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Showing papers on "Link-state routing protocol published in 1991"


01 Jan 1991
TL;DR: This data structure is general enough to encompass protocol to link layer address translation such as the Address Resolution Protocol (ARP), and the End System to Intermediate System Protocol (ES−IS), and should apply to any hierarchical routing scheme, such as source and quality-of-service routing, or choosing between multiple Datakits on a single system.
Abstract: Packet forwarding for OSI poses strong challenges for routing lookups: the algorithm must be able to efficiently accommodate variable length, and potentially very long addresses. The 4.3 Reno release of Berkeley UNIX† uses a reduced radix tree to make decisions about forwarding packets. This data structure is general enough to encompass protocol to link layer address translation such as the Address Resolution Protocol (ARP), and the End System to Intermediate System Protocol (ES−IS), and should apply to any hierarchical routing scheme, such as source and quality-of-service routing, or choosing between multiple Datakits on a single system. The system uses a message oriented mechanism to communicate between the kernel and user processes to maintain the routing database, inform user processes of spontaneous events such as redirects, routing lookup failures, and suspected timeouts through gateways.

178 citations


Book
02 Jan 1991
TL;DR: The author addresses the problem of routing connections in a large-scale packet-switched network supporting multipoint communications with a formal definition of several versions of the multipoint problem, including both static and dynamic versions.
Abstract: The author addresses the problem of routing connections in a large-scale packet-switched network supporting multipoint communications. He gives a formal definition of several versions of the multipoint problem, including both static and dynamic versions. He looks at the Steiner tree problem as an example of the static problem and considers the experimental performance of two approximation algorithms for this problem. A weighted greedy algorithm is considered for a version of the dynamic problem which allows endpoints to come and go during the life of a connection. One of the static algorithms serves as a reference to measure the performance of the proposed weighted greedy algorithm in a series of experiments. >

154 citations


Patent
13 Nov 1991
TL;DR: In this article, a transmission system transmits data among interconnected local area networks using a bridge coupled between local area network which senses whether the data originating node transmitted the data using transparent routing or source routing.
Abstract: A transmission system transmits data among interconnected local area networks using a bridge coupled between local area networks which senses whether the data originating node transmitted the data using transparent routing or source routing. The bridges provide interconnection at the MAC-layer and based upon information contained in the MAC-layer header, automatically perform either transparent routing or source routing, depending upon the type of routing used by the data originating node. In addition, the bridge provides source routing over multiple wide area channels to those nodes which use source routing.

144 citations


Journal ArticleDOI
TL;DR: This thesis examines the possibility of performing adaptive routing as an approach to further improving upon the performance and reliability of message-passing concurrent computers by exploiting the inherent path redundancy found in richly connected networks in order to perform fault-tolerant routing.
Abstract: Message-passing concurrent computers, also known as multicomputers, such as the Caltech Cosmic Cube [47] and its commercial descendents, consist of many computing nodes that interact with each other by sending and receiving messages over communication channels between the nodes. The communication networks of the second-generation machines, such as the Symult Series 2010 and the Intel iPSC2 [2], employ an oblivious wormhole-routing technique that guarantees deadlock freedom. The network performance of this highly evolved oblivious technique has reached a limit of being capable of delivering, under random traffic, a stable maximum sustained throughput of ~~45 to 50% of the limit set by the network bisection bandwidth, while maintaining acceptable network latency. This thesis examines the possibility of performing adaptive routing as an approach to further improving upon the performance and reliability of these networks. In an adaptive multipath routing scheme, message trajectories are no longer deterministic, but are continuously perturbed by local message loading. Message packets will tend to follow their shortest-distance routes to destinations in normal traffic loading, but can be detoured to longer but less-loaded routes as local congestion occurs. A simple adaptive cut-through packet-switching framework is described, and a number of fundamental issues concerning the theoretical feasibility of the adaptive approach are studied. Freedom of communication deadlock is achieved by following a coherent channel protocol and by applying voluntary misrouting as needed. Packet deliveries are assured by resolving channel-access conflicts according to a priority assignment. Fairness of network access is assured either by sending round-trip packets or by having each node follow a local injection-synchronization protocol. The performance behavior of the proposed adaptive cut-through framework is studied with stochastic modeling and analysis, as well as through extensive simulation experiments for the 2D and 3D rectilinear networks. Theoretical bounds on various average network-performance metrics are derived for these rectilinear networks. These bounds provide a standard frame of reference for interpreting the performance results. In addition to the potential gain in network performance, the adaptive approach offers the potential for exploiting the inherent path redundancy found in richly connected networks in order to perform fault-tolerant routing. Two convexity-related notions are introduced to characterize the conditions under which our adaptive routing formulation is adequate to provide fault-tolerant routing, with minimal change in routing hardware, The effectiveness of these notions is studied through extensive simulations, The 2D octagonal-mesh network is suggested; this displays excellent fault-tolerant potential under the adaptive routing framework. Both performance and reliability behaviors of the octagonal mesh are studied in detail. A number of

