# An Architecture to Manage Incoming Traffic of Inter-Domain Routing Using OpenFlow Networks
## 1 Introduction  
The Internet is a collection of tens of thousands of independently operated networks. In the jargon of the Internet, these networks are called Autonomous Systems (ASes). An AS can be an Internet Service Provider (ISP), a campus, a content provider, or any other independently operated network. All these ASes can connect with each other as they execute an inter-domain routing protocol to exchange network reachability information. The Border Gateway Protocol (BGP) [1] is the current standard for inter-domain routing on the Internet and provides reachability information among the ASes. BGP is one of the most successful protocols on the Internet. However, many researchers have indicated issues related to BGP since its inception, e.g., the lack of end-to-end service guarantees, long convergence time, and security issues [2]. Furthermore, it is well known that BGP suffers from the process of \"ossification\", where the architecture becomes very dependent on the protocol, and new features are inherently hard to introduce into the network. For the BGP, the ossification is due to economic reasons combined with the fact that backward compatibility has to be assured since there is no flag day to switch to a new architecture. Thus, all BGP appliances have to execute the same version of the protocol to operate appropriately, or anomalies in the network may occur (e.g., BGP black holes). Hence, a new feature for the BGP protocol has to have a minimum integration within heterogeneous networks and interoperate through different administrative domains (e.g., the Internet). These requirements have frustrated new proposals to evolve BGP and the ecosystem of inter-domain routing [3]. Although the BGP has some mechanisms to control inbound traffic, for example, Multi-Exit Discriminator (MED), Communities, AS-Path Prepending and others, the effectiveness of applying these mechanisms are unclear and are also not guaranteed once they are indirect approaches. Thereby, BGP inbound traffic control mechanisms try to influence other ASes to change the preference regardingroutes, and often the desired traffic distribution cannot be achieved. Furthermore, another difficulty for the manipulation of inter-domain traffic is the BGP's destination-based forwarding paradigm [1]. This approach limits the granularity of selecting the traffic once the decision of forwarding IP packets only relies on the information of the IP destination header field. One promising approach to enable network architectures to evolve is Software Defined Networking (SDN). SDN emerged as a new paradigm that allows network engineers to elaborate new network designs and includes desirable features for this evolution such as open programmable interfaces at networking devices, the separation between control and forwarding planes, and innovation occurs in applications executed inside the control planes [4; 5; 6; 7]. A notable SDN technology is the OpenFlow protocol (OF). OF is an open programmable interface for SDN that gained momentum in academia and industry over the last decade [8]. OF is flow-oriented, meaning that the sequence of packets identified by a set of common header fields follows a given path. Thus, OF can provide fine-grain forward capabilities to the network by matching multiple fields of TCP/IP. This work applies SDN concepts and uses the OpenFlow capabilities to compose a new network architecture to evolve inter-domain routing systems. Here, the proposal is to investigate an architecture to manage inbound traffic in an inter-domain routing system using SDN technologies. The main idea was to depict new mechanisms to be deployed in transit ASes (often an ISP) that can allow a customer AS to execute control tasks for managing how incoming traffic can reach its network.