# A Survey on Efforts to Evolve the Control Plane of Inter-Domain Routing
###### Abstract  
The Internet's default inter-domain routing protocol is the Border Gateway Protocol (BGP). With the BGP, dozens of thousands of Autonomous Systems (ASs) exchange network layer reachability information to manage connectivity among them. The BGP was introduced in the early stages of the Internet, and although the BGP is one of the most successful protocols, new desirable features have been difficult to incorporate into the network over the decades. Thus, this paper classifies previous works to evolve the control plane of inter-domain routing into three types of approaches: brand new design; incremental improvement; inter-domain communication. The main goal of this paper is to provide an understanding of what approaches have been taken to evolve the inter-domain routing control plane. This survey also discusses why the control plane's issues are hard to evolve and future perspectives for that topic.  
Board Gateway Protocol; control plane; Internet; Software-Defined Networking +
Footnote †: journal: Information Information  
Points (IXPs). They have been increasing the path diversity of the Internet, where CDNs and IXPs introduced additional AS connectivity to intensify Internet traffic among ASs [13; 14].  
Nonetheless, the BGP's destination-based forwarding paradigm limits the granularity of distributing network traffic among the multiple paths of the current Internet topology. Hence, the BGP is not capable of exploring the full potential of path diversity in the current Internet, because it computes just one \"best\" next hop for each network prefix. New promising technologies such as 5G [4] and the Internet of Things (IoT) [1] have very ambitious requirements (for example, low latency and high bandwidth links) that will stress the network's capabilities, especially in the inter-domain environment. Addressing those network requirements within an Internet not designed to support them is a challenging task. Therefore, new network architectures and technologies have to emerge to explore the full potential of the current Internet infrastructure [15].  
There are many surveys of the BGP that describe its issues, for example the BGP anomaly [16], security [17; 18], the expressiveness and safety of policies [19], transient loops [20], scalability [21], low convergence [22], and others. However, as far as we know, this is the first survey of inter-domain routing to focus on the control plane of the inter-domain routing. Although the Internet relies mostly on the BGP control plane for inter-domain routing, this survey also includes approaches to change the control plane that goes beyond the BGP.  
Thus, the contribution of this survey is providing an original classification, i.e., to evolve the control plane of the inter-domain routing. In addition, this paper discusses the challenges for the evolution of current and new control planes. The remaining structure of the paper is organized as follows: Section 2 depicts the related surveys. Section 3 provides an overview of important concepts used in inter-domain routing, such as the BGP decision process and traffic engineering tools of the BGP, and others. Section 4 presents the challenges of making new solutions for the control plane of the inter-domain. Section 5 classifies the previous works to evolve the control plane; Section 6 discusses and reports the lessons learned from this survey. Section 7 provides the final thoughts of this survey.