113 citations


Patent
05 Mar 1991
TL;DR: A class of switching networks is comprised of expansive logical clusters and/or dispersive logical clusters as discussed by the authors, which provide fault tolerance and routing and for efficient routing in a non-blocking fashion.
Abstract: A class of switching networks is comprised of expansive logical clusters and/or dispersive logical clusters. These clusters are of low degree. The class of networks include multibutterfly networks as well as multi-Benes networks. These networks provide for fault tolerance and routing and for efficient routing. Moreover, routing is provided in a non-blocking fashion.

96 citations


Journal ArticleDOI
TL;DR: The performances of two classes of routing algorithms are evaluated and compared in terms of revenue generated and link failures, and the control mechanism of trunk reservations is shown to play an important role in all cases.
Abstract: The performances of two classes of routing algorithms, randomized and deterministic, are evaluated and compared in terms of revenue generated and link failures. The randomized algorithm evaluated is dynamic alternate routing, and for the deterministic algorithm, attempts to carry a call are made in a specific precomputed order. The design of the routing sequences depends upon analytic approximations based on fixed-point equations to evaluate network performance and heuristics for the complicated problem of network revenue maximization. The control mechanism of trunk reservations is shown to play an important role in all cases. The performances of the algorithms were evaluated on a fully connected six-node network, the data for which were extracted from a realistic network. The design tools, time constants of various algorithms, and hybrid algorithms developed using the evaluation results are described. >

85 citations


Proceedings ArticleDOI
18 Nov 1991
TL;DR: A neural network computation algorithm is introduced to solve the optimal traffic routing in a general N-node communication network and the knowledge about the number of links between each origin-destination pair is not required by the algorithm, therefore it can be applied to a more general network.
Abstract: A neural network computation algorithm is introduced to solve for the optimal traffic routing in a general N-node communication network. The algorithm chooses multilink paths for node-to-node traffic which minimize a certain cost function. Unlike the algorithm introduced earlier in this area, knowledge of the number of links between each origin-destination pair is not required by the algorithm, therefore it can be applied to variable-length path routing problems. The neural network structure for implementing the algorithm is a modified form of the one used by the traveling salesman algorithm. Computer simulation in a nine- and sixteen-node grid network showed that the algorithm performs extremely well in single and multiple paths. >

77 citations


Patent
03 Sep 1991
TL;DR: In this paper, the authors proposed a closed loop routing protocol for routing messages between a plurality of communications networks, where each routing manager recognizes whether a message passed to it is for outward transmission over the associated network; if this is not the case, the message is passed to the local routing manager of the next card.
Abstract: Message-routing apparatus is known for routing messages between a plurality of communications networks. Typically, the known apparatus comprises a respective network interface card for each communications network and a shared, processor-based, routing manager with which the cards communicate through a backplane bus system. In order to overcome the bandwidth limitations of such known apparatus, the present invention provides a local routing manager on each card and high-speed, point-to-point, links interconnecting the local routing managers in a closed loop. Each local routing manager recognizes whether a message passed to it is for outward transmission over the associated network; if this is not the case, the message is passed to the local routing manager of the next card. Any messages which the local routing managers are unable to route, are diverted to a shared routing manager.

76 citations


Proceedings ArticleDOI
01 Jun 1991
TL;DR: Preliminary results show that a class of channel muting problems cart be muted in height less than the Manhattan density.
Abstract: We present new channel routing algorithms and theory that consider the characteristic of net crossings. ‘llte routing strategy is based on parallel bubble sorting and river routing tectilques. A fiction named POTENTfAL, cart be evaluated to indicate the required channel height for a given channel witbout actually carrying out the routing steps. Non-Manhattan wires as wefl as overlapping wires are introduced. Preliminary results show that a class of channel muting problems cart be muted in height less than the Manhattan density.

