Showing papers on "Wireless ad hoc network published in 1999"
TL;DR: Routing protocols for ad hoc networks are examined by providing an overview of eight different protocols by presenting their characteristics and functionality, and then a comparison and discussion of their respective merits and drawbacks are provided.
Abstract: An ad hoc mobile network is a collection of mobile nodes that are dynamically and arbitrarily located in such a manner that the interconnections between nodes are capable of changing on a continual basis. In order to facilitate communication within the network, a routing protocol is used to discover routes between nodes. The primary goal of such an ad hoc network routing protocol is correct and efficient route establishment between a pair of nodes so that messages may be delivered in a timely manner. Route construction should be done with a minimum of overhead and bandwidth consumption. This article examines routing protocols for ad hoc networks and evaluates these protocols based on a given set of parameters. The article provides an overview of eight different protocols by presenting their characteristics and functionality, and then provides a comparison and discussion of their respective merits and drawbacks.
4,278 citations
01 Aug 1999
TL;DR: This paper proposes several schemes to reduce redundant rebroadcasts and differentiate timing of rebroadcast to alleviate the broadcast storm problem, which is identified by showing how serious it is through analyses and simulations.
Abstract: Broadcasting is a common operation in a network to resolve many issues. In a mobile ad hoc network (MANET) in particular, due to host mobility, such operations are expected to be executed more frequently (such as finding a route to a particular host, paging a particular host, and sending an alarm signal). Because radio signals are likely to overlap with others in a geographical area, a straightforward broadcasting by flooding is usually very costly and will result in serious redundancy, contention, and collision, to which we call the broadcast storm problem. In this paper, we identify this problem by showing how serious it is through analyses and simulations. We propose several schemes to reduce redundant rebroadcasts and differentiate timing of rebroadcasts to alleviate this problem. Simulation results are presented, which show different levels of improvement over the basic flooding approach.
3,819 citations
TL;DR: This article takes advantage of the inherent redundancy in ad hoc networks-multiple routes between nodes-to defend routing against denial-of-service attacks and uses replication and new cryptographic schemes to build a highly secure and highly available key management service, which terms the core of this security framework.
Abstract: Ad hoc networks are a new wireless networking paradigm for mobile hosts. Unlike traditional mobile wireless networks, ad hoc networks do not rely on any fixed infrastructure. Instead, hosts rely on each other to keep the network connected. Military tactical and other security-sensitive operations are still the main applications of ad hoc networks, although there is a trend to adopt ad hoc networks for commercial uses due to their unique properties. One main challenge in the design of these networks is their vulnerability to security attacks. In this article, we study the threats on ad hoc network faces and the security goals to be achieved. We identify the new challenges and opportunities posed by this new networking environment and explore new approaches to secure its communication. In particular, we take advantage of the inherent redundancy in ad hoc networks-multiple routes between nodes-to defend routing against denial-of-service attacks. We also use replication and new cryptographic schemes, such as threshold cryptography, to build a highly secure and highly available key management service, which terms the core of our security framework.
2,661 citations
01 Aug 1999
TL;DR: It is found that the SPIN protocols can deliver 60% more data for a given amount of energy than conventional approaches, and that, in terms of dissemination rate and energy usage, the SPlN protocols perform close to the theoretical optimum.
Abstract: In this paper, we present a family of adaptive protocols, called SPIN (Sensor Protocols for Information via Negotiation), that efficiently disseminates information among sensors in an energy-constrained wireless sensor network. Nodes running a SPIN communication protocol name their data using high-level data descriptors, called meta-data. They use meta-data negotiations to eliminate the transmission of redundant data throughout the network. In addition, SPIN nodes can base their communication decisions both upon application-specific knowledge of the data and upon knowledge of the resources that are available to them. This allows the sensors to efficiently distribute data given a limited energy supply. We simulate and analyze the performance of two specific SPIN protocols, comparing them to other possible approaches and a theoretically optimal protocol. We find that the SPIN protocols can deliver 60% more data for a given amount of energy than conventional approaches. We also find that, in terms of dissemination rate and energy usage, the SPlN protocols perform close to the theoretical optimum.
2,525 citations
01 Aug 1999
TL;DR: The first distributed algorithms for routing that do not require duplication of packets or memory at the nodes and yet guarantee that a packet is delivered to its destination are described.
