TOMS: TCP Context Migration Scheme for Efficient Data Services in Vehicular Networks JunSik Jeong ∗ , Yiwen (Chris) Shen † , Jaehoon (Paul) Jeong ‡ , Tae (Tom) Oh § , Junghyun Jun ¶ and Sang Hyuk Son  ∗ Department of DMC Engineering, Sungkyunkwan University, Suwon, Republic of Korea † Department of Computer Science & Engineering, Sungkyunkwan University, Suwon, Republic of Korea ‡ Department of Interaction Science, Sungkyunkwan University, Suwon, Republic of Korea § Department of Information Sciences & Technologies, Rochester Institute of Technology, USA ¶ Department of Computer Science & Engineering, Indian Institute of Technology at Ropar, India  Department of Information & Communication Engineering, DGIST, Republic of Korea Email: {jjs9915, chrisshen, pauljeong}@skku.edu, tom.oh@rit.edu, peterjun@iitrpr.ac.in, son@dgist.ac.kr Abstract—The recent advances in wireless communication techniques have made it possible for fast-moving vehicles to download data from the Internet. For the reliable data upload and download, TCP can be used for vehicular networks. How- ever, TCP requires the connection initialization using three-way handshaking for the data exchange between two end systems over the Internet. Thus, the efficient operation of TCP is important for data services in the vehicular networks. This paper proposes a method of T CP Co ntext M igration S cheme (TOMS) for the enhancement of data services in vehicular networks. TOMS provides vehicles with proactive TCP connection initialization using a moving TCP proxy as a cluster head, which will have the Internet connectivity with a Road-Side Unit (RSU). A cluster member can initiate its TCP connection toward its corresponding TCP end-system (e.g., server and peer) via the TCP proxy within its cluster. The TCP proxy performs the TCP connection set-up for the sake of other cluster member vehicles and acknowledges the received TCP segments toward these vehicles. When the TCP proxy moves out of the communication range of the RSU, it transfers the TCP contexts of other vehicles to another vehicle, which will play the role of a TCP proxy through the proposed TCP context migration scheme. Also, the RSU works as a fixed TCP proxy for handling the acknowledgement of TCP segments and TCP timer handling (e.g., persist timer and keepalive timer) when there happens the disconnection between the moving proxy and the RSU. Thus, it is shown that our TOMS outperforms the legacy TCP in vehicular networks. Index Terms—Vehicular Networks, Vehicular TCP, Coopera- tive TCP, IPv6, VANET I. I NTRODUCTION As one of the most active research areas these days, the advanced vehicular ad hoc networks (VANETs) [1]–[5] can be used for data exchange in road networks where vehicles as moving networks (MNs) with multiple in-vehicle devices or hosts are inter-connected. Some of these services will want to be connected to the Internet. The vehicles are possible to connection to the Internet through Road-Side Units (RSUs). During car driving, you can enjoy the Internet services only under the communication the coverage of RSUs. Such a fundamental vehicular communication framework is referred to as the Drive-thru Internet [4][6]. By this characteristic, Vehicles and the Internet, which are two most prominent elements of our modern lives, has become ever more important [7]. Moreover, for the support of the VANET in road networks, the dedicated short-range communi- cations (DSRC) has been standardized as IEEE 802.11p (now incorporated into IEEE 802.11-2012), which is an extension of IEEE 802.11a, considering the characteristics of vehicular networks, such as high-speed mobility and network fragmen- tation. For wireless access in vehicular environments (WAVE), the IEEE has standardized IEEE 1609 family standards, such as IEEE 1609.3 and 1609.4. The IEEE 1609 standards specify IPv6 as the network-layer protocol. With this trend, it is time to enable vehicular networking with IPv6 to let various Internet- based applications run on top of transport-layer protocols, such as TCP, UDP, and SCTP. IPv6 is suitable for a network layer in vehicular networks in that the protocol has abundant address space, autoconfiguration features, and protocol extension abil- ity through extension headers. Compared with the original wireless local area network (WLAN) scenarios, VANET is a much more challenging task [8] due to the high vehicle mobility, but it has much more predictable information. As reported in [4], the overall connectivity range of an RSU is around 500–600 m, which allows a connection time of 15–18 s to a vehicle moving at the velocity of 120 km/h. In reality, the number of RSUs deployed along the road cannot be enough for providing the ubiquitous coverage due to the high deployment and maintenance cost, particularly in a sparse populated region. Thus, cooperative intervehicle communications is required accordingly as a supplement to extend the coverage of RSUs in vehicular networks. For the fast and reliable data exchange in the vehicular networks, geographically adjacent should be collaborators, not channel competitors of all vehicles [9]. To the best of our knowledge, this paper is the first of TCP-proxy-based data send through TCP Context Migration Scheme (called TOMS). Vehicles can their TCP segments in a delay-tolerant way by using another vehicle close to the communication rage of an RSU as a proxy. Our TOMS allows vehicles to perform proactive TCP connection initialization by 2017 31st International Conference on Advanced Information Networking and Applications Workshops 978-1-5090-6231-7/17 $31.00 © 2017 IEEE DOI 10.1109/WAINA.2017.109 360