74 citations


Proceedings ArticleDOI
01 Apr 1991
TL;DR: In this paper, the authors present a multicast wormhole routing method for multicomputers adopting 2D-mesh and hypercube topologies. And they show that the dual-path routing algorithm requires less system resource, while the multipath routing algorithm creates less traffic.
Abstract: Efficient routing of messages is the key to the performance of multicomputers. Multicast communication refers to the delivery of the same message from a source node to an arbitrary number of destination nodes. Wormhole routing is the most promising switching technique used in new generation multicomputers. In this paper, we present multicast wormhole routing methods for multicomputers adopting 2D-mesh and hypercube topologies. The dual-path routing algorithm requires less system resource, while the multipath routing algorithm creates less traffic. More import antly, both routing algorithms are deadlock-free, which is essential to wormhole networks.

72 citations


Patent
12 Aug 1991
TL;DR: In this paper, a packet routing scheme is proposed to enable multiple packets to be routed simultaneously through a mesh-connected network, where the routing mask includes a broadcast bit and the packet must be simultaneously routed to all of the output links specified by the mask.
Abstract: A packet routing apparatus allows numerous packets to be routed simultaneously through a mesh connected network. The network consists of a number of interconnected switches which are coupled, in turn, to the hosts that are members of the local network. The switches are nonblocking switches that are coupled to each other and to the hosts by a multiplicity of point to point links. Each switch has a routing mechanism for automatically routing received packets toward their specified destinations. For each received packet the router generates a routing mask representing the output links that may be used to route the packet towards its destination. The routing mask includes a broadcast bit. If the broadcast bit is ON, the packet must be simultaneously routed to all of the output links specified by the routing mask. If the broadcast bit is OFF, the packet may be routed on any single one of the links specified by the routing mask. To ensure that every packet makes progress towards its destination, packets are processed in the order of their arrival by placing the corresponding routing masks in a queue. Periodically, the set of available output links is compared with all of the routing masks. Using a first come, first considered routing discipline, the first routing mask in the queue to match the available output lines is selected. A routing selection is then generated for the corresponding packet and the selected routing mask is removed from the queue.

Patent
Suresh Chalasani1, Anujan Varma1
16 Jul 1991
TL;DR: In this article, two distinct routing schemes are used to distribute the traffic among the two buffered multistage switching networks for processor-memory data traffic in a shared-memory multiprocessor computer system.
Abstract: A method and apparatus for routing processor-memory data traffic in a shared-memory multiprocessor computer system employs an interconnection network including two buffered multistage switching networks. Each of these networks can be used to route the data from any processing element to any memory element. Depending on the nature of the processor-memory traffic, two distinct routing schemes are used to distribute the traffic among the two networks. The first method distributes the memory accesses evenly among the two networks and maximizes performance when the memory accesses are uniformly distributed among the memory modules. However, when the traffic is highly non-uniform, a second routing method is used to confine the non-uniform part of the traffic to one network and the remaining part to the other network. The routing method is selected based on the prevailing traffic conditions. A distributed feedback mechanism detects the change in traffic conditions and changes the routing method accordingly. A traffic monitoring circuit within each memory module monitors the traffic into the memory module continuously and senses a change in the traffic condition. The condition is conveyed to the processing elements by means of a status flag associated with each response message from the memory module to processing elements. The processing elements respond to a change in traffic condition by switching to the alternate routing method.

Proceedings ArticleDOI
07 Apr 1991
TL;DR: Routing algorithms are proposed for setting up calls on a circuit-switched basis in linear lightwave networks (LLN), i.e., networks composed only of linear components, including controllable power combiners and dividers, and possibly linear (non-regenerative) optical amplifiers.
Abstract: Routing algorithms are proposed for setting up calls on a circuit-switched basis in linear lightwave networks (LLN), i.e., networks composed only of linear components, including controllable power combiners and dividers, and possibly linear (non-regenerative) optical amplifiers. The overall problem is decomposed into three subproblems: (1) physical path allocation, (2) checking for violations of the special optical constraints on the allocated physical path, and (3) channel assignment. Only point to point connections are considered. The physical path allocation technique uses the K-shortest path algorithm and tries to minimize the number of sources potentially interfering with each other, as a result of the incoming call. A channel assignment heuristic that tends to spread out calls evenly among the available channels works better than one that tries to maximize channel reuse. >

