# Neighbor Session Solutions for Integrated Routing Protocols
## 4 Modeling Protocol Integration Solution Classes
### PISC 3--L3 Transport, Multiple Adjacencies
#### 4.1.1 Sending Part
Its design, independent of the protocols used, allows it to be adapted to completely different types of networks from those for which it was designed. Since the third class of the protocol integration solution came out the worst in the comparison, the current dual-stack routing protocols that we classify based on their properties into this class could benefit from adapting the properties of the PISC 2. Therefore, the goal of further research could be, for example, redesigning protocols such as EIGRP and OSPFv3 into the PISC 2 and then comparing the redesigned protocol with the original model. ## 8 Conclusions

The emergence of new trends in computer networks, as well as the use of routing protocols in areas other than traditional computer networks, raises many questions from the point of view of routing protocol design. Our interest was mainly attracted by the question of supporting multiple network protocols in the routing protocol and the methodof solving the transport for the transmission of routing information. Since our department has experience in the development of an open implementation of the EIGRP routing protocol, the greatest inspiration comes from the design of this protocol as well as from other unique routing protocols such as IS-IS. The main goal of the research presented in this paper was to propose recommendations for designing dual-stack IP routing protocols. As the area of routing protocol design is extensive, we proceeded to narrow the field of research. Based on the analysis of the available research papers reviewed in the introduction, we focused on the support of multiple network protocols from the point of view of the protocol used for the transport of routing information and on the issue of the number of neighbor sessions, specifically for the area when multiple network protocols are deployed in the network, as this issue has not been resolved so far. Based on further analysis, we managed to identify four possible classes of combinations based on a number of neighbor sessions and protocols used for the transport of routing messages, which were introduced as Protocol Integration Solution Classes (PISCs) in Section 3. The proposed PISC classes have never been formally introduced in the research community before, based on our analysis of related works presented in the Introduction section. To be able to propose recommendations for routing protocol design, we had to rigorously compare the proposed PISC with others to clearly define the best class. As a formal method for model creation, we selected colored Petri nets as the best candidate for modeling each PISC class. We then proceeded with each PISC model creation using CPN tools, and the whole process is introduced in Section 4. Each model can be considered an advance in the research field of routing protocols; based on our related works analysis presented in the Introduction, no work has been published yet presenting the models of each PISC class. Because each model is comprehensive and has been thoroughly verified using state space analysis proof, which is presented in Sections 5 and 6, the presented models can be further used by researchers to aid in routing protocols design. For example, if the researcher wants to introduce a new feature or modify the behavior of existing ones, they can extend or modify the chosen model and, by state space analysis verification, test the introduced modifications. As a comparison method for selecting the best PISC based on the created models, we chose a number of simulation steps. According to this criterion, the best PISC class that should be considered for further dual-stack routing protocol design is the PISC 2 as presented in Section 7, with other recommendations from our research. As additional possibilities for expansion and future research based on the results of this work, we see the possibility of applying the recommendations to the design change in the current dual-stack routing protocols belonging to PISC 3, such as EIGRP and OSPFv3, as this class was proven to be the least efficient one.