Abstract: We consider routing problems in ad hoc wireless networks modeled as unit graphs in which nodes are points in the plane and two nodes can communicate if the distance between them is less than some fixed unit. We describe the first distributed algorithms for routing that do not require duplication of packets or memory at the nodes and yet guarantee that a packet is delivered to its destination. These algorithms can be extended to yield algorithms for broadcasting and geocasting that do not require packet duplication. A byproduct of our results is a simple distributed protocol for extracting a planar subgraph of a unit graph. We also present simulation results on the performance of our algorithms.
1,537 citations
01 Aug 1999
TL;DR: It is shown that group motion occurs frequently in ad hoc networks, and a novel group mobility model Reference Point Group Mobility (RPGM) is introduced to represent the relationship among mobile hosts.
Abstract: In this paper, we present a survey of various mobility models in both cellular networks and multi-hop networks We show that group motion occurs frequently in ad hoc networks, and introduce a novel group mobility model Reference Point Group Mobility (RPGM) to represent the relationship among mobile hosts RPGM can be readily applied to many existing applications Moreover, by proper choice of parameters, RPGM can be used to model several mobility models which were previously proposed One of the main themes of this paper is to investigate the impact of the mobility model on the performance of a specific network protocol or application To this end, we have applied our RPGM model to two different network protocol scenarios, clustering and routing, and have evaluated network performance under different mobility patterns and for different protocol implementations As expected, the results indicate that different mobility patterns affect the various protocols in different ways In particular, the ranking of routing algorithms is influenced by the choice of mobility pattern
1,503 citations
19 Apr 1999
TL;DR: A resurrecting duckling security policy model is presented, which describes secure transient association of a device with multiple serialised owners over the air in a short range wireless channel.
Abstract: In the near future, many personal electronic devices will be able to communicate with each other over a short range wireless channel. We investigate the principal security issues for such an environment. Our discussion is based on the concrete example of a thermometer that makes its readings available to other nodes over the air. Some lessons learned from this example appear to be quite general to ad-hoc networks, and rather different from what we have come to expect in more conventional systems: denial of service, the goals of authentication, and the problems of naming all need re-examination. We present the resurrecting duckling security policy model, which describes secure transient association of a device with multiple serialised owners.
1,355 citations
01 Jan 1999
TL;DR: It is shown that if n nodes are placed in a disc of unit area in !
Abstract: In wireless data networks each transmitter’s power needs to be high enough to reach the intended receivers, while generating minimum interference on other receivers sharing the same channel. In particular, if the nodes in the network are assumed to cooperate in routing each others’ packets, as is the case in ad hoc wireless networks, each node should transmit with just enough power to guarantee connectivity in the network. Towards this end, we derive the critical power a node in the network needs to transmit in order to ensure that the network is connected with probability one as the number of nodes in the network goes to infinity. It is shown that if n nodes are placed in a disc of unit area in ℜ2 and each node transmits at a power level so as to cover an area of πr 2 = (log n + c(n))/n, then the resulting network is asymptotically connected with probability one if and only if c(n) → +∞.
1,282 citations
01 Aug 1999
TL;DR: In this paper, the authors proposed a simple and efficient distributed algorithm for calculating connected dominating set in ad-hoc wireless networks, where connections of nodes are determined by their geographical distances.
Abstract: Efficient routing among a set of mobile hosts (also called nodes) is one of the most important functions in ad-hoc wireless networks. Routing based on a connected dominating set is a frequently used approach, where the searching space for a route is reduced to nodes in the set. A set is dominating if all the nodes in the system are either in the set or neighbors of nodes in the set. In this paper, we propose a simple and efficient distributed algorithm for calculating connected dominating set in ad-hoc wireless networks, where connections of nodes are determined by their geographical distances. Our simulation results show that the proposed approach outperforms a classical algorithm. Our approach can be potentially used in designing efficient routing algorithms based on a connected dominating set.
1,198 citations
23 Jun 1999
TL;DR: A Distributed Clustered Algorithm (DCA) and a Distributed Mobility-Adaptive Clustering (DMAC) algorithm are presented that partition the nodes of a fully mobile network: (ad hoc network) into clusters, giving the network a hierarchical organization.
