Showing papers on "Wireless Routing Protocol published in 1995"

Improving reliable transport and handoff performance in cellular wireless networks

Abstract: TCP is a reliable transport protocol tuned to perform well in traditional networks where congestion is the primary cause of packet loss. However, networks with wireless links and mobile hosts incur significant losses due to bit-errors and hand-offs. This environment violates many of the assumptions made by TCP, causing degraded end-to-end performance. In this paper, we describe the additions and modifications to the standard Internet protocol stack (TCP/IP) to improve end-to-end reliable transport performance in mobile environments. The protocol changes are made to network-layer software at the base station and mobile host, and preserve the end-to-end semantics of TCP. One part of the modifications, called the snoop module, caches packets at the base station and performs local retransmissions across the wireless link to alleviate the problems caused by high bit-error rates. The second part is a routing protocol that enables low-latency handoff to occur with negligible data loss. We have implemented this new protocol stack on a wireless testbed. Our experiments show that this system is significantly more robust at dealing with unreliable wireless links than normal TCP; we have achieved throughput speedups of up to 20 times over regular TCP and handoff latencies over 10 times shorter than other mobile routing protocols.

A distributed routing algorithm for mobile wireless networks

Abstract: We present a loop-free, distributed routing protocol for mobile packet radio networks. The protocol is intended for use in networks where the rate of topological change is not so fast as to make “flooding” the only possible routing method, but not so slow as to make one of the existing protocols for a nearly-static topology applicable. The routing algorithm adapts asynchronously in a distributed fashion to arbitrary changes in topology in the absence of global topological knowledge. The protocol's uniqueness stems from its ability to maintain source-initiated, loop-free multipath routing only to desired destinations with minimal overhead in a randomly varying topology. The protocol's performance, measured in terms of end-to-end packet delay and throughput, is compared with that of pure flooding and an alternative algorithm which is well-suited to the high-rate topological change environment envisioned here. For each protocol, emphasis is placed on examining how these performance measures vary as a function of the rate of topological changes, network topology, and message traffic level. The results indicate the new protocol generally outperforms the alternative protocol at all rates of change for heavy traffic conditions, whereas the opposite is true for light traffic. Both protocols significantly outperform flooding for all rates of change except at ultra-high rates where all algorithms collapse. The network topology, whether dense or sparsely connected, is not seen to be a major factor in the relative performance of the algorithms.

A routing protocol for packet radio networks

Abstract: : The authors present a new distance-vector routing protocol for a packet radio network. The new distributed routing protocol, Wireless Routing Protocol (WRP), works on the notion of second-to-last hop node to a destination. WRP reduces the number of cases in which a temporary routing loop can occur and also provides a mechanism for the reliable transmission of update messages. The performance of WRP has been compared quantitatively by simulations with that of distributed Bellman-Ford (DBF), DUAL (a loop-free, distance-vector algorithm), and an ideal link-state algorithm (ILS) that represents the state of the art of Internet routing in a highly dynamic environment. The simulation results indicate that WRP is the most efficient of the algorithms simulated in a wireless environment.

Routing subject to quality of service constraints in integrated communication networks

Abstract: With increasingly diverse QOS requirements, it is impractical to continue to rely on conventional routing paradigms that emphasize the search for an optimal path based on a predetermined metric, or a particular function of multiple metrics. Modern routing strategies must not only be adaptive to network changes but also offer considerable economy of scope. We consider the problem of routing in networks subject to QOS constraints. After providing an overview of prior routing work, we define various QOS constraints. We present a call architecture that may be used for QOS matching and a connection management mechanism for network resource allocation. We discuss fallback routing, and review some existing routing frameworks. We also present a new rule-based, call-by-call source routing strategy for integrated communication networks. >

Routing in Communications Networks

Abstract: I. CIRCUIT-SWITCHING NETWORKS. AT&Ts Dynamic Routing Network, G.R. Ash Dynamic Alternative Routing, R.J. Gibbens, F.P. Kelly, and P.B. Key II. PACKET-SWITCHING NETWORKS. Distance Vector Routing, G.S. Malkin and M.E. Steenstrup Inter-Domain Routing: EGP, BGP, and IDRP, Y. Rekhter Link State Routing, J. Moy AppleTalk Routing, A.B. Oppenheimer and F. Kuang SNA Routing, A. Garuge III. HIGH-SPEED NETWORKS. Routing in Optical Networks, J. Bannister, M. Gerla, and M. Kovacevic On Routing in ATM Networks, S. Gupta, K.W. Ross, and M. El Zarki Routing in the plaNET Network, I. Cidon and R. Guerin Deflection Routing, F. Borgonovo IV. MOBILE NETWORKS. Routing in Cellular Mobile Radio Communications Networks, J. Ketchum Packet Radio Routing, G.S. Lauder

