Showing papers on "Node (networking) published in 1995"

Routing and wavelength assignment in all-optical networks

Abstract: Considers routing connections in a reconfigurable optical network using WDM. Each connection between a pair of nodes in the network is assigned a path through the network and a wavelength on that path, such that connections whose paths share a common link in the network are assigned different wavelengths. The authors derive an upper bound on the carried traffic of connections (or equivalently, a lower bound on the blocking probability) for any routing and wavelength assignment (RWA) algorithm in such a network. The bound scales with the number of wavelengths and is achieved asymptotically (when a large number of wavelengths is available) by a fixed RWA algorithm. The bound can be used as a metric against which the performance of different RWA algorithms can be compared for networks of moderate size. The authors illustrate this by comparing the performance of a simple shortest-path RWA (SP-RWA) algorithm via simulation relative to the bound. They also derive a similar bound for optical networks using dynamic wavelength converters, which are equivalent to circuit-switched telephone networks, and compare the two cases. Finally, they quantify the amount of wavelength reuse achievable in large networks using the SP-RWA via simulation as a function of the number of wavelengths, number of edges, and number of nodes for randomly constructed networks as well as de Bruijn networks. They also quantify the difference in wavelength reuse between two different optical node architectures. >

IP Version 6 Addressing Architecture

Abstract: This specification defines the addressing architecture of the IP Version 6 protocol [IPV6]. The document includes the IPv6 addressing model, text representations of IPv6 addresses, definition of IPv6 unicast addresses, anycast addresses, and multicast addresses, and an IPv6 node's required addresses.

Mobile networking method and apparatus

Abstract: An internetwork including a plurality of local area networks may include wireless and hard-wired local area networks. The internetwork may also include wide area network links between routers. The system includes routers between networks, which may be bridged networks. Certain routers are configured as home routers. Home routers bind two addresses for each mobile node on a given network when that node logs-in with a home router. Mobile nodes log-in with a home router that assigns a virtual address that does not change throughout a session. Each time, a mobile node roams to another network across a router boundary, the virtual address remains the same and all packets directed to the mobile node are received by the home router which advertises that it can reach the mobile node. As the mobile node roams, it reports back to the home router a local address to which the home router forwards all packets directed originally by correspondent nodes to the virtual address. Mobile nodes may log-in to a router many hops removed from a local area network of the situs. Mobile nodes may also roam across wide area links. The system is transparent to a user.

Structural matching in computer vision using probabilistic relaxation

Abstract: In this paper, we develop the theory of probabilistic relaxation for matching features extracted from 2D images, derive as limiting cases the various heuristic formulae used by researchers in matching problems, and state the conditions under which they apply, We successfully apply our theory to the problem of matching and recognizing aerial road network images based on road network models and to the problem of edge matching in a stereo pair. For this purpose, each line network is represented by an attributed relational graph where each node is a straight line segment characterized by certain attributes and related with every other node via a set of binary relations. >

Apparatus and method for transparent wireless communication between a remote device and a host system

Abstract: An apparatus and method is provided for transparent communication between a remote or mobile device and a fixed communication host network. The apparatus and method may include a remote network controller that logically resides between the host network and the existing infrastructure(s) that are used to provide communications network contact with one or more remote devices. The remote network controller is connected to the host communication network as a protocol-appropriate communications controller so that remote devices are indistinguishable to the host network from the locally-attached devices. Each remote device may be provided with an asynchronous serial data interface to communicate with a mobile data controller. The mobile data controller, in combination with the remote network controller, provides end-to-end data communication such that incompatible protocols are transparent to the remote device and host communication network. A router may be provided which selects a communications network in accordance with user configured parameters. The router communicates over a plurality of incompatible networks and is capable of using a variety of different protocols. Switching between the plurality of incompatible networks is transparent to the remote device and host communication network.

Method and apparatus for establishing communications with a remote node on a switched network based on hypertext dialing information received from a packet network

Abstract: An Internet type access system includes an autodialer for automatically establishing communications with a merchant's facility over a switch network while maintaining Internet connectivity over a packet data network. The autodialer, in combination with the merchant's server, coordinates between the Internet session and the newly established switched connectivity, the session history from the prior Internet session being supplied to a sales representative receiving the autodialed call. The sales representative is provided with a terminal for controlling the merchant's server to push data to the client in response to the interactive session simultaneously conducted over the switched network.

System and method for providing packet data and voice services to mobile subscribers

Abstract: A system and method for providing internet data and voice services to mobile subscribers is directed for use in cooperation with Internet Packet Data Network (IPDN) and an Advanced Intelligent Network (AIN) having an existing wireline switch. The system and method obviate the need for a mobile telephone switch and can include at least one mobile terminal having the functionality of a mobile host, at least one Home Location Register (HLR), a data base, a plurality of Radio Port Controllers (RPCs) in communication with at least one Radio Port (RP), an internet access node, a home agent, a Correspondent Host (CH) and a Visitor Location Register/Directory Number Manager (VLR/DN-MGR). The HLR is operative to store and provide subscription data and keep track of where at least one mobile terminal is registered in order to deliver calls thereto. The VLR/DN-MGR, together with the wireline switch, are operative to control the plurality of RPCs and coordinate the transmission of voice and data services.

A GRASP for the Vehicle Routing Problem with Time Windows

Abstract: This paper addresses the problem of finding the minimum number of vehicles required to visit a set of nodes subject to time window constraints. A secondary objective is to minimize the total distance traveled. Each node requires a predetermined amount of service in the form of pickups and deliveries. The fleet is homogeneous and is located at a common depot. Vehicle capacity is finite and split service is not permitted. A greedy randomized adaptive search procedure (GRASP) is used to obtain feasible solutions. Results are reported for standard 100 node data sets as well as for a number of real-world problems with up to 417 customers. The findings indicate that, in general, the proposed procedure outperforms current techniques and requires only a small fraction of the time taken by exact methods. To gauge the quality of the solutions, three different lower bounding heuristics were developed. The first considers the “bin packing” aspect of the problem with regard to vehicle capacity; the second is based on ...

Method for preempting connections in high speed packet switching networks

Abstract: High speed network nodes can establish new connections by preempting existing ones when insufficient bandwidth is available in the network. Numerous preemption priorities are arranged in a limited number of groups and a median priority level is defined within each group. This median, stored in the topology database of each node of the network, permits better bandwidth utilization per group while consuming very little memory space and generating very low traffic overhead.

System for managing topology of a network in spanning tree data structure by maintaining link table and parent table in each network node

Abstract: A topology manager within a data communication network including a number of nodes interconnected by bi-directional links, wherein each said node is provided with means for dynamically setting and storing within the node a full topology database including full parent-node-relationship references. The system is is capable of fast path determination and fast spanning tree recovery based on the topology database contents.

Networking policies for hub-and-spoke systems with application to the air transportation system

Abstract: Recently, hub-and-spoke networks employing central hub facilities to channel flows between interacting nodes have become popular with successful applications in ground and air transportation. In this paper, we introduce a framework for the design of this type of distