Showing papers on "Wireless Routing Protocol published in 1993"

RSVP: a new resource ReSerVation Protocol

Abstract: A resource reservation protocol (RSVP), a flexible and scalable receiver-oriented simplex protocol, is described. RSVP provides receiver-initiated reservations to accommodate heterogeneity among receivers as well as dynamic membership changes; separates the filters from the reservation, thus allowing channel changing behavior; supports a dynamic and robust multipoint-to-multipoint communication model by taking a soft-state approach in maintaining resource reservations; and decouples the reservation and routing functions. A simple network configuration with five hosts connected by seven point-to-point links and three switches is presented to illustrate how RSVP works. Related work and unresolved issues are discussed. >

A survey of wormhole routing techniques in direct networks

Abstract: Several research contributions and commercial ventures related to wormhole routing, a switching technique used in direct networks, are discussed. The properties of direct networks are reviewed, and the operation and characteristics of wormhole routing are discussed in detail. By its nature, wormhole routing is particularly susceptible to deadlock situations, in which two or more packets may block one another indefinitely. Several approaches to deadlock-free. routing, along with a technique that allows multiple virtual channels to share the same physical channel, are described. In addition, several open issues related to wormhole routing are discussed. >

System for extending network resources to remote networks

Abstract: A system for interconnecting networks transparently extends the multiprotocol routing functionality of a router across a communication link to a remote LAN, while requiring a device on the remote LAN which operates independent of the higher layer protocol suites. A boundary router, having a local routing interface coupled to the first network, and a remote routing interface coupled to the communication link, provides the higher level protocol suite services for routing frames of data to terminals in the first and second networks. A routing adapter extends the remote routing interface of the boundary router transparently across the communication link to the second network.

A comparison of adaptive wormhole routing algorithms

Abstract: Improvement of message latency and network utilization in torus interconnection networks by increasing adaptivity in wormhole routing algorithms is studied. A recently proposed partially adaptive algorithm and four new fully-adaptive routing algorithms are compared with the well-known e-cube algorithm for uniform, hotspot, and local traffic patterns. Our simulations indicate that the partially adaptive north-last algorithm, which causes unbalanced traffic in the network, performs worse than the nonadaptive e-cube routing algorithm for all three traffic patterns. Another result of our study is that the performance does not necessarily improve with full-adaptivity. In particular, a commonly discussed fully-adaptive routing algorithm, which uses 2n virtual channels per physical channel of a k-ary n-cube, performs worse than e-cube for uniform and hotspot traffic patterns. The other three fully-adaptive algorithms, which give priority to messages based on distances traveled, perform much better than the e-cube and partially-adaptive algorithms for all three traffic patterns. One of the conclusions of this study is that adaptivity, full or partial, is not necessarily a benefit in wormhole routing.

The Message Flow Model for Routing in Wormhole-Routed Networks

Abstract: In this paper, we introduce a new approach to deadlock-free routing in wormhole-routed networks called the message flow model. We first establish the necessary and sufficient condition for deadlock-free routing based on the analysis of the message flow on each channel. We then show how to use the model to prove that a given adaptive routing algorithm is deadlock-free. Finally, we use the method to de? velop new, efficient adaptive routing algorithms for 2D meshes and hypercubes.

Adaptive Deadlock-Free Routing in Multicomputers Using Only One Extra Virtual Channel

Abstract: We present three protocols defin ing the relationship between messages and the chan nel resources requested: request-then-hold, requestthen wait, and request-then-relinquish. Based on the three protocols, we develop an adaptive deadlockfree routing algorithm called the SP routing. The SP routing uses shortest paths and is fully-adaptive, so messages can be routed via any of the shortest paths from the source to the destination. Since it is a minimal or shortest routing, the SP routing guar antees the freedom of livelocks. The SP routing is not limited to a specific network topology. The main requirement for an applicable network topology is that there exists a deterministic, minimal, deadlock-free routing algorithm. Most ex isting network topologies are equipped with such an algorithm. In this paper, we present an adaptive deadlock-free routing agorithm for n-dimensional meshes by using the SP routing. The hardware re quired by the SP routing uses only one extra virtual channel as compared to the deterministic routing.

Routing multipoint connections using virtual paths in an ATM network

Abstract: The point-to-multipoint routing problem is studied for an asynchronous transfer mode (ATM) network that uses virtual paths (VPs). ATM networks with asymmetric and symmetric VPs are considered, and the performance factors studied are bandwidth and establishment and switching costs. A VP with intermediate exit, where a node that performs VP switching can copy the switched packets for the local destination, is proposed and studied. Mathematical formulations of multicast routing problems are presented, and heuristics for finding a low cost multicast routing tree, based on the transshipment simplex algorithm, are developed. >

An Efficient Timing-Driven Global Routing Algorithm

Abstract: In this paper, we propose an efficient timing-driven global routing algorithm. Unlike other conventional global routing techniques, interconnection delays are modeled and included during routing and rerouting process in order to minimize the routing area as well as to satisfy timing constraint. The timing-driven global routing problem is formulated as a multiterminal, multicommodity flow problem with integer flows and additional timing constraint. Two efficient timing-driven Steiner tree approach and one Steiner tree improving approach have been used to create initial routing results and reroute trees respectively. The algorithm has been implemented and the experimental results are quite promising.