Abstract: A Distributed Clustering Algorithm (DCA) and a Distributed Mobility-Adaptive Clustering (DMAC) algorithm are presented that partition the nodes of a fully mobile network: (ad hoc network) into clusters, this giving the network a hierarchical organization. Nodes are grouped by following a new weight-based criterion that allows the choice of the nodes that coordinate the clustering process based on node mobility-rebated parameters. The DCA is suitable for clustering "quasistatic" ad hoc networks. It is easy to implement and its time complexity is proven to be bounded by a network parameter that depends on the topology of the network rather than on its size, i.e., the invariant number of the network nodes. The DMAC algorithm adapts to the changes in the network topology due to the mobility of the nodes, and it is thus suitable for any mobile environment. Both algorithms are executed at each node with the sole knowledge of the identity of the one hop neighbors, and induce on the network the same clustering structure.
1,078 citations
TL;DR: This paper proposes a distributed QoS routing scheme that selects a network path with sufficient resources to satisfy a certain delay (or bandwidth) requirement in a dynamic multihop mobile environment and can tolerate a high degree of information imprecision.
Abstract: In an ad hoc network, all communication is done over wireless media, typically by radio through the air, without the help of wired base stations. Since direct communication is allowed only between adjacent nodes, distant nodes communicate over multiple hops. The quality-of-service (QoS) routing in an ad hoc network is difficult because the network topology may change constantly, and the available state information for routing is inherently imprecise. In this paper, we propose a distributed QoS routing scheme that selects a network path with sufficient resources to satisfy a certain delay (or bandwidth) requirement in a dynamic multihop mobile environment. The proposed algorithms work with imprecise state information. Multiple paths are searched in parallel to find the most qualified one. Fault-tolerance techniques are brought in for the maintenance of the routing paths when the nodes move, join, or leave the network. Our algorithms consider not only the QoS requirement, but also the cost optimality of the routing path to improve the overall network performance. Extensive simulations show that high call admission ratio and low-cost paths are achieved with modest routing overhead. The algorithms can tolerate a high degree of information imprecision.
TL;DR: A large population of mobile stations that are interconnected by a multihop wireless network is considered, with the need to support multimedia communications, with low latency requirements for interactive traffic and quality-of-service (QoS) support for real-time streams (voice/video).
Abstract: We consider a large population of mobile stations that are interconnected by a multihop wireless network. The applications of this wireless infrastructure range from ad hoc networking (e.g., collaborative, distributed computing) to disaster recovery (e.g., fire, flood, earthquake), law enforcement (e.g., crowd control, search-and-rescue), and military (automated battlefield). Key characteristics of this system are the large number of users, their mobility, and the need to operate without the support of a fixed (wired or wireless) infrastructure. The last feature sets this system apart from existing cellular systems and in fact makes its design much more challenging. In this environment, we investigate routing strategies that scale well to large populations and can handle mobility. In addition, we address the need to support multimedia communications, with low latency requirements for interactive traffic and quality-of-service (QoS) support for real-time streams (voice/video). In the wireless routing area, several schemes have already been proposed and implemented (e.g., hierarchical routing, on-demand routing, etc.). We introduce two new schemes-fisheye state routing (FSR) and hierarchical state routing (HSR)-which offer some competitive advantages over the existing schemes. We compare the performance of existing and proposed schemes via simulation.
TL;DR: A novel framework for dynamically organizing mobile nodes in wireless ad hoc networks into clusters in which the probability of path availability can be bounded is presented, which supports an adaptive hybrid routing architecture that can be more responsive and effective when mobility rates are low and more efficient when Mobility rates are high.
Abstract: This paper presents a novel framework for dynamically organizing mobile nodes in wireless ad hoc networks into clusters in which the probability of path availability can be bounded. The purpose of the (/spl alpha/, t) cluster is to help minimize the far-reaching effects of topological changes while balancing the need to support more optimal routing. A mobility model for ad hoc networks is developed and is used to derive expressions for the probability of path availability as a function of time. It is shown how this model provides the basis for dynamically grouping nodes into clusters using an efficient distributed clustering algorithm. Since the criteria for cluster organization depends directly upon path availability, the structure of the cluster topology is adaptive with respect to node mobility. Consequently, this framework supports an adaptive hybrid routing architecture that can be more responsive and effective when mobility rates are low and more efficient when mobility rates are high.
