# Neighbor Session Solutions for Integrated Routing Protocols
###### Abstract
Subsequently, during the analysis of the existing integrated protocols, we manage to identify four combinations of the number of created adjacencies and the protocol used to transmit messages of the routing protocol itself. These combinations, referred to in this paper as Protocol Integration Solution Classes (PISCs), are, together with the services, necessary to establish the adjacencies and transfer information described in Section 3. The research presented in this paper aims to clarify which of the PISCs is the most effective and subsequently to propose general recommendations that can be used for the future design and implementation of routing protocols, which are suitable for deployments in the environment of networks using multiple network protocols and address systems. To achieve this goal, we analyze the formal methods described in our previous paper [18], which reveal that one of the most suitable methods is using colored Petri nets (CPNs). Our analysis is confirmed by the usage of colored Petri nets or general Petri nets in several network and routing related areas: in the IP routing protocols area for the verification of the Open Shortest Path First (OSPF) protocol vulnerabilities [19], for the protocol conformance test of the OSPFv3 protocol [20], or for the verification of the Border Gateway Protocol (BGP) via decomposition [21]; for general communication protocol validation [22, 23] and improvement in the multicast routing protocol PIM-SM [24]; in wireless sensor networks for the modeling of the new routing protocol, ensuring an optimal tradeoff between the computational cost and source-location privacy [25], and to model and analyze the behavior of the vector-based forwarding routing protocol [26]; in the cloud computing area to generate SaaS inside the cloud environment from a multiview model using PNML [27] or to create a reconfigurable protocol stack for the cloud computing control system [28]; or in security for simulation platform creation, which could be used for designing defense against internet end-systems targeted attacks [29], for auto-analysis tools for security protocols [30], for the security of the IPv6 protocol used in IoT networks [31], and for the analysis and improvement in vehicle ethernet protocol security [32]. Our department has experience with routing protocols thanks to developing an open implementation of the Enhanced Interior Gateway Routing Protocol (EIGRP). Therefore, the decision is made to start the modeling with the third PISC class since the EIGRP routing protocol belongs to this class. As part of our previous research, we perform a deeper analysis of the EIGRP protocol design, which was described in our previous papers [33, 34]. We further transform the acquired knowledge into the conceptual model of the third PISC, from which we derive the models of the other classes. The created models of individual PISC are described in detail in Section 4. The design of all the models is verified by the state space analysis described in Section 5. During the design verification phase, the problem of the state space explosion is solved by introducing limiting and synchronization spaces, after which the state space calculation is repeated. To determine which PISC class is superior and should be considered as an example of the dual-stack routing protocol design, the analysis is made to select the criterion to compare the models with each other. The criterion selection process and comparison based on the selected criteria is shown in Section 6. The main goal of this paper is to establish recommendations for the design of the future, as well as modification of the current dual-stack routing protocols. Based on the research presented in this paper, we can surmise that PISC 2 is the most efficient class of the four identified PISC and should be considered the base for further dual-stack routing protocol design.