# A Survey on Efforts to Evolve the Control Plane of Inter-Domain Routing
## 5 Classification of Efforts for Evolving the Control Plane
### Efforts to Evolve the Control Plane of Inter-Domain Routing
#### 5.2.1 Brand New Design
Although the NIRA's objective was to transform the Internet architecture, it requires the adoption of a new network protocol called the Topology Information Propagation Protocol (TIPP) to work properly. Applying the SDN concepts, the Multi-dimension Link Vector (MLV) [60] presented a new mechanism to exchange the network view. MLV uses the OpenFlow protocol [49] in its data plane elements and enables flexible inter-domain routing in an SDN network federation. MLV is a solution based on a link vector algorithm for representing the inter-domain state of the network. With the exchanging of the link vector data structure and the fine-grained rules provided by OpenFlow, the network operator could make decisions regarding paths combining that information. Despite the fact that MLV was a proposal to evolve inter-domain routing among SDN networks, the link vector data structure imposes scalability concerns. The Route Chaining System (RCS) [61] follows the concept of SDN networks to allow ASs to select routes that do not follow the standard BGP algorithm and explore the possibility of diversity paths of the Internet. RCS focuses on control traffic on transit ASs from the AS source to destinations and also \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Proposal and Authors** & **Concepts** & **Approach** & **Control Plane** & **Explore** \\  & & & **Placement** & **Path Diversity** \\ \hline FBR, [PERSON], [PERSON] [54] & Traditional & Protocol & Distributed & Sourcing routing \\ BARON, [PERSON] et al. [55] & Traditional & Architecture & Distributed & Overlay \\ MBGP, Fujinoki [56] & Traditional & Protocol & Distributed & Alternative routes \\ Multipath BGP, [PERSON] et al. [57] & Traditional & Protocol & Distributed & Alternative routes \\ AMIR, [PERSON] et al. [58] & Traditional & Protocol & Centralized & Sourcing routing \\ NIRA, [PERSON] et al. [59] & Traditional & Architecture and Protocol & Distributed & Sourcing routing \\ MLV, [PERSON] et al. [60] & SDN & Architecture and Protocol & Centralized & Based on flows \\ RCS, [PERSON] et al. [61] & SDN & Architecture & Distributed & Inter-domain negotiations \\ SDI, [PERSON], et al. [62] & SDN & Architecture & Distributed & Inter-domain negotiations \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Classification for proposals to evolve the inter-domain routing with a brand new design. FBR, Feedback-Based Routing; BARON, Bandwidth-Aware Routing in Overlay Networks; MBGP, Multi-Path BGP; AMIR, Another Multipath Interdomain Routing; NIRA, New Internet Routing Architecture; MLV, Multi-dimension Link Vector; RCS, Route Chaining System; SDI, Software-Defined Inter-domain. requires an inter-domain communication layer between ASs to enable the multiple and distributed control planes to be connected to compose the solution. Software-Defined Inter-domain (SDI) routing [62] advances into the inter-domain support of flexible routing policies to forwarding packets, where multiple fields of the IP packet header could be used for matching (flow-level), instead of just using the BGP's destination-based forwarding paradigm. SDI also provides a mechanism to treat a large number of flow table entries required to represent the forwarding fine-grained flows. For the control plane placement, the SDI solution keeps each domain with its own control plane, which computes paths individually. To explore the path diversity between SDI domains, flow schemes are exchanged. Summary: Clean-slate proposals are suitable for a very specific application, when used, and cannot be broadly adopted because they are incompatible with the current control plane of the Internet. In addition to traditional solutions, a new protocol proposal must be executed inside network devices or all network devices that utilize such solutions need to be modified, and such a situation may require CAPEX (CAPital EXenditure) and OPEX (OPerational EXenditure) to be operational.