Dynamics of internet routing information

Abstract: The Internet is a complex mesh of networks that use a common suite (TCP/IP) of networking protocols. A key feature of the Internet is that all of these constituent networks are interconnected, thereby providing system wide communication. The magnitude and pattern of the flow of routing information directly represents the connectivity stability of the Internet. The NSFNET backbone network provides transit services to a large portion of the global Internet and maintains routing tables reflecting this current connectivity. These routing tables are constantly updated based on information received by the attached networks. This paper investigates the dynamics of routing information flow as presented to the NSFNET backbone network.

Inter-Domain Policy Routing Protocol Specification: Version 1

Abstract: We present the set of protocols and procedures that constitute Inter-Domain Policy Routing (IDPR). IDPR includes the virtual gateway protocol, the flooding protocol, the route server query protocol, the route generation procedure, the path control protocol, and the data message forwarding procedure.

Unslotted deflection routing in all-optical networks

Abstract: When nodes of a communication network have identical input- and output-link capacities, it is possible to use as few as one packet buffer per link, if one is willing to deflect-or misroute-a subset of simultaneously arriving fixed-length packets from preferred to alternate output links. This scheme, known as deflection routing, can achieve very fast packet switching in regular networks and has been proposed as the basic routing and switching protocol of several all-optical networks. The performance models of deflection-routing networks that have appeared in the literature have assumed that time is slotted and packets arrive at nodes on time-slot boundaries. In practice, however, slotted operation is difficult to implement in all-optical networks. The present authors evaluate by simulation the performance of deflection routing in unslotted networks. The evaluations show a surprising degradation of throughput in unslotted deflection routing networks, compared to slotted networks, and reveal situations where severe congestion occurs. To overcome these limitations they propose the use of specific control mechanisms in unslotted networks that allow one to eliminate congestion and to improve substantially the network throughput. >

A new theory of deadlock-free adaptive multicast routing in wormhole networks

Abstract: A theory for the design of deadlock-free adaptive routing algorithms for wormhole networks has been proposed previously. This theory supplies the sufficient conditions for an adaptive routing algorithm to be deadlock-free, even when there are cyclic dependencies between channels. Also, two design methodologies have been proposed. Multicast communication refers to the delivery of the same message from one source node to an arbitrary number of destination nodes. Two multicast wormhole routing methods have been presented previously for multicomputers with 2D-mesh and hypercube topologies. This paper develops the theoretical background for the design of deadlock-free adaptive multicast routing algorithms for wormhole networks. Some basic definitions and two theorems are proposed, developing conditions to verify that an adaptive multicast routing algorithm is deadlock-free, even when there are cyclic dependencies between channels. As an example, the multicast routing algorithms presented previously are extended, so that they can take advantage of the alternative paths offered by the network. >

Integrating security in inter-domain routing protocols

Abstract: Network routing protocols work in a vulnerable environment. Unless protected by appropriate security measures, their operation can be easily subverted by intruders capable of modifying, deleting or adding false information in routing updates. This paper first analyses threats to the secure operation of inter-domain routing protocols, and then proposes various counter measures to make these protocols secure against external threats.

Deadlock-free fault-tolerant routing in injured hypercubes

Abstract: Wormhole routing with the e-cube algorithm is an excellent solution for deadlock-free interprocess communication in healthy hypercubes. However, it does not work for injured hypercubes where some nodes and/or links are faulty. The authors propose a new deadlock-free routing scheme in an injured hypercube with the wormhole routing capability. All previously proposed schemes suggest the use of virtual channels to avoid the cycle of resource dependency. By contrast, the authors' scheme is based on the re-establishment of a routing path to the destination, but it does not always yield a shortest path between the source and destination. The proposed routing scheme uses either wormhole routing or staged routing, depending on the availability of one or more healthy (n-2)-cubes within an injured n-cube. >

Dispersity routing on ATM networks

Abstract: Dispersity routing is defined. It is combined with random access and fast circuit set-up and tear-down to put bursty data on an asynchronous transfer mode (ATM) network. This approach makes the storage in the network independent of the message length. This approach is evaluated assuming that the propagation delay may be more than the message transmission time. It is shown that the efficiency improves as the number of channels on each path increases, and that dispersity routing makes it reasonable to use the strategy on networks with a small number of channels per path. Dispersity routing requires networks with multiple paths between many of the nodes. This characteristic is also required for many adaptive routing strategies. A class of networks is proposed in which the fraction of nodes with multiple paths, and the number of multiple paths between nodes, can be controlled. These networks provide a platform for evaluating multiple path strategies. >

Dynamic routing in multiparented networks

Abstract: The authors investigate some of the consequences for dynamic routing schemes of dual- and multiparented networks, in which a call can enter (or leave) the network at two or more points. In particular, they compare bounds on the performance of optimal dynamic routing strategies which respectively ignore and utilize the multiparented structure, and show that simple schemes, easily implemented and analyzed, are able to achieve most of the additional advantages allowed to dynamic routing schemes by multiparenting. The robust behavior of these schemes under traffic mismatches as well as multiple link or node failure events is illustrated. >

A protocol for route establishment and packet forwarding across multidomain internets

Abstract: Internetworks that are global in scale, contain multiple administrative domains, and support a range of services present special requirements for routing. Multiple administrative domains introduce the need for policy-sensitive routing. Service heterogeneity intensifies the requirement for type of service (TOS) routing, as well as other protocol support for handling a range of services, from datagrams to multimedia streams. Key concepts and protocols developed as part of the interdomain policy routing (IDPR) architecture are summarized. Emphasis is placed on the route installation and packet forwarding mechanisms because they are critical to protocol performance and differ significantly from current practice in datagram wide area networks. >

Routing in High-Speed Networks

Abstract: In the 1990''s, significant advances in fiber optic and switching technology have precipitated the current explosion in the amount of research in future high-speed networks The challenges facing high-speed network researchers result not just from the high data transmission rate but also from other new charactoristics not previously encountered in traditional circuit-switched or packet-switched networks For example, features such as large propagation delay as compared to transmission delay; diverse application demands, constraints on all call processing capacity, and quality-of service QOS support for differant application all present new challenges which arise from the new technology and new applications Thus, much reseach is needed not just to improve existing technologies, but to seek a fundamentally differant approach toward network architectures and protocols In particular, new flow flow control and routing algorithms need to be developed to meet these new challenges The goal of this dissertation is to solve routing problems in the context of high-speed networks taking into account the new network environment In order to better undwerstand the influence of these new network characteristics on the routing problem, we first study the computational delays associated with call admission,routing, and call setup in the future of high-speed networks This study also leads us to explore the similarity between call setup in high-speed networks and circuit-switched networks and to study how approaches toward routing in circuit-switched networks can be adapted for routing in high-speed networks Specifically, based on the Markov Decision Process (MDP) framework, we next design and evaluate state-dependent routing algorithms for high-speed networks which account for the these new network characteristics Finally we consider the Virtual Path (VP) concept that has been proposed to simplify traffic control and resource management in future high-speed networks Thus, in the last part of this dissertation, we also demonstrate the efficiency of MDP-based routing algorithms in virtual path-based networks

A Class of Partially Adaptive Routing Algorithms for n_dimensional Meshes

Abstract: A simple model, called the direction restriction model, for developing partially adaptive routing algorithms for n_dimensional meshes is introduced in this paper. This model is based on dividing a system into two unidirectional networks that contain all physical channels of the system.

Dimensioning of adaptively routed networks

Abstract: The authors present an algorithm for the multihour dimensioning of telephone networks operating with residual capacity adaptive routing. The method is based on dimensioning techniques for networks operating with nonhierarchical alternate routing and relies on a conservative approximation for traffic evaluation. It is a decomposition method involving a set of fixed-point equations which are solved iteratively until the Kuhn-Tucker conditions are met. The authors investigate the convergence of the method and find that some of the variables of the model are almost stationary after only a few iterations. This leads to some simplifications that make it suitable for large networks with minor modifications. They also investigate the optimality of adaptive routing by comparing it with the optimal routing coefficients and verify the operation of this routing in a network dimensioned for adaptive technique. A question of interest is how well an adaptive algorithm can adapt to dimensioning errors and how well it compares with the optimal routing in these situations. >

Stability of a class of dynamic routing protocols (IGRP)

Abstract: An exact analysis of the dynamic behavior of IGRP, an adaptive shortest-path routing algorithm, is performed. The distance metric is a weighted sum of traffic-sensitive and traffic-insensitive delay components. The optimality and stability of the protocol is related to the ratio of the weights. In particular, it is shown that if the traffic-sensitive component is not given enough weight, then starting from any initial routing, the subsequent routings after finitely many update periods will oscillate between two worst cases. Otherwise, the successive routings will converge to the unique equilibrium routing. It is also shown that load sharing among routes whose distances are within a threshold of the minimum distance helps stabilize the dynamic behavior. >

CSMA/CD protocol for time-constrained communication on bus networks

Abstract: A multiple access protocol for transmitting time-constrained packets on bus networks is presented. Based on carrier sense multiple access/ collision detection (CSMA/CD) protocol, a new protocol is developed and its performance evaluated by computer simulation. An approximate analysis model for this protocol is also presented. Numerical results indicate that the new protocol achieves a better performance, and the approximate analysis model is also effective.

Rule-based call-by-call source routing for integrated communication networks

Abstract: Routing subject to multiple quality-of-service (QOS) constraints is considered. Such a problem arises in both private corporate backbone networks and public switched networks, and will become even more prevalent in the future with the emergence of asynchronous transfer mode (ATM) networks. A rule-based call-by-call source routing strategy that makes use of routing fallbacks to accommodate users with diverse QOS requirements is proposed. >