Journal ArticleDOI
TL;DR: In this article, a general framework for calculating a reliability measure for several types of flow networks is presented, which allows reliability analysis for complicated systems such as communication, electric power, and transportation networks, based on the notion of routing and rerouting after a failure.
Abstract: A general framework is presented for calculating a reliability measure for several types of flow networks. This framework allows reliability analysis for complicated systems such as communication, electric power, and transportation networks. The analysis is based on the notion of routing and rerouting after a failure. Modeling approaches are discussed for each type of system surveyed. A mathematical description of the system, measures of performance, a mathematical model of failures, routing models, and (if available) routing algorithms are discussed for every system. >

Proceedings ArticleDOI
01 Jun 1991
TL;DR: A multi-layer topological router for generating rubberband sketches is described, which uses hierarchical togdown partitioning and successive refinement to help correct mistakes made before more detailed local information is discovered.
Abstract: A multi-layer topological router for generating rubberband sketches is described. The router uses hierarchical togdown partitioning to perform global routing for all nets simultaneously. I t combines this with successive refinement to help correct mistakes made before more detailed local information is discovered. Layer assignment is performed during the partitioning process to generate routing that has fewer vias and is not restricted to one-layer one-direction. The local router uses a region connectivity graph to generate shortest-path rubber-band routing.


Proceedings ArticleDOI
02 Dec 1991
TL;DR: A new adaptive routing algorithm is evaluated under different load conditions and compared with other algorithms, showing that the new design methodology supplies faster routing algorithms, at least for those networks with a high connectivity.
Abstract: A new theory for the design of deadlock-free adaptive routing algorithms for wormhole and store-and-forward routing as well as two design methodologies have been proposed previously. In this paper, a new adaptive routing algorithm, obtained from the application of the former theory to the binary n-cube, is evaluated under different load conditions and compared with other algorithms. The results show that the new design methodology supplies faster routing algorithms, at least for those networks with a high connectivity. >

Journal ArticleDOI
01 Apr 1991
TL;DR: A survey of some packet-switched routing methods for massively parallel computers is presented, and three nonadaptive techniques and some adaptive routing algorithms are discussed.
Abstract: A survey of some packet-switched routing methods for massively parallel computers is presented. Some of the techniques are applicable to both shared-memory and message-passing architectures. These routing methods are compared in terms of their efficiency in supporting programming models, efficiency in mapping to parallel machines, and practicality. Among the outlined methods, three nonadaptive techniques and some adaptive routing algorithms are discussed. >

Journal ArticleDOI
TL;DR: Computational results indicate that combining this reduction with previous analysis of Brownian networks without discretionary routing leads to effective flow control policies for many moderately sized queueing network scheduling problems.
Abstract: Motivated by scheduling problems that arise in flexible manufacturing systems, we develop a heuristic procedure to obtain effective flow control sequencing, routing, and input control policies for multiclass queueing networks. The procedure employs a Brownian model of J. M. Harrison that approximates a multiclass queueing network with dynamic scheduling capability, if the total load imposed on each station in the queueing network is approximately equal to that station's capacity. In this paper, each customer class may be served at any of several different stations, and thus dynamic routing decisions are added to the sequencing and input control decisions already present in Harrison's model. Using previous heavy traffic results as a guide, we observe that, under heavy traffic conditions, a queueing network routing its customers to the queue where they will incur the shortest expected delay behaves very much like the reduced queueing network formed by pooling the appropriate servers. This observation leads to a proposed reduction of a Brownian network with discretionary routing to a simpler Brownian network without discretinary routing. Computational results indicate that combining this reduction with previous analysis of Brownian networks without discretionary routing leads to effective flow control policies for many moderately sized queueing network scheduling problems.

