## 5 Conclusions  
In this study, we aimed to create a software testbed to assess communication protocols for the PHY and MAC layers developed through GNU radio. This testbed should be easy to use, capable of interacting with any traffic generator, and should enable the collection and analysis of PHY-layer monitoring data. To achieve this, the paper outlines how to set up a network environment that can be used for end-to-end testing of both simulation and real channel applications. These network environments are isolated, making them easier to manage and allowing multiple environments on the same machine--which is particularly important when multiple tests are executed simultaneously on powerful servers. The setup and management are implemented in Python to facilitate integration in testing automation, using the Linux kernel's virtual network devices (tun/tap) to feed test traffic into the applications (i.e., transmission chain for SDR) to make it compatible with any network traffic generator. In this paper, we have suggested and examined various methods for obtaining monitoring data from the physical layer. One approach employs only the polymorphic types (PMTs) built into GNU radio, while the other two use the protocol buffer library to improve the efficiency of message generation, serialization, and parsing processes. The PMT method is highly versatile and user-friendly, as it is integrated into the GNU radio runtime and does not necessitate schema definitions. Testing communication protocols generates significant monitoring data that need to be acquired in real-time. It is important to use suitable methods to ensure efficiency and faster messaging. We analyzed the performance of protocol-buffer-based methods in terms of the computation time of the main components, CPU usage in end-to-end tests, and message size. The results showed that the protocol-buffer-based methods outperformed the PMT method in all scenarios considered. In this paper, we have explored the complete evaluation system, covering PHY-layer monitoring, data storage, and visualization. We have demonstrated how to use this system for white box testing of wireless transmission protocols developed with GNU radio. The testbed's capabilities were demonstrated using a complex OFDM duplex transmission system with adaptive coded modulations. Although we have not explicitly addressed the automation of the testing process, it is clear the proposed framework has the potential to facilitate the integration of such functionality with relative ease. Custom traffic generators can be constructed to align with the test suite while implementing testbed management in Python, which allows it to be easily exposed to automation testing frameworks.  
Conceptualization, M.P.S. and Z.A.P.; methodology, M.P.S.; software, M.P.S.; validation, Z.A.P. and M.P.S.; formal analysis, Z.A.P.; investigation, M.P.S.; resources, Z.A.P.; data curation, Z.A.P.; writing--original draft preparation, M.P.S.; writing--review and editing, Z.A.P.; visualization, M.P.S.; supervision, Z.A.P.; project administration, M.P.S.; funding acquisition, Z.A.P. All authors have read and agreed to the published version of the manuscript. This research received no external funding.  
Not applicable.  
Data availability Statement: Data are contained within the article.  
The authors declare no conflicts of interest.