21 Mar 1999
TL;DR: Preliminary performance evaluation shows that CEDAR is a robust and adaptive QoS routing algorithm that reacts effectively to the dynamics of the network while still approximating link-state performance for stable networks.
Abstract: CEDAR is an algorithm for QoS routing in ad hoc network environments. It has three key components: (a) the establishment and maintenance of a self-organizing routing infrastructure called the core for performing route computations, (b) the propagation of the link-state of stable high-bandwidth links in the core through increase/decrease waves, and (c) a QoS route computation algorithm that is executed at the core nodes using only locally available state. But preliminary performance evaluation shows that CEDAR is a robust and adaptive QoS routing algorithm that reacts effectively to the dynamics of the network while still approximating link-state performance for stable networks.
TL;DR: The performance evaluations show that CEDAR is a robust and adaptive QoS routing algorithm that reacts quickly and effectively to the dynamics of the network while still approximating the performance of link-state routing for stable networks.
Abstract: We present CEDAR, a core-extraction distributed ad hoc routing algorithm for quality-of-service (QoS) routing in ad hoc network environments, CEDAR has three key components: (a) the establishment and maintenance of a self-organizing routing infrastructure called the core for performing route computations; (b) the propagation of the link-state of high bandwidth and stable links in the core through increase/decrease waves; and (c) a QoS-route computation algorithm that is executed at the core nodes using only locally available state. The performance evaluations show that CEDAR is a robust and adaptive QoS routing algorithm that reacts quickly and effectively to the dynamics of the network while still approximating the performance of link-state routing for stable networks.
TL;DR: The core-assisted mesh protocol (CAMP) is introduced for multicast routing in ad hoc networks, which generalizes the notion of core-based trees introduced for internet multicasting into multicast meshes that have much richer connectivity than trees.
Abstract: The core-assisted mesh protocol (CAMP) is introduced for multicast routing in ad hoc networks. CAMP generalizes the notion of core-based trees introduced for internet multicasting into multicast meshes that have much richer connectivity than trees. A shared multicast mesh is defined for each multicast group; the main goal of using such meshes is to maintain the connectivity of multicast groups even while network routers move frequently, CAMP consists of the maintenance of multicast meshes and loop-free packet forwarding over such meshes. Within the multicast mesh of a group, packets from any source in the group are forwarded along the reverse shortest path to the source, just as in traditional multicast protocols based on source-based trees. CAMP guarantees that within a finite time, every receiver of a multicast group has a reverse shortest path to each source of the multicast group. Multicast packets for a group are forwarded along the shortest paths front sources to receivers defined within the group's mesh. CAMP uses cores only to limit the traffic needed for a router to join a multicast group; the failure of cores does not stop packet forwarding or the process of maintaining the multicast meshes.
11 Oct 1999
TL;DR: An analytic modeling framework is developed to determine the relative frequency of query floods for various techniques and shows that while multipath routing is significantly better than single path routing, the performance advantage is small beyond a few paths and for long path lengths.
Abstract: Mobile ad hoc networks are characterized by multi-hop wireless links, absence of any cellular infrastructure, and frequent host mobility. Design of efficient routing protocols in such networks is a challenging issue. A class of routing protocols called on-demand protocols has recently attracted attention because of their low routing overhead. The on-demand protocols depend on query floods to discover routes whenever a new route is needed. Such floods take up a substantial portion of network bandwidth. We focus on a particular on-demand protocol, called dynamic source routing, and show how intelligent use of multipath techniques can reduce the frequency of query floods. We develop an analytic modeling framework to determine the relative frequency of query floods for various techniques. Results show that while multipath routing is significantly better than single path routing, the performance advantage is small beyond a few paths and for long path lengths. It also shows that providing all intermediate nodes in the primary (shortest) route with alternative paths has a significantly better performance than providing only the source with alternate paths.
TL;DR: Simulation results show that the location search scheme generates less overhead than the schemes based on flooding, and results confirm that the communication overhead for creating and maintaining the topology in the proposed protocol is smaller than that in the flat LSR protocol.
