It is our great pleasure to present this special issue of Performance Evaluation (PEVA), on extended versions of six research papers that were presented at the 35th International Teletraffic Congress (ITC 2023), in Torino, Italy. In 2023, ITC returned as a physical meeting after being held three times virtually due to the COVID- 19 pandemic. The paper review and selection process for the conference was very thorough. Each submission received four reviews from program committee (PC) members not in conflict of interest with the authors. At the end of the PC meeting, the conference accepted 9 long papers and 4 short ones, and in an effort to generalize shepherding to all accepted papers, 10 out of the 13 papers were shepherded, which strengthened the submissions making excellent use of the constructive feedback provided by the reviewers. The proceedings of ITC 2023 were subsequently published through IEEEXplore. After the conference, all authors were invited to extend their accepted paper by at least 30% and submit the extension to this special issue. The 6 papers in this PEVA special issue cover exciting developments in performance evaluation on a variety of topics in computer/communication systems. We hope that the readers will enjoy this special issue and find it intellectually stimulating.