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Showing papers on "Link-state routing protocol published in 1996"


Journal ArticleDOI
TL;DR: This paper first examines the basic problem of QoS routing, namely, finding a path that satisfies multiple constraints, and its implications on routing metric selection, and presents three path computation algorithms for source routing and for hop-by-hop routing.
Abstract: Several new architectures have been developed for supporting multimedia applications such as digital video and audio. However, quality-of-service (QoS) routing is an important element that is still missing from these architectures. In this paper, we consider a number of issues in QoS routing. We first examine the basic problem of QoS routing, namely, finding a path that satisfies multiple constraints, and its implications on routing metric selection, and then present three path computation algorithms for source routing and for hop-by-hop routing.

1,769 citations


Journal ArticleDOI
TL;DR: WRP reduces the number of cases in which a temporary routing loop can occur, which accounts for its fast convergence properties and its performance is compared by simulation with the performance of the distributed Bellman-Ford Algorithm, DUAL, and an Ideal Link-state Algorithm.
Abstract: We present the Wireless Routing Protocol (WRP). In WRP, routing nodes communicate the distance and second-to-last hop for each destination. WRP reduces the number of cases in which a temporary routing loop can occur, which accounts for its fast convergence properties. A detailed proof of correctness is presented and its performance is compared by simulation with the performance of the distributed Bellman-Ford Algorithm (DBF), DUAL (a loop-free distance-vector algorithm) and an Ideal Link-state Algorithm (ILS), which represent the state of the art of internet routing. The simulation results indicate that WRP is the most efficient of the alternatives analyzed.

1,452 citations


Patent
15 Nov 1996
TL;DR: In this paper, the authors propose a distributed call rerouting service for packet switched data communications networks, where if a link on an active path fails, each switch receives a topology change notification and unmaps any connection involving the failed link.
Abstract: Method and apparatus providing connection-oriented services for packet switched data communications networks. Directory services include distributed discovery of MAC addresses and protocol alias addresses. Topology services include a link state topology exchange among switches, which provides each switch with a complete topology graph of the network. This enables an access switch receiving a data packet to determine a complete path from a source end system to a destination end system. Another service includes resolution of broadcast frames to unicast frames, in order to reduce the amount of broadcast traffic. Policy restrictions may be applied prior to connection setup. Path determination services enable multiple paths from a source to a destination. Connection management includes source routed mapping of connections on the desired path. A distributed call rerouting service is provided wherein if a link on an active path fails, each switch receives a topology change notification and unmaps any connection involving the failed link. A broadcast/unknown service provides restricted flooding of nonresolvable packets. Furthermore, connection-oriented switching is provided based on the source and destination MAC addresses as a connection identifier. Still further, resolution of networks outside the switch domain is enabled by access switches listening for network and server route advertisements and maintaining best routes to said networks and servers. The best route metrics may be combined with best path metrics to determine a path from a first access switch to an egress switch connected to the external network.

711 citations


Journal ArticleDOI
TL;DR: The main problems of stochastic vehicle routing are described within a broad classification scheme and the most important contributions are summarized in table form.

652 citations


Proceedings ArticleDOI
27 Mar 1996
TL;DR: A new associativity-based routing scheme where a route is selected based on nodes having associativity states that imply periods of stability, resulting in higher attainable throughput and the integration of ad-hoc routing into a BS-oriented wireless LAN environment, providing fault tolerance in times of base station failures.
Abstract: This paper presents a new, simple and bandwidth-efficient distributed routing protocol for ad-hoc mobile networks. Unlike the conventional distributed routing algorithms, our protocol does not attempt to consistently maintain routing information in every node. In an ad-hoc mobile network where mobile hosts are acting as routers and where routes are made inconsistent by mobile host movements, we employ a new associativity-based routing scheme where a route is selected based on nodes having associativity states that imply periods of stability. In this manner, the routes selected are likely to be long-lived and hence there is no need to restart frequently, resulting in higher attainable throughput. The association property also allows the integration of ad-hoc routing into a BS-oriented wireless LAN environment, providing fault tolerance in times of base station (BS) failures. The protocol is free from loops, deadlock and packet duplicates and has scalable memory requirements. Simulation results obtained reveal that shorter and better routes can be discovered during route re-constructions.