Abstract: A new global positioning system (GPS)-based routing protocol for ad hoc networks, called zone-based hierarchical link state (ZHLS) routing protocol, is proposed. In this protocol, the network is divided into nonoverlapping zones. Each node only knows the node connectivity within its zone and the zone connectivity of the whole network. The link state routing is performed on two levels: focal node and global zone levels. Unlike other hierarchical protocols, there is no cluster head in this protocol. The zone level topological information is distributed to all nodes. This "peer-to-peer" manner mitigates traffic bottleneck, avoids single point of failure, and simplifies mobility management. Since only zone ID and node ID of a destination are needed for routing, the route from a source to a destination is adaptable to changing topology. The zone ID of the destination is found by sending one location request to every zone. Simulation results show that our location search scheme generates less overhead than the schemes based on flooding. The results also confirm that the communication overhead for creating and maintaining the topology in the proposed protocol is smaller than that in the flat LSR protocol. This new routing protocol provides a flexible, efficient, and effective approach to accommodate the changing topology in a wireless network environment.
TL;DR: This paper presents and studies black-burst (BB) contention, which is a distributed MAC scheme that provides QoS real-time access to ad hoc CSMA wireless networks and provides conditions for the scheme to be stable.
Abstract: Carrier sense multiple access (CSMA) is one of the most pervasive medium access control (MAC) schemes in ad hoc, wireless networks. However, CSMA and its current variants do not provide quality-of-service (QoS) guarantees for real-time traffic support. This paper presents and studies black-burst (BB) contention, which is a distributed MAC scheme that provides QoS real-time access to ad hoc CSMA wireless networks. With this scheme, real-time nodes contend for access to the channel with pulses of energy-so called BBs-the durations of which are a function of the delay incurred by the nodes until the channel became idle. It is shown that real-time packets are not subject to collisions and that they have access priority over data packets. When operated in an ad hoc wireless LAN, BB contention further guarantees bounded and typically very small real-time delays. The performance of the network can approach that attained under ideal time division multiplexing (TDM) via a distributed algorithm that groups real-time packet transmissions into chains. A general analysis of BB contention is given, contemplating several modes of operation. The analysis provides conditions for the scheme to be stable. Its results are complemented with simulations that evaluate the performance of an ad hoc wireless LAN with a mixed population of data and real-time nodes.
21 Sep 1999
TL;DR: It is shown via simulations that this new carrier-sense multiple access (CSMA) protocol provides a higher throughput compared to its single channel counterpart by reducing the packet loss due to collisions and the use of channel reservation provides better performance than multichannel CSMA with purely random idle channel selection.
Abstract: We describe a new carrier-sense multiple access (CSMA) protocol for multihop wireless networks, sometimes also called ad hoc networks. The CSMA protocol divides the available bandwidth into several channels and selects an idle channel randomly for packet transmission. It also employs a notion of "soft" channel reservation as it gives preference to the channel that was used for the last successful transmission. We show via simulations that this multichannel CSMA protocol provides a higher throughput compared to its single channel counterpart by reducing the packet loss due to collisions. We also show that the use of channel reservation provides better performance than multichannel CSMA with purely random idle channel selection.
TL;DR: This paper analyze the use of on-demand behavior in routing protocols, focusing on its effect on the routing protocol's forwarding latency, overhead cost, and route caching correctness, drawing examples from detailed simulation of the dynamic source routing (DSR) protocol.
Abstract: A number of different routing protocols proposed for use in multihop wireless ad hoc networks are based in whole or in part on what can be described as on-demand behavior. By on-demand behavior, we mean approaches based only on reaction to the offered traffic being handled by the routing protocol. In this paper, we analyze the use of on-demand behavior in such protocols, focusing on its effect on the routing protocol's forwarding latency, overhead cost, and route caching correctness, drawing examples from detailed simulation of the dynamic source routing (DSR) protocol. We study the protocol's behavior and the changes introduced by variations on some of the mechanisms that make up the protocol, examining which mechanisms have the greatest impact and exploring the tradeoffs that exist between them.
21 Sep 1999
TL;DR: A novel soft state wireless hierarchical routing protocol-Hierarchical State Routing (HSR) is proposed, which keeps track of logical subnet movements using home agent concepts akin to Mobile IP.
