Reverse DNS (rDNS) names often contain information not only about core routers in some networks but about hosts on edge networks. Although the rDNS names of routers have been decoded and their naming patterns verified by researchers, the information extracted from edge host rDNS names has been limited to intuitive keywords. In this paper, we develop a methodology for identifying and analyzing rDNS names for broadband Internet end hosts without using any pre-defined keyword. With this methodology, we study whether ISPs use intuitive keywords in their rDNS names and whether rDNS names embed correct information (e.g., whether keyword "cable" indicates cable clients but not fiber or DSL clients).

There are several mechanisms by which users can gain insight into where their packets have gone, but no mechanisms allow users undeniable proof that their packets did not traverse certain parts of the world while on their way to or from another host. This paper introduces the problem of finding "proofs of avoidance": evidence that the paths taken by a packet and its response avoided a user-specified set of "forbidden" geographic regions. Proving that something did not happen is often intractable, but we demonstrate a low-overhead proof structure built around the idea of what we call "alibis": relays with particular timing constraints that, when upheld, would make it impossible to traverse both the relay and the forbidden regions.

Flooding, that is to deliver a packet from one node to all other nodes in the network, is an integral part of many wireless protocols. Flooding is often implemented by a series of broadcasts of each node and this causes some problems such as the broadcast storm and low reliability, by being engaged with the effects of radio signal propagation, e.g., multipath fading and interference. Many researchers have studied these problems over the years, however, most of these studies have been carried out assuming that all nodes in the network are equipped with a single radio interface and utilize only a single channel. This implies that most of the existing mechanisms that enhance the performance of flooding in wireless networks will not work in multi-radio multi-channel wireless mesh networks (MR-MC WMNs). Motivated by this, in this paper, we propose a flooding mechanism that works well in MR-MC WMNs. Our flooding mechanism, which can operate with an arbitrary number of radio interfaces and channels, increases the reliability of flooding while alleviates the broadcast storm problem, using only local information. Through a detailed simulation study, we demonstrate that our flooding mechanism improves both the reliability and the efficiency of flooding in MR-MC WMNs.

Flooding is a mechanism that distributes packets to every node of the network. The flooding mechanism is frequently used in many operations in wireless multi-hop networks. Since flooding exploits hop-by-hop broadcasting that suffers from unreliable transmission and fading, it is hard to achieve the reliability in flooding. As unreliable flooding may lead to a coverage hole, it will have a negative effect upon upper layer protocols. In this paper, we introduce a Reliability Aware Flooding Algorithm (RAFA), which estimates the expected reliability using two-hop topology knowledge. The estimated reliability is used for deciding whether or not to retransmit a packet. Using NS-2 [19] simulator, we show that RAFA achieves the higher reliability than RBP [1] by adjusting the number of retransmissions considering the network topology, regardless of the network topologies, the node density or the number of bottlenecks.

Finding a reliable and efficient routing path in vehicular ad hoc networks (VANETs) is a challenging issue due to high mobility of vehicles and frequent link breakage. Motivated by this, we propose a robust and efficient routing protocol, called MMR. The contribution of this paper is two-fold: two-level routing and a new routing metric. A routing process of MMR consists of the macro level and the micro level. MMR forwards a packet to an approximate location of the destination at the macro level and then forwards a packet to the exact location of the destination at the micro level. This two-level routing reduces the protocol overhead and improves scalability in terms of the number of nodes. MMR also introduces a new routing metric that reduces the protocol overhead and path breakage by considering velocities of vehicles. Through simulations, we show that MMR improves the routing performance by about 30~40% in highly mobile environments, compared to the existing ad hoc routing protocols such as AODV and GPSR.

In vehicular ad hoc networks (VANETs), geographic routing protocols appear to be a fascinating option since they have generally low delay and small routing overhead and GPS devices are becoming affordable. However, we reveal that geographic routing protocols suffer from routing holes when nodes are distributed only on lines such as cars on roads, trains on rails, and ships on courses. To tackle this problem, we propose a novel geographic routing protocol, virtual vertex routing (VVR), which uses the information of the lines. Using graph formulation, we introduce a new concept, the proximity of a vertex (or a virtual vertex). An intermediate node in this proximity performs routing toward the destination by Floyd algorithm. For routing holes, we propose two countermeasures: greedy routing (VVR-GR) and face routing (VVR-FR). The latter can guarantee the packet delivery. Extensive simulations are performed to show that VVR outperforms GPSR and AODV.