The goal of Cooperative Intelligent Transportation Systems (ITS) is to enhance road safety, traffic efficiency, and comfort of road users based on Vehicle-to-Vehicle, Vehicle-to- Roadside, and Vehicle-to-Central communications over diverse media such as DSRC, Wi-Fi, 3G, WiMAX, and LTE. IPv6 is the most promising technology that enables a convergence of such different communications over diverse media. This paper is about investigating the issues regarding IP-communications over DSRC band. The investigation is made through field test experiments using communication devices equipped with hardware interfaces for different media as well as an IPv6 stack. Based on our field test results, we discuss the issues and some potential solutions towards achieving sufficient perfomance of IPv6 communications over DSRC band.