A family of fault-tolerant routing protocols for direct multiprocessor networks

Abstract: Our goal is to reconcile the conflicting demands of performance and fault-tolerance in interprocessor communication. To this end, we propose a pipelined communication mechanism-pipelined circuit-switching (PCS)-which is a variant of the well known wormhole routing (WR) mechanism. PCS relaxes some of the routing constraints imposed by WR and as a result enables routing behavior that cannot otherwise be realized. This paper presents a new class of adaptive routing algorithms-misrouting backtracking with m misroutes (MB-m). This class of routing algorithms is made possible by PCS. We provide an analysis of the performance and static fault-tolerant properties of MB-m. The results of an experimental evaluation of PCS and MB-3 are also presented. This methodology provides performance approaching that of WR, while realizing a level of resilience to static faults that is difficult to achieve with WR. >

Bandwidth-delay based routing algorithms

Abstract: Multimedia applications often require guaranteed quality of service and resource reservation, which has raised a number of challenging technical issues for routing. We consider two new routing algorithms based on bandwidth and delay metrics. The implications of routing metrics on path computation are examined and the rationales behind the selection of bandwidth and delay metrics are discussed. Two new routing algorithms based on bandwidth and delay metrics are presented and some of their important properties are investigated.

ROMM routing on mesh and torus networks

Abstract: ROMM is a class of Randomized, Oblivious, Multi--phase, Minimal routing algorithms. ROMM routing offers a potential for improved performance compared to both fully randomized algorithms and deterministic oblivious algorithms, under both light and heavy loads. ROMM routing also offers close to best case performance for many common routing problems. In previous work, these claims were supported by extensive simulations on binary cube networks [30, 31]. Here we present analytical and empirical results for ROMM routing on wormhole routed mesh and torus networks. Our simulations show that ROMM algorithms can perform several representative routing tasks 1.5 to 3 times faster than fully randomized algorithms, for medium--sized networks. Furthermore, ROMM algorithms are always competitive with deterministic, oblivious routing, and in some cases, up to 2 times faster.

Routing in multihop packet switching networks: Gb/s challenge

Abstract: The authors survey networking solutions that have been proposed for high-speed packet-switched applications. Using these solutions as examples, they identify the specific problems resulting from very high transmission rates and explain how these problems influence the design of high-speed networks and protocols. They conclude that the solutions based on deflection routing are the most promising ones and suggest a number of directions for their evolution. By a packet-switching protocol we mean the network-specific portion of the third OSI layer (i.e., the network layer) of the protocol stack. One part of a packet-switching protocol (according to our definition) is the routing scheme, i.e., the set of rules that assign incoming packets to output links. In general, we can talk about the following three components of the communication subnetwork which are relevant from our point of view: the routing protocol; the congestion-control mechanisms that can be effectively incorporated into the routing protocol; and the network topology. These components are closely related to each other and together offer a single functionality. We discuss routing protocols and congestion-control mechanisms employed in contemporary packet-switched networks, not necessarily in networks operating at very high transmission rates. Then, following some basic definitions related to the topology component, we investigate the challenges posed by the Gb/s transmission rates. >

Distributed, scalable routing based on vectors of link states

Abstract: We have present a new method for distributed routing in computer networks and internets using link-state information. Link vector algorithms (LVA) are introduced for the distributed maintenance of routing information in large networks and internets.

A preservation-based multicast (RBM) routing protocol for mobile networks: initial route construction phase

Abstract: We propose a combined multicast routing, resource reservation and admission control protocol, termed Reservation-Based Multicast (RBM), that borrows the “Rendez-vous Point” or “Core” concept from multicast routing algorithms proposed for the Internet, but which is intended for operation in mobile networks and routes hierarchically-encoded data streams based on user-specified fidelity requirements, real-time delivery thresholds and prevailing network bandwidth constraints. The protocol exhibits the fully distributed operation and receiver-initiated orientation of these proposed algorithms; but, unlike them, the protocol is tightly coupled to a class of underlying, distributed, unicast routing protocols thereby facilitating operation in a dynamic topology. This paper focuses on the initial route construction phase, assumed to occur during a static “snapshot” of the dynamic topology, and is therefore applicable to fixed networks as well, e.g. the Internet.

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. This method may be used to develop deterministic, partially-adaptive, and fully-adaptive routing algorithms for wormhole-routed networks with arbitrary topologies. 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 use the model to develop new adaptive routing algorithms for 2D meshes. >

Communication in Multicomputers with Nonconvex Faults

Abstract: A technique to enhance multicomputer routers for fault-tolerant routing with modest increase in routing complexity and resource requirements is described. This method handles solid faults in meshes, which includes all convex faults and many practical nonconvex faults, for example, faults in the shape of L or T. As examples of the proposed method, adaptive and nonadaptive fault-tolerant routing algorithms using four virtual channels per physical channel are described.

Hierarchical distance-vector multicast routing for the MBone

Abstract: The exponential growth of the Multicast Back-bone (MBone) has resulted in increased routing overhead and processing costs. In this paper we propose a two-level hierarchical routing model as a solution to this problem. This approach involves partitioning the MBone into non-overlapping regions using DVMRP as the inter-region routing protocol; intra-region routing may be accomplished by any of a number of existing multicast protocols. Our design is flexible enough to accommodate additional levels of hierarchy, and protocols other than DVMRP at the higher levels. The unique feature of this approach is the independence of the higher level routing protocol from the subnet addresses, which allows for easy incremental deployment with small changes to existing intra-region protocols.

Method for using an IP address-based routing protocol in an ATM environment

Abstract: A technique for permitting continued use of IP (Internet Protocol) routing protocols in an Asynchronous Transfer Mode (ATM) network is implemented in each ATM system having route-computing responsibilities. When a call setup request is received, the routing system determines, from the ATM address of the target system, whether a routing protocol must be implemented. If a routing protocol must be implemented, data in an ACN (ATM Cluster Number) field and an HN (Host Number) field in the target ATM address is read and is imported into an IP-format address. This IP-format address is used in implementing the IP routing protocol.

Distance-vector routing

Abstract: Your program must start up and read a configuration file, the configuration file will provide you with the IP addresses of your directly connected neighbors, and the cost to reach those neighbors. Your program must connect to the IP addresses specified in the configuration file. Note that to bootstrap the network you are going to need to have your program retry connections that fail. Your program must also accept incoming IP connections, from neighbors, or from my master control client, which may inform you of a link cost change, or may ask you to deliver a message to a particular IP address. You can write your program in the language of your choice, however the program must run on Linux in the Olin 202 lab.

A 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, proposed by the author (1991, 1993), supplies sufficient conditions for an adaptive routing algorithm to be deadlock-free, even when there are cyclic dependencies between channels. Also, two design methodologies were proposed. Multicast communication refers to the delivery of the same message from one source node to an arbitrary number of destination nodes. A tree-like routing scheme is not suitable for hardware-supported multicast in wormhole networks because it produces many headers for each message, drastically increasing the probability of a message being blocked. A path-based multicast routing model was proposed by Lin and Ni (1991) for multicomputers with 2D-mesh and hypercube topologies. In this model, messages are not replicated at intermediate nodes. This paper develops the theoretical background for the design of deadlock-free adaptive multicast routing algorithms. This theory is valid for wormhole networks using the path-based routing model. It is also valid when messages with a single destination and multiple destinations are mixed together. The new channel dependencies produced by messages with several destinations are studied. Also, 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 of Lin and Ni are extended, so that they can take advantage of the alternative paths offered by the network. >

A routing protocol for finding two node-disjoint paths in computer networks

Abstract: In this paper, we present a routing protocol for finding two node-disjoint paths between each pair of nodes in a computer network. In the proposed protocol, each node in the network has the same procedure, which is driven by local information with respect to the network topology such as an adjacent node on a spanning tree in the network. Thus, the execution of the protocol can continue after changes of the network topology and load. The concept of spanning tree-based kernel construction is introduced to synchronize procedures under the distributed control of the protocol. The routing scheme based on the protocol possesses the enhanced capabilities of alternate routes and load splitting, which cope with failures and load variations in the network. Furthermore, even if topology changes occur which damage the obtained disjoint paths, the paths themselves can be updated efficiently.

Memory requirement for universal routing schemes

Abstract: Laboratoire de l'Informatique du Paral141isme-CNRS Ecole Normale Sup6rieure de Lyon 69364 Lyon cedex 07 France Abstract In this paper, we deal with the compact routing problem , that is implementing routing schemes that use a minimum memory size on each router. In [20], Peleg and Upfal showed that there is no hope to do that with less than a total f2(nl+llt2S+4)) memory bits for any stretch factor s z 1. We improve this bound for stretch factors s < 2 by proving that any near-shortest path routing scheme uses a total of Q(n2) memory bits. 1 Introduction The general routing problem in a network (as opposed to the permutation routing problem [18] or the broadcasting problem [6]) consists of fiding a routing protocol or routing function such that, for any source-destination pair, any message from the source can be routed to the destination. XY-routing [2] or e-cube routing [3] are such protocols. The efficiency of a protocol is measured in terms of latency (related to the length of the paths) and/or throughput (related to link or node congestion). Finding shortest paths in a network is easy [14], ~d finding paths minimizing congestion can be done easily for a large class of networks (namely Cayley graphs) [16]. However, the routings protocols that are obtained may be of no use from a VLSI point of view. Indeed, the implementation of these protocols may require such a large amount of hardware that they cannot be used in practice. For instance, implementing XY or e-cube routing is simple because routing is locally performed by respectively comparison and XOR-ing of the local address with the destination address. However, net works do not necessarily have the simde structure of meshes or hv-. percubes. For instance routing in pancake networks requires to decompose any given permutation in a product of particular ones, and this is definitely not easy (see Problem 39 in [9]). Also, networks may even have no Permission to make digital/hard copies of all or part of this material for personal or cIassroom use is granted without fee provided that the copies are not made or distributed for profit or commercial advantage, the copyright notice, the title of the publication and its date appear, and notice is given that copyright is by permission of the ACM, Inc. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires speeitic permission and/or …

A packet routing protocol for arbitrary networks

Abstract: In this paper, we introduce an on-line protocol which routes any set of packets along shortest paths through an arbitrary N-node network in O(congestion+diameter+log N) rounds, with high probability. This time bound is optimal up to the additive log N, and it was previously only reached for bounded-degree levelled networks.

Routing in a three-dimensional chip

Abstract: As the very large scale integration (VLSI) technology approaches its fundamental scaling limit at about 0.2 /spl mu/m, it is reasonable to consider three-dimensional (3-D) integration to enhance packing density and speed performance. With additional functional units packed into one chip in a 3-D space, computer-aided design (CAD) tools are demanded to ease the complicated design work. This paper presents a 100% completion achievable routing methodology. The routing methodology is based on the two-dimensional (2D) channel routing methodology; thus, it is called a 3-D channel routing methodology. With the routing methodology, a 3-D routing problem is decomposed into two 2D routing subproblems: intra-layer routing that interconnects terminals on the same layer, which can be done by using a 2-D channel router, and inter-layer routing that interconnects terminals on different layers. The inter-layer routing problem is transformed into a 2-D channel routing problem and the transformation is made in some 3-D channels. Detailed discussions are given for the 3-D to 2-D transformation. Optimization of the transformation is shown to be NP-complete. Thus, simulated annealing is used to optimize the transformation. >

Software Based Fault-Tolerant Oblivious Routing in Pipelined Networks.

Abstract: This paper presents a software based approach to fault-tolerant routing in oblivious, wormhole routed networks. When a message encounters a faulty output link it is removed from the network by the local router and delivered to the messaging layer of the local node’s operating system. The message passing software can re-route this message along a non-minimal oblivious path or via an intermediate node, which will forward the message to the destination. A message may encounter multiple faults and pass through multiple intermediate nodes. This paper discusses deadlock, livelock, and performance issues. Router designs are minimally impacted remaining compact, oblivious, and fast. Therefore this approach is a good candidate for incorporation into the next generation of wormhole routed multiprocessor networks.