Abstract: In this paper we present a hierarchical routing protocol in a large wireless, mobile network such as found in the automated battlefield or in extensive disaster recovery operations. Conventional routing does not scale well to network size. Likewise, conventional hierarchical routing cannot handle mobility efficiently. We propose a novel soft state wireless hierarchical routing protocol-Hierarchical State Routing (HSR). We distinguish between the "physical" routing hierarchy (dictated by geographical relationships between nodes) and "logical" hierarchy of subnets in which the members move as a group (e.g., company, brigade, battalion in the battlefield). HSR keeps track of logical subnet movements using home agent concepts akin to Mobile IP. A group mobility model is introduced and the performance of the HSR is evaluated through a detailed wireless simulation model.
31 Oct 1999
TL;DR: This paper introduces AMRIS, a new multicast routing protocol for ad hoc wireless networks designed to operate independently of underlying unicast protocols and the results reported are simulated with PARSEC.
Abstract: This paper introduces AMRIS, a new multicast routing protocol for ad hoc wireless networks. AMRIS (Ad hoc Multicast Routing protocol utilizing Increasing id-numberS) is designed to operate independently of underlying unicast protocols. The idea behind AMRIS is to dynamically assign every node (on demand) in a multicast session with an id-number. The ordering between id-numbers is used to direct the multicast flow, and the sparseness among them used for quick connectivity repair. A multicast delivery tree rooted at a special node called Sid joins up the nodes participating in the multicast session. The relationship between the id-numbers (and the nodes that own them) and Sid is that the id-numbers increase in numerical value as they radiate from Sid in the delivery tree. These id-numbers help the nodes dynamically leave and join a session, as well as adapt rapidly to changes in link connectivity (due to mobility etc.). Messages to repair a link breakage are confined to the region where it occurs. AMRIS is simulated with PARSEC and the results reported.
16 May 1999
TL;DR: In this paper, the problem of transmit beamforming is formulated as one of minimizing the power radiated by the base station, subject to satisfying quality of service requirements at the mobiles, and an iterative algorithm that converges to it is provided.
Abstract: Transmit beamforming is a powerful means of increasing capacity in systems in which the transmitter is equipped with an antenna array, especially in systems in which receive beamforming is not available, as is typical in the base-to-mobile downlink in a cellular communication system. In this paper, the problem of transmit beamforming is formulated as one of minimizing the power radiated by the base station, subject to satisfying quality of service requirements at the mobiles. For a single cell system, a global minimum is shown to exist, and an iterative algorithm that converges to it is provided. The solution extends to accommodate receive beamforming at the mobiles. It also extends to provide a mechanism for space-time transmit filtering, which exploits the differences between the temporal as well as the spatial channels between the base station and different mobiles. Finally, a system with multiple source-destination pairs (e.g., in an ad hoc network) is considered. An iterative algorithm that outputs a convergent sequence of feasible points with monotonically decreasing costs is provided for this case.
01 Aug 1999
TL;DR: It is demonstrated that even flooding is insufficient for reliable multicast in ad hoc networks when mobility is very high, and traditional multicast approaches are not appropriate.
Abstract: Ad hoc networks are gaining popularity as a result of advances in smaller, more versatile and powerful mobile computing devices. The distinguishing feature of these networks is the universal mobility of all hosts. This requires re-engineering of basic network services including reliable multicast communication. This paper considers the special case of highly mobile fast-moving ad hoc networks and argues that, for such networks, traditional multicast approaches are not appropriate. Flooding is suggested as a possible alternative for reliable multicast and simulation results are used to illustrate its effects. The experimental results also demonstrate a rather interesting outcome that even flooding is insufficient for reliable multicast in ad hoc networks when mobility is very high. Some alternative, more persistent variations of flooding are sketched out.
TL;DR: The average cost, due to call loss and location updates using such systems, is analyzed in the presence of database disconnections and the tradeoff between the system reliability and the cost of location updates in the UQS scheme is investigated.
