality of Service (QoS). There are a lot of problems in enterprises, it is getting more and more complex when managing enterprise network. It is hard to implement access control policy. Between autonomous systems and autonomous systems, there are a lot of problems when enforce higher level routing policies. In a word, the Internet is getting harder and harder to use and control.
 
The authors of the paper want to redesign the architecture of the Internet keeping the problems in mind. The authors hope that the problems above could be solved easily. This is the goal of the 4D architecture. 4D stands for data, dissemination, discovery and decision. The data plane of the new designed architecture manipulates the data packets, such as forwarding the packets, calculate check sum and so on. The discovery plane is used to discover the physical components in the network and create logical identifiers to represent them. The dissemination plane provides a communication substrate that connects routers/switches with decision elements. The decision plane makes all decisions driving network control, including reachability, load balancing, access control, security, and interface configuration.
 
This architecture has a lot of advantages. It separates networking logic from distributed systems issues, ensures the internal consistency of the state and robustness, provides better security, and enables enabling of innovation and network evolution.
 
There are also a lot of challenges. So, it needs more and more people struggle for solving problems.