## 2 Materials and Methods
### Neighbor RSU Discovery
Then, using ant packets, RSUs regularly evaluated the connectivity of the street segments between adjacent RSUs, and sent the evaluation information to the SDN server, which has the global information of each street segment in the simulation area. According to this evaluation information, the SDN server can calculate the optimal anchor path from the sending vehicle node to the destination vehicle node, and feed it back to the sender. Based on this path, the sender forwards the packet to the destination vehicle. Experimental results show that the proposed scheme can effectively improve the packet delivery rate compared with other typical routing schemes. In future work, we will focus on the security of routing to prevent malicious attacks from hackers. Conceptualization, G.Z. and H.Z. ; methodology, J.L. ; software, H.Z. ; validation, J.L., L.J. and H.Z. ; formal analysis, L.J. ; investigation, J.L. ; resources, L.J. ; data curation, H.Z. ; writing--original draft preparation, H.Z. ; writing--review and editing, H.Z. ; visualization, J.L. ; supervision, G.Z. ; project administration, G.Z. ; funding acquisition, G.Z. All authors have read and agreed to the published version of the manuscript. This research was funded by the National Natural Science Foundation of China (No. 61971245) and Doctoral Research Foundation of Nantong University (No. 135422630029). Data Availability Statement: Data sharing is not applicable to this article. The authors declare no conflict of interest. ## References

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