450 citations


Journal ArticleDOI
TL;DR: This paper is the second part of a work on the application of new search techniques for the vehicle routing problem with time windows and describes GENEROUS, the GENEtic ROUting System, which is based on the natural evolution paradigm.
Abstract: This paper is the second part of a work on the application of new search techniques for the vehicle routing problem with time windows. It describes GENEROUS, the GENEtic ROUting System, which is based on the natural evolution paradigm. Under this paradigm, a population of solutions evolves from one generation to the next by “mating” parent solutions to form new offspring solutions that exhibit characteristics inherited from their parents. For this vehicle routing application, a specialized methodology is devised for merging two vehicle routing solutions into a single solution that is likely to be feasible with respect to the time window constraints. Computational results on a standard set of test problems are reported, and comparisons are provided with other heuristics.

419 citations


Journal ArticleDOI
28 Aug 1996
TL;DR: It is found that Internet paths are heavily dominated by a single prevalent route, but that the time periods over which routes persist show wide variation, ranging from seconds up to days.
Abstract: The large-scale behavior of routing in the Internet has gone virtually without any formal study, the exception being Chinoy's analysis of the dynamics of Internet routing information [Ch93]. We report on an analysis of 40,000 end-to-end route measurements conducted using repeated "traceroutes" between 37 Internet sites. We analyze the routing behavior for pathological conditions, routing stability, and routing symmetry. For pathologies, we characterize the prevalence of routing loops, erroneous routing, infrastructure failures, and temporary outages. We find that the likelihood of encountering a major routing pathology more than doubled between the end of 1994 and the end of 1995, rising from 1.5% to 3.4%. For routing stability, we define two separate types of stability, "prevalence" meaning the overall likelihood that a particular route is encountered, and "persistence," the likelihood that a route remains unchanged over a long period of time. We find that Internet paths are heavily dominated by a single prevalent route, but that the time periods over which routes persist show wide variation, ranging from seconds up to days. About 2/3's of the Internet paths had routes persisting for either days or weeks. For routing symmetry, we look at the likelihood that a path through the Internet visits at least one different city in the two directions. At the end of 1995, this was the case half the time, and at least one different autonomous system was visited 30% of the time.

371 citations


Journal ArticleDOI
A. Birman1
TL;DR: This work uses a generalized reduced load approximation scheme to calculate the blocking probabilities for the optical network model for two routing schemes: fixed routing and least loaded routing.
Abstract: We study a class of all-optical networks using wavelength-division multiplexing (WDM) and wavelength routing, in which a connection between a pair of nodes in the network is assigned a path and a wavelength on that path. Moreover, on the links of that path no other connection can share the assigned wavelength. Using a generalized reduced load approximation scheme we calculate the blocking probabilities for the optical network model for two routing schemes: fixed routing and least loaded routing.

352 citations


01 Jan 1996
TL;DR: The interconnection network used in the Cray T3E multiprocessor is a bidirectional 3D torus with fully adaptive routing, optimized virtual channel assignments, integrated barrier synchronization support and considerable fault tolerance.
Abstract: This paper describes the interconnection network used in the Cray T3E multiprocessor. The network is a bidirectional 3D torus with fully adaptive routing, optimized virtual channel assignments, integrated barrier synchronization support and considerable fault tolerance. The routers are built with LSI’s 500K ASIC technology with custom transmitters/ receivers driving low-voltage differential signals at 375 MHz, for a link data payload capacity of approximately 500 MB/s.

339 citations


Journal ArticleDOI
TL;DR: The impact of node mobility and wireless communication on routing system design is discussed, and the set of techniques employed in or proposed for routing in mobile wireless networks is surveyed.
Abstract: Mobile wireless networks pose interesting challenges for routing system design. To produce feasible routes in a mobile wireless network, a routing system must be able to accommodate roving users, changing network topology, and fluctuat- ing link quality. We discuss the impact of node mobility and wireless communication on routing system design, and we survey the set of techniques employed in or proposed for routing in mobile wireless networks.

