This thesis report presents a method to analyze the communication architecture for the Intelligent Transportation Systems (ITS). The report also includes a case study on ASN.1 notation and analysis of its encoding rules. Included in the report is also: (i) accompanying instruction on how to use ASN.1 compilers to produce the C/C++ message encoder/decoder, and (ii) analysis of Non-IP communications of Communication Access for Land Mobiles (CALM-FAST) protocol stack in ITS. The thesis is a part of the research project entitled “SCOOP”, a joint project between SCANIA CV AB and KTH. The purpose of this thesis is to contribute to the ultimate goal, which is to equip a vehicle with necessary hardware and software technology to provide a platooning behavior in the GCDC 2011 competition. This goal is achieved by the means of wireless communication system for both vehicle to vehicle and vehicle to road side units communications in the platoon. Overall, this thesis introduces the important usage of ASN.1 in implementation of cut-edge telecommunication systems especially in V2V and V2I communication; and clarifies the CALM-FAST protocol stack in mobile nodes. / Kartlägga CALM-FAST protokollet och hur det användes tillsammans med den i tävlingen GCDC 2011 fastslanga kommunikationsprotokollet. GCDC var ett tävling i kooperativ körning arrangerad och initierad av Hollänska TNO och gick ut på att få fordon att agera tillsammans beserat på information sänt via WLAN 802.11p. ASN.1 användes och ingick i analysen.