Journal ArticleDOI
TL;DR: A comparison is made of the open shortest path first (OSPF) and intermediate system-to-intermediate system (IS-IS) routing protocols in terms of their ability to route internet protocol (IP) traffic.
Abstract: A comparison is made of the open shortest path first (OSPF) and intermediate system-to-intermediate system (IS-IS) routing protocols in terms of their ability to route internet protocol (IP) traffic. Common characteristics of the two protocols are briefly indicated. The differences between the two are explored with respect to packet encoding, area partitions, level 2 partitions, injection of level 2 information, authentication, designated router election, link state packet propagation, synchronized parameter setting, and neighbor initialization. >

Journal ArticleDOI
TL;DR: It is shown that track-oriented greedy algorithms can be modified to solve other channel routing problems, and modified algorithms have good performance and show strong potential to outperform existing algorithms.
Abstract: A general approach for the channel routing problem is presented as a framework for a class of heuristic routing algorithms. The algorithm is shown to possess a backtracking capability that increases the chance of completing the routing with a minimum number of tracks. Since the concepts described are general, they can be applied to other channel problems, such as switchbox routing, three-layer routing, and multilayer routing, or even to the overlap model, with only a few modifications. It is shown that track-oriented greedy algorithms can be modified to solve other channel routing problems. As examples, the algorithm is modified to solve the Manhattan switch-box problem and channel routing problems in the overlap and knock-knee models. Preliminary results show that the modified algorithms have good performance and show strong potential to outperform existing algorithms. Applying the algorithm MCRP-ROUT to the benchmark Deutsch's difficult problem and Burstein's difficult problem, routing solutions of 19 tracks and six tracks, respectively, were obtained. >

Journal ArticleDOI
TL;DR: In this paper, a reliability measure that takes into account routing and rerouting policies after failures as well as the capacity of the network to satisfy its demand is proposed, based on the evaluation of the lost call traffic.
Abstract: A reliability measure that takes into account routing and rerouting policies after failures as well as the capacity of the network to satisfy its demand is proposed The measure, based on the evaluation of the lost call traffic, needs resolution of a routing model for the states of perfect functioning as well as the most probable failure states A type of routing model useful for network planning is also proposed The model is closer to reality and easier to implement than the other classical multicommodity formulations A convex-simplex implementation with a reoptimization feature explicitly adapted to the proposed model is used >

Proceedings ArticleDOI
01 Jun 1991
TL;DR: A new algorithm for over-the-cell channel routing in the standard cell design technology using the two-layer routing model, called WISER, which considers longest paths in the vertical constraint graph as well as channel density as a basis for choosing nets to route over the rows of standard cells.
Abstract: In this paper, we present a new algorithm, called WISER, for over-the-cell channel routing in the standard cell design technology using the two-layer routing model. The novelty of our approach lies in use of “vacant” terminals for over-the-cell routing. Furthermore, we consider longest paths in the vertical constraint graph as well as channel density as a basis for choosing nets to route over the rows of standard cells. Our approximation algorithm for net selection produces provably good results. Algorithm WISER has been tested on several benchmark examples, and experimental results show that WISER reduces the channel height by an average of 29% as compared to conventional channel routers. In addition, it reduces the total number of vias by 32% in the average case.

Proceedings ArticleDOI
01 Jun 1991
TL;DR: This paper deals with the problem of packet-switched routing in parallel machines and presents several new routing algorithms for different interconnection networks that are fully-adaptive and minimal.
Abstract: This paper deals with the problem of packet-switched routing in parallel machines. Several new routing algorithms for different interconnection networks are presented. While the new techniques apply to a wide variety of networks, routing algorithms will be shown for the bypercube, the 2-dinleusional mesh, and the shuffleexchange. The techniques presented for hypercubes and meshes are fully-adaptive and minimal. A similar technique can be devised for tori. A fully-adaptive and millimal routing is one in which all possible minimal paths bet,ween a source and a destination are of potential use at the time a message is injected into the network. Minimal paths followed by messages ultimately depend on the local congestion encountered in each node of the network. In the shuffle-exchange network, the routing scheme also exhibits adaptivity but paths could be up to 3 log N long for an N node machine. The shuflleexchange algorithm is the first adaptive and deadlockfree method that requires a small (and independent of N) number of buffers and queues in the routing nodes for that network. * ESLAI, Escuela Superior Latino Americana de Informitica, CC 3193,(1000) Buenos Aires, Argentina. t Computer Research and Advanced Applications Group, IBM Argentina, Ing. E. Bntti 275, (1300) Buenos Aires, Argentina. + Computer Science Dept., IBh’1 Almadeu Research Center, San