314 citations


Proceedings ArticleDOI
28 Aug 1996
TL;DR: This work identifies a link-cost or cost metric for "shortest-path" routing that performs uniformly better than the minimal-hop routing and shortest-widest path routing algorithms and proposes a novel prioritized multi-path routing algorithm in which low priority paths share the bandwidth left unused by higher priority paths.
Abstract: We study how to improve the throughput of high-bandwidth traffic such as large file transfers in a network where resources are fairly shared among connections. While it is possible to devise priority or reservation-based schemes that give high-bandwidth traffic preferential treatment at the expense of other connections, we focus on the use of routing algorithms that improve resource allocation while maintaining max-min fair share semantics. In our approach, routing is closely coupled with congestion control in the sense that congestion information, such as the rates allocated to existing connections, is used by the routing algorithm. To reduce the amount of routing information that must be distributed, an abstraction of the congestion information is introduced. Using an extensive set of simulation, we identify a link-cost or cost metric for "shortest-path" routing that performs uniformly better than the minimal-hop routing and shortest-widest path routing algorithms. To further improve throughput without reducing the fair share of single-path connections, we propose a novel prioritized multi-path routing algorithm in which low priority paths share the bandwidth left unused by higher priority paths. This leads to a conservative extension of max-min fairness called prioritized multi-level max-min fairness. Simulation results confirm the advantages of our multi-path routing algorithm.

Journal ArticleDOI
TL;DR: The theoretical background for the design of deadlock-free adaptive routing algorithms for virtual cut-through and store-and-forward switching is developed and a design methodology is proposed, which automatically supplies fully adaptive, minimal and non-minimal routing algorithms.
Abstract: This paper develops the theoretical background for the design of deadlock-free adaptive routing algorithms for virtual cut-through and store-and-forward switching. This theory is valid for networks using either central buffers or edge buffers. Some basic definitions and three theorems are proposed, developing conditions to verify that an adaptive algorithm is deadlock-free, even when there are cyclic dependencies between routing resources. Moreover, we propose a necessary and sufficient condition for deadlock-free routing. Also, a design methodology is proposed. It supplies fully adaptive, minimal and non-minimal routing algorithms, guaranteeing that they are deadlock-free. The theory proposed in this paper extends the necessary and sufficient condition for wormhole switching previously proposed by us. The resulting routing algorithms are more flexible than the ones for wormhole switching. Also, the design methodology is much easier to apply because it automatically supplies deadlock-free routing algorithms.

Proceedings ArticleDOI
18 Nov 1996
TL;DR: The innovation is the protection of the second-to-last information contained in the autonomous path attributes by the digital signatures, and the use of techniques developed for detecting loops in path-finding protocols to verify the selected route's path information.
Abstract: We analyze the security of the border gateway routing protocol and identify a number of vulnerabilities in its design and the corresponding threats. We then present a set of proposed modifications to the protocol which minimize or eliminate the most significant threats. The innovation we introduce is the protection of the second-to-last information contained in the autonomous path attributes by the digital signatures, and the use of techniques developed for detecting loops in path-finding protocols to verify the selected route's path information. With these techniques we are able to secure full path information in near constant space, and avoid the recursive protection mechanisms previously assumed necessary.

Journal ArticleDOI
TL;DR: Simulations of the one-fault-tolerant routing algorithm and other minimal and nonminimal routing algorithms in a two-dimensional mesh indicate that misrouting increases communication latencies significantly at high throughputs, so it is concluded thatMisrouting should be used only for increasing the degree of fault tolerance, never for just increasing adaptiveness.
Abstract: Previous methods of making wormhole-routed meshes fault tolerant have been based on adding virtual channels to the networks. This paper proposes an alternative method, one based on the turn model for designing wormhole routing algorithms. The turn model produces routing algorithms that are deadlock free, very adaptive, minimal or nonminimal, and livelock free for direct networks--whether or not they contain virtual channels. This paper illustrates how to modify the routing algorithms produced by the turn model to handle dynamic faults. This paper first describes how to modify the negative-first routing algorithm, which the turn model produces for n-dimensional meshes without virtual channels, to make it one-fault tolerant. Simulations of the one-fault-tolerant routing algorithm and other minimal and nonminimal routing algorithms in a two-dimensional mesh indicate that misrouting increases communication latencies significantly at high throughputs. The conclusion is that misrouting should be used only for increasing the degree of fault tolerance, never for just increasing adaptiveness. Finally , the paper describes how to modify the negative-first routing algorithm to make it (n - 1)-fault tolerant for n-dimensional meshes without virtual channels.

