## 6 Conclusions  
As a result, a custom extension for the EviNS software framework has been developed to address the task of underwater acoustic communication networking. This extension includes a protocol stack at the data link layer consisting of DACAP and T-Lohi protocols, aimed at reducing or eliminating collisions by managing access delays to the propagation medium during packet transmission. Additionally, the network layer protocol stack includes DPFloading and ICRP protocols to facilitate the formation of modem groups into a network and ensure reliable packet transmission within this network. The testing results of the developed algorithms suggest that the use of these network and data link layer protocols increases the probability of successful packet transmission within the network (achieving 100% compared to 60-70% without protocol usage), albeit at the expense of data exchange speed (reduced from 120 bits/s to 60 bits/s for Evologics modems). This reduction in speed is attributed to the increase in average access delay to the propagation medium. This development can be further enhanced by incorporating software modules that enable the integration of modems from various manufacturers into the software framework. Ultimately, it could be utilized in implementing concepts related to the Internet of Things in the maritime domain or in group management of autonomous unmanned underwater vehicles. Conceptualization, K.K. and A.K. ; methodology, K.K., O.K. and V.K. ; software, M.D., T.A. and V.K.-A. ; validation, O.K. ; formal analysis, V.K. ; investigation, O.K., M.D. and T.A. ; resources, K.K. ; data curation, O.K., M.D., T.A. and V.K.-A. ; writing--original draft preparation, V.K. ; writing--review and editing, K.K., A.K. and V.K. ; visualization, M.D. ; supervision, K.K. ; project administration, A.K. ; funding acquisition, A.K. All authors have read and agreed to the published version of the manuscript. This research was funded by Sevastopol State University, which provided an internal grant (ID 42-01-09/241/2022-2). The work was also supported by the Russian Ministry of Education and Science, project FEFM-2024-0015. Figure 22: The probability of successful transmission of a packet within a network using network communication protocols and without such protocols. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** The raw data supporting the conclusions of this article will be made available by the authors on request. **Acknowledgments:** The authors would like to express their gratitude towards the team at Evologics in Germany for providing an open-source software framework under the GNU GPL/MIT license. The authors would like to express their gratitude towards Latena J.S.C in Russia for providing access to the hydroacoustic modem emulator (model 104). **Conflicts of Interest:** The authors declare no conflicts of interest. **Appendix A**  
```
1: If you received RTS signal and it's for you then
2: send CTS signal;
3: else set backoff state to true;
4: while in backoff;
5: if ack; backoff end
6: else compute T; backoff end after T
7: When application invokes MAC send
8: if now state is backoff;
9: if ack; backoff end
10: else compute T; backoff end after T;
11: else send RTS; wait to CTS
12: if receive RTS or CTS not for you, then
13: cancel data transmission; set backoff state and goto line 8;
14: else transmit data; go to idle state
```  
**Algorithm A2** Pseudocode for T-Lohi protocol  
```
1: if you receive a contention tone (CTD) while idle
2: set blocking state to true; unset at end of current frame
3: When application invokes MAC send
4: if blocked; wait for end of frame and attempt in next RP. 5: else transmit contention tone; wait for end of current CR. 6: if (contender count (CTC) > 1)
7: Compute \(w\) uniformly from [0,CTC]; backoff \(w\) CR(s)
8: if CTD; while in backoff
9: set blocking state to true; unset at end of frame
10: wait for end of frame and attempt in next RP.