Journal ArticleDOI
TL;DR: The high-speed and predictable performance of these channel routing algorithms makes them valuable in assessing the difficulty of routing a particular configuration of logic blocks and suitable for use when calculating a cost metric in an iterative placement algorithm.
Abstract: A novel approach for the channel routing problem based on sorting is described. A router based on the bubble-sort for routing two point nets across a channel is presented. A lower and an upper bound on the channel width and an upperbound on the number of vias are given. The router is extended for handling multiterminal nets and single-sided connections. Results for multilayer channel routing are presented. The high-speed and predictable performance of these channel routing algorithms makes them valuable in assessing the difficulty of routing a particular configuration of logic blocks. This makes then suitable for use when calculating a cost metric in an iterative placement algorithm. >

Book ChapterDOI
01 Feb 1991
TL;DR: This paper presents an optimal algorithm for packet routing on a mesh-connected computer and shows how a single step of inter-processor communication can be thought of as a packet routing task.
Abstract: Packet routing is an important problem in parallel computation since a single step of inter-processor communication can be thought of as a packet routing task. In this paper we present an optimal algorithm for packet routing on a mesh-connected computer.

Proceedings ArticleDOI
01 Aug 1991
TL;DR: In this paper, a study on the performance of some new algorithms for deadlock-and lock-free adaptive routing is reported, which are the first known algorithms that require only two central queues per routing node.
Abstract: In thts paper, a strnulatton study on the performance of some new algorithms for deadlock- and lwelock-free adaptive routing is reported. Packetswztchcd fully -adaptive minzmal routing on the mesh and the hypercube as ezplored for dt~erent tn~ection models: stattc and dynamic. The algorithms stmu lated in this paper are the jirst known to be !ivelockand deadlock-free fully -adaptive minimal that requzre a moderate amount of hardware. These techniques need only two central queues per routing node. The performance of these schemes IS measured for dtfferent irafic models: random, complement, transpose, bit-reversal and leveied permutations. Several machine sizes are trted and critical parameters indicating the performance of the routing algorithms are measured such as throughput, maximum and average latency, effective tn~ectaon, and saturation point. In the case of the mesh network, the new method w compared to an obltvzous scheme based on a simtlar routing node model. In the present versaon of thts paper, stm u!atton results are reported for hypercubes up to 16K nodes and for meshes of 11{ nodes. Ftnallyl a fu!iy-adaptwe minzmal worm-hole routing algorathm for the torus network wiil be presented. This technique is dead!ock- and hvelock-free and requuvs only 8 vzrtual channels per physzcal bzdzrectzonal link for zts implementation. Szmu!ations are currently being performed to determme the practical performance of this routing method.


Proceedings Article
01 Jan 1991
TL;DR: A performance comparison between the star and hypercube graph using the unsafety vectors routing algorithm under different working conditions reveals that the hypercube is of superior performance compared to the star graph in the presence of low fault rates, but its performance under high fault rates falls short of that of the stargraph.
Abstract: This paper presents a fault tolerant routing algorithm for the star graph. The suggested algorithm is based on the concept of unsafety vectors, originally proposed for hypercubes. In this algorithm, each node starts by computing a first level unsafety set, composed of the set of unreachable neighbors. It then performs some exchanges with its neighbors to determine the unsafety nodes. After that, all nodes have the addresses of all faulty nodes. Based on the information gathered in each node, faulttolerant routing between a source node and a destination node is realized. We conducted a performance comparison between the star and hypercube graph using the unsafety vectors routing algorithm under different working conditions. The results obtained through simulation experiments reveal that the hypercube is of superior performance compared to the star graph in the presence of low fault rates. But its performance under high fault rates falls short of that of the star graph.

17 Mar 1991
TL;DR: To meet the special requirements of a decentral and highly mobile network the new multihop strategy MARION (multiple adaptive routing in mobile networks) is introduced.
Abstract: One of the common problems in mobile packet radio networks (PR'nets) is that mobile subscribers have to reach a stationary infrastructure. Multihop protocols enable communication to infrastructure contact points (beacons) which are out of transmission range. To meet the special requirements of a decentral and highly mobile network the new multihop strategy MARION (multiple adaptive routing in mobile networks) is introduced. Efficiency and packet delay are the main criteria for the final evaluation.