Patent
01 Nov 1996
TL;DR: In this paper, a method of interconnecting transistors and other devices in order to optimize area of a layout of a cell while honoring performance constraints and enhancing yield starts with a prerouting step.
Abstract: A method of interconnecting transistors and other devices in order to optimize area of a layout of a cell while honoring performance constraints (1502) and enhancing yield starts with a prerouting step (152) that routes adjacent transistors using diffusion wiring (1506), routes power and ground nets (1508), routes aligned gates (1510), routes all remaining aligned source/drain nets as well as any special nets (1512). Next, all of the remaining nets are routed using an area based router (1408). Nets are order based on time criticality or net topology (1602). A routing grid is assigned for all the layers to be used in routing (1604). An initial coarse routing is performed (1606). Wire groups are assigned to routing layers (1608). Routing is improved and vias are minimized (1610). A determination is then made whether the routing solution is acceptable (1612). If the routintg solution is not acceptable, the routing space is expanded and routing costs and via costs are modifyied to improve the routing solution. Finally, the best routing solution is picked (1414).

Patent
17 May 1996
TL;DR: In this paper, the authors propose a routing protocol for determining pre-established VPI trees rooted at each destination node, which manages the routes of these trees, while ensuring that there are at least two VPI tree from each source to each destination for reliability reasons.
Abstract: The present invention is a system and method for routing cells in a wireless communications network, wherein the communications network includes a plurality of switching nodes and the cells are routed according to destination-rooted virtual path identifier (VPI) trees. The present invention includes a routing protocol for determining preestablished VPI trees rooted at each destination node. The routing protocol manages the routes of these trees, while ensuring that there are at least two VPI trees from each source to each destination for reliability reasons, and that each destination node has multiple VPI trees for load-balancing reasons. The routing protocol includes an off-line procedure for the determination of the initial VPI trees. In order to handle changes in network traffic and conditions, the routing protocol updates the routes of the VPI trees in a dynamic and distributed fashion. These update procedures are triggered by congestion, link/node failures and link/node additions.

Proceedings ArticleDOI
22 Feb 1996
TL;DR: The fundamental issues in security of routing protocols are discussed, the basics of OSPF operation are reviewed, the proposed design is described, and remaining vulnerabilities are discussed.
Abstract: The routing protocols used to disseminate routing information throughout the Internet are not protected from intruders or faulty router participants. This paper reports on work in progress to protect the OSPF routing protocol through the use of cryptography, specifically, digital signatures. The routing information is signed with an asymmetric cryptographic algorithm, allowing each router recipient to check the source and integrity of the information. This paper discusses the fundamental issues in security of routing protocols, reviews the basics of OSPF operation, describes the proposed design and discusses remaining vulnerabilities.

Patent
11 Jul 1996
TL;DR: In this paper, an electronic messaging system which has multiple sites and in which each site is defined by a unique address space and has connectivity to at least one other site, messages are sent by receiving at a first site message routing information from a second site.
Abstract: In an electronic messaging system which has multiple sites, and in which each site is defined by a unique address space and has connectivity to at least one other site, messages are sent by receiving at a first site message routing information from a second site. The message routing information defines routes from the second site to one or more of the plurality of sites. The received message routing information is assimilated into previously known routing information to generate an updated accumulation of routing information. The updated accumulation of routing information is used to route messages to one or more of the plurality of sites. The updated accumulation of routing information may be replicated to still other sites in the messaging system, which in turn assimilate the information into their respective collections of known routing information. This process of receiving, assimilating and replicating may be repeated until each of the sites has substantially the same updated accumulation of routing information.

Patent
31 Dec 1996
TL;DR: In this paper, a routing means is employed to route the cells received at the inputs of the switch to outputs using routing information in which a number of the cells are misrouted by the routing means during the process of routing the cells to the outputs.
Abstract: A switch that has a plurality of inputs in which cells are received at these inputs. Each cell received at the inputs of the switch contain routing information. A routing means is employed to route the cells received at the inputs of the switch to outputs using routing information in which a number of the cells are misrouted by the routing means during the process of routing the cells to the outputs. Bus means is employed to route a cell to the destination in which the bus means is connected to the routing means. The bus means routes misrouted cells that are misrouted from the destination by some selected amount.