A fuzzy control approach for adaptive traffic routing

Abstract: The application of fuzzy control to adaptive traffic routing in telephone networks is investigated. The authors use, on one hand, the properties of fuzzy control techniques and adaptive routing, on the other hand, to derive a routing system that is robust and efficient. They analyze the impact of various availability indicators on performance, which indicates that the choice of a suitable indicator must be made to characterize circuit group availability. When used in the fuzzy control framework the indicator used appears clearly to improve the performance of the routing algorithm as compared to existing routing systems. On the other hand, the use of this indicator in a classical way appears to be of poor utility. The study compares the performance of methods usually applied to adaptive traffic routing and the fuzzy control approach and shows that the fuzzy control approach could provide an effective framework for robust control of traffic routing in communications networks. Research studies still need to be carried out to develop fuzzy adaptive routing on different network structures and to evaluate its impact on performance. >

LLR routing in homogeneous VP-based ATM networks

Abstract: In ATM networks, a virtual path (VP) concept has been proposed to simplify traffic control and resource management. As a consequence, cell routing becomes more flexible and significant call setup processing can be reduced when resources are reserved on VP's. In this paper, we study the routing problem in homogeneous VP-based ATM networks in which VP's are used for traffic segregation such that all VC's in a VP have the same traffic characteristics and QOS requirement. Four adaptive routing algorithms based on the least loaded routing (LLR) concept are designed and evaluated. Our simulation results show that network blocking probability can be significantly reduced by LLR routing.

On routing in ATM networks

Abstract: Alternative routing of calls has long been acknowledged as a means of increasing call throughput and robustness in the telephone network. Given these performance gains, it is natural to consider dynamic routing of Virtual Circuits (VCs) in Asynchronous Transfer Mode (ATM) networks. Unlike telephone networks, VCs have heterogeneous bandwidth characteristics and Quality of Service requirements that the routing algorithm must take into account in order to optimize performance. In this paper we attempt to classify ATM networks according to the network characteristics that have the greatest bearing on the performance of dynamic routing algorithms; we also discuss appropriate routing algorithms for diierent classes of ATM network. The classiication is based on the degree of heterogeneity of the sources and the degree of statistical multiplexing.

On-line routing for permanent virtual circuits

Abstract: The paper considers the problem of routing a set of permanent virtual circuit requests over a backbone network. Several factors make this routing problem complicated. Routing decisions must be made on-line without any knowledge of future request sets. Furthermore, frequent rerouting to correct inefficiencies that can result from the on-line routing decisions is not possible since rerouting creates a service disruption for the customer. Finally, the forward and reverse bandwidth of a virtual circuit must be routed over the same single path. Using an extensive set of simulations, the paper evaluates several different strategies for on-line permanent virtual circuit routing. The authors find that a strategy based on results in competitive analysis and ideas from combinatorial optimization consistently provides the best performance. The problem of admission control is closely related to the problem of routing. The paper also provides a theoretical lower bound that suggests that non-greedy admission control is a fundamental component of an efficient on-line permanent virtual circuit routing algorithm.

Routing system for automatically routing a call to a multi-mode transceiver in a wireless network

Abstract: A routing system, and an associated method, for routing a call to a multi-mode transceiver. Selection of a service subscription pursuant to which calls are to be routed to the transceiver is made at the transceiver, and information related to the selected service subscription is transmitted to a service node and stored at the service node. When an originating party desires to place a call to the transceiver, the originating party accesses the information stored at the service node. Responsive to the information stored at the service node, the call is routed to the transceiver pursuant to the selected service subscription.

Dynamic routing in stochastic networks

Abstract: This paper reviews some current work on routing in loss and queueing networks. We describe two classes of bound on the performance of any dynamic routing scheme, together with some open questions concerning whether the bounds can be approached under certain limiting regimes. The rst class of bound is particularly appropriate for networks in heavy traac, where the key feature of a good routing scheme is its eeective utilization of various pooled resources identiied by a uid version of the routing problem. The second class of bound is particularly appropriate for highly connected networks, with many alternative paths. Again, a network ow representation is central, but this time involving a collection of Markov decision processes, one for each resource of the network. Despite their simplicity, the bounds are able to identify the great variety of qualitatively distinct behaviour expected of a good dynamic routing scheme, depending on a network's size, connectivity, asymmetry and degree of overload.