Abstract: A distributed mobility management scheme using a class of uniform quorum systems (UQS) is proposed for ad hoc networks. In the proposed scheme, location databases are stored in the network nodes themselves, which form a self-organizing virtual backbone within the flat network structure. The databases are dynamically organized into quorums, every two of which intersect at a constant number of databases. Upon location update or call arrival, a mobile's location information is written to or read from all the databases of a quorum, chosen in a nondeterministic manner. Compared with a conventional scheme [such as the use of home location register (HLR)] with fixed associations, this scheme is more suitable for ad hoc networks, where the connectivity of the nodes with the rest of the network can be intermittent and sporadic and the databases are relatively unstable. We introduce UQS, where the size of the quorum intersection is a design parameter that can be tuned to adapt to the traffic and mobility patterns of the network nodes. We propose the construction of UQS through the balanced incomplete block designs. The average cost, due to call loss and location updates using such systems, is analyzed in the presence of database disconnections. Based on the average cost, we investigate the tradeoff between the system reliability and the cost of location updates in the UQS scheme. The problem of optimizing the quorum size under different network traffic and mobility patterns is treated numerically. A dynamic and distributed HLR scheme, as a limiting case of the UQS, is also analyzed and shown to be suboptimal in general. It is also shown that partitioning of the network is sometimes necessary to reduce the cost of mobility management.
21 Sep 1999
TL;DR: MCEDAR is an extension to the CEDAR architecture and provides the robustness of mesh based routing protocols and the efficiency of tree based forwarding protocols and it decouples the control infrastructure from the actual data forwarding infrastructure.
Abstract: In this paper, we present the MCEDAR (multicast core extraction distributed ad hoc routing) multicast routing algorithm for ad hoc networks. MCEDAR is an extension to the CEDAR architecture and provides the robustness of mesh based routing protocols and the approximates the efficiency of tree based forwarding protocols. It decouples the control infrastructure from the actual data forwarding infrastructure. The decoupling allows for a very minimalistic and low overhead control infrastructure while still enabling very efficient data forwarding.
TL;DR: The ad hoc network management protocol (ANMP) is fully compatible with simple management protocol, version 3 (SNMPv3) and uses the same protocol data units (PDUs) for data collection and implements sophisticated security mechanisms that can be fine-tuned to meet specific requirements.
Abstract: We present a protocol for managing mobile wireless ad hoc networks. The protocol uses hierarchical clustering of nodes to reduce the number of messages exchanged between the manager and the agents (mobiles). Clustering also enables the network to keep track of mobiles as they roam. The ad hoc network management protocol (ANMP) is fully compatible with simple management protocol, version 3 (SNMPv3) and uses the same protocol data units (PDUs) for data collection. The protocol also implements sophisticated security mechanisms that can be fine-tuned to meet specific requirements. Finally, we have implemented the protocol along with a graphical user interface that allows a manager to change the view or specify management parameters on the fly.
23 Jun 1999
TL;DR: A technique is described that allows a single ad hoc network to span across heterogeneous link layers, which can both integrate ad hoc networks into the hierarchical Internet and support the migration of mobile nodes from the Internet into and out of ad hoc Networks via Mobile IP.
Abstract: Much progress has been made toward solving the problem of routing packets inside an ad hoc network, but there are presently no complete proposals for connecting ad hoc networks together to form larger networks, or for integrating them with wired Internets. We describe a technique that allows a single ad hoc network to span across heterogeneous link layers. Using this technique, we can both integrate ad hoc networks into the hierarchical Internet and support the migration of mobile nodes from the Internet into and out of ad hoc networks via Mobile IP. Taken together, these solutions improve the scalability of flat ad hoc networks by introducing hierarchy, and they enable all nodes participating in the ad hoc network to be reachable from anywhere in the world. We have implemented each of the solutions in a real testbed of 8 nodes using the Dynamic Source Routing (DSR) protocol. Generalizing our solutions, we describe several abstract scenarios and present our ideas for solving them.
21 Sep 1999
TL;DR: A novel routing metric is proposed, which defines a probabilistic measure of the availability of network paths that are subject to link failures caused by node mobility in ad-hoc networks, and it is shown how this measure can be used to select more stable paths and reduce the routing overhead caused by nodes mobility.
Abstract: Ad-hoc networks are expected to play an important role in future commercial and military communications systems. As such, scalable routing strategies capable of supporting greater user mobility and a wide range of applications are needed. This paper proposes a novel routing metric, which defines a probabilistic measure of the availability of network paths that are subject to link failures caused by node mobility in ad-hoc networks. It is shown how this measure can be used to select more stable paths and reduce the routing overhead caused by node mobility. A mobility model is first proposed and used to characterize the movement of ad-hoc network nodes. This model is then used to derive expressions for link and path availability. Finally, simulation results are reported which validate the proposed analytical model.