## 3 NDN Enabled Communication and Transport Research in V2X
### Dynamic Forwarding
An alternative suggestion for that scenario would be to estimate whether vehicle D will leave the communication range and, therefore, prepare Interests that register the corresponding PIT entry in vehicle E.  
Another convenient feature of NDN is the field _ForwardingHint_ (cf. Figure 1). This Interest packet field enables to store information about where the Interest may be forwarded. This can ease forwarding  
Figure 4: The problem of _unsolicited_ Data packets in medium to high velocity V2X scenarios decreasing delivery ratio and increasing delay. (**a**) Vehicle A requests content that is located at vehicle C. The red arrows illustrate the Interests flow which are forwarded via vehicle D and B to C. We assume that the other vehicles are out of range. So, the only available path is the one shown by red arrows. (**b**) Vehicle C returns the Data packet(s), but vehicle D is already out of range and vehicle E may receive the Data packet(s) (vehicle E replaces D w.r.t. to the corresponding Face). In both cases the Data packet(s) are discarded (once because D moved out of range, and once because for E the received Data packet(s) are unsolicited). if the forwarding strategy already discovered paths for Interests with the same prefix (of course this may underlie some constraints). Utilization of the ForawrdingHint potentially decreases the effort of searching new paths at intermediate nodes, similar to dynamic source routing in mobile ad-hoc networks for IPv4 [22]. However, forwarding strategies do not utilize this feature which may become relevant in V2X communication, because the pre-coding of a path may proof to become useful for certain applications. The assumption of _available routing information_ is a further point of interest regarding forwarding strategies. Many of the listed forwarding strategies rely on a priori routing information or even rely on the knowledge of the overall topology or global vehicle information. This means that they are not able to discover new paths by themselves leading to the fact that they are not suitable for building the foundation of ad-hoc V2X communication. A further issue in dynamic forwarding is _Interest flooding_ of V2X forwarding strategies. On the one hand, this increases the satisfaction ratio, but on the other hand, Interest flooding can quickly escalate to broadcast storms preventing other network traffic, such as traffic information updates, from being properly delivered. In highly changing environments such as V2X scenarios, forwarding strategies must be able to react and find/reveal new paths within a short amount of time. However, development of V-NDN has introduced mechanisms which overtake some of the functionalities of a forwarding strategy (in V-NDN first the FIB was removed and broadcasting of Interests was implemented, later the FIB was re-introduced). We think the architecture of NDN should not vary depending its area of application and its applicability should be seamless. Since NDN allows to use different forwarding strategies for different prefixes, we think that it is the duty of forwarding strategies to find new paths and to maximize or minimize certain metrics (i.e., satisfaction ratio, delay) in V2X scenarios.