Proceedings ArticleDOI
12 Aug 1996
TL;DR: A novel deadlock-free adaptive routing algorithm is proposed to allow irregular interconnection of cut-through switches and some heuristics are suggested in terms of the selection of Eulerian trails, the avoidance of long routing paths, and the degree of adaptivity.
Abstract: Many cut-through switches, which can greatly reduce network latency, are commercially available for the construction of high-speed local area networks. The interconnection of cut-through switches provides an excellent network platform for high-performance workstation clusters. A novel deadlock-free adaptive routing algorithm is proposed to allow irregular interconnection of cut-through switches. The adaptive routing algorithm is based on two unidirectional adaptive trails constructed from two opposite unidirectional Eulerian trails. Some heuristics are suggested in terms of the selection of Eulerian trails, the avoidance of long routing paths, and the degree of adaptivity. Extensive simulation experiments based on a more realistic finite input source model are conducted to evaluate the network performance under different network parameters and traffic conditions. Both bimodal and bursty messages are considered. Such switch-based irregular networks are truly incrementally scalable and have potential to be reconfigured to adapt to the dynamics of network traffic conditions.

Patent
12 Jun 1996
TL;DR: In this paper, explicit routing advertisements are generated by the specific router and contain information regarding the selected path and forwarded to each next hop router to propagate the routing information to further propagate the information.
Abstract: A system for providing explicit routing functions in a connectionless network. A specific router selects a path through the connectionless network to a destination. Explicit routing advertisements are generated by the specific router and contain information regarding the selected path. Routing state is installed according to information contained in the explicit routing advertisements. The explicit routing advertisements are forwarded to each next hop router. Each next hop router installs routing state, generates the explicit routing advertisement, and forwards the explicit routing advertisement to further propagate the routing information.

Journal ArticleDOI
TL;DR: This paper considers optical networks with and without switches, and different types of routing in these networks, and presents optimal or near-optimal constructions of optical networks in these cases and algorithms for routing connections, specifically permutation routing for the networks constructed here.
Abstract: This paper studies the problem of dedicating routes to connections in optical networks. In optical networks, the vast bandwidth available in an optical fiber is utilized by partitioning it into several channels, each at a different optical wavelength. A connection between two nodes is assigned a specific wavelength, with the constraint that no two connections sharing a link in the network can be assigned the same wavelength. This paper considers optical networks with and without switches, and different types of routing in these networks. It presents optimal or near-optimal constructions of optical networks in these cases and algorithms for routing connections, specifically permutation routing for the networks constructed here.

Proceedings ArticleDOI
24 Mar 1996
TL;DR: A framework for the modeling of multipath routing in connectionless networks that dynamically adapt to network congestion is presented, which regulates the parameters of the destination-oriented permit buckets and guarantees that all portions of a multipath are loop free.
Abstract: We present a framework for the modeling of multipath routing in connectionless networks that dynamically adapt to network congestion. The basic routing protocol uses a short-term metric based on hop-by-hop credits to reduce congestion over a given link, and a long-term metric based on end-to-end path delay to reduce delays from a source to a given destination. A worst-case bound on the end-to-end path delay is derived under three architectural assumptions: each router adopts weighted fair queueing (or packetized generalized processor sharing) service discipline on a per destination basis, a permit-bucket filter is used at each router to regulate traffic flow on a per destination basis, and all paths are loop free. The shortest multipath routing protocol regulates the parameters of the destination-oriented permit buckets and guarantees that all portions of a multipath are loop free.

Patent
30 Dec 1996
TL;DR: In this article, a method of and system for routing switched termination telephone calls in accordance with international routing requirements and with consideration of available network capacity is presented. But this method requires the switch sends a query identifying the first country as the country of origin for the call and the second country as a country of termination to a service control point of the international carrier.
Abstract: A method of and system for routing switched termination telephone calls in accordance with international routing requirements and with consideration of available network capacity. A call is received at a switch of an international carrier. The switch sends a query identifying the first country as the country of origin for the call and the second country as the country of termination for the call to a service control point of the international carrier. The service control point determines from the query that the call is an international call and sends a request for a routing translation to a regulatory routing platform of the international carrier. The regulatory routing platform determines an optimal route for the call in accordance with international regulatory routing requirements.

Journal ArticleDOI
TL;DR: Another fault-tolerant routing algorithm, which requires only a constant of five virtual networks in wormhole routing to ensure the property of deadlock freeness for a hypercube of any size, is presented in this research.
Abstract: We investigate fault-tolerant routing which aims at finding feasible minimum paths in a faulty hypercube. The concept of unsafe node and its extension are used in our scheme. A set of stringent criteria is proposed to identify the possibly bad candidates for forwarding a message. As a result, the number of such undesirable nodes is reduced without sacrificing the functionality of the mechanism. Furthermore, the notion of degree of unsafeness for classifying the unsafe nodes is introduced to facilitate the design of efficient routing algorithms which rely on having each node keep the states of its nearest neighbors. We show that a feasible path of length no more than the Hamming distance between the source and the destination plus four can always be established by the routing algorithm as long as the hypercube is not fully unsafe. The issue of deadlock freeness is also addressed in this research. More importantly, another fault-tolerant routing algorithm, which requires only a constant of five virtual networks in wormhole routing to ensure the property of deadlock freeness for a hypercube of any size, is presented in this paper.

Proceedings ArticleDOI
01 May 1996
TL;DR: It is proved that for every shortest path routing scheme, for any constant e, O < c < 1, and for every integer d such that 3 ~ d < En, there exists a n-node network of maximum degree d that locally requires @(n log d) bits of memory on El(n) nodes.
Abstract: In this paper, we deal with the compact routing problem on distributed networks, that is implementing routing schemes that use a minimum memory size on each node. We prove that for every shortest path routing scheme, for any constant e, O < c < 1, and for every integer d such that 3 ~ d < En, there exists a n-node network of maximum degree d that locally requires @(n log d) bits of memory on El(n) nodes. This optimal lower bound means that whatever you choose the routing scheme (interval routing, boolean routing, prefix routing, . ..). there exists a network on which one can not do better than routing tables.

01 Jan 1996
TL;DR: This dissertation study focuses primarily on multicast routing problems for real-time communication on high-speed connection-oriented wide-area networks, but it considers also the special cases of broadcast routing and unicast routing.
Abstract: Real-time network applications, e.g., multimedia applications and critical control applications, are evolving at a fast pace. These applications are resource-intensive, have stringent delay requirements, and in many cases involve more than two participants. Efficient multicast communication mechanisms are, therefore, necessary to support real-time applications. In this dissertation, we study five routing problems for real-time communication on high-speed connection-oriented wide-area networks. The objective of all problems we study is to optimize the utilization of the network resources without violating the delay requirements of real-time applications. We focus primarily on multicast routing problems, but we consider also the special cases of broadcast routing and unicast routing.

Proceedings ArticleDOI
01 Apr 1996
TL;DR: In this paper, a min-cost max-flow heuristic is proposed to handle multiple layers, pre-routed nets, and all-angle, octilinear or rectilevel wiring styles.
Abstract: Many practical routing problems such as BGA, PGA, pin redistribution and test fixture routing involve routing with interchangeable pins. These routing problems, especially package layout, are becoming more difficult to do manually due to increasing speed and I/O. Currently, no commercial or university router is available for this task. In this paper, we unify these different problems as instances of the interchangeable pin routing (IPR) problem, which is NP-complete. By representing the solution space with flows in a triangulated routing network instead of grids, we developed a min-cost max-flow heuristic considering only the most important cuts in the design. The heuristic handles multiple layers, prerouted nets, and all-angle, octilinear or rectilinear wiring styles. Experiments show that the heuristic is very effective on most practical examples. It had been used to route industry designs with thousands of interchangeable pins.

Patent
Maged E. Beshai1, James Yan1
16 Oct 1996
TL;DR: In this article, a routing protocol for an ATM switching network includes a plurality of switching nodes, each of which includes individual storage for storing routing messages for each outgoing link, and the routing messages stored at each node are processed independently and simultaneously by each node.
Abstract: A routing scheme for an ATM switching network includes a plurality of switching nodes, each of which includes individual storage for storing routing messages for each outgoing link. A call at a source node is routed through one possible routing path which requires only one or two links to complete a connection to a destination node. In such case, one of the routing paths is selected based on link state information concerning only the possible routing paths. If the call requires a route path which includes three or more links to the destination node, the source node performs a predefined sequential routing to its neighboring node before the neighboring node negotiates with selected intermediate nodes for a connection involving two links. The routing messages stored at each node are processed independently and simultaneously by each node. The main requirement is that routing decisions must be based on true link-state information. A protocol is devised for fast and efficient bulk processing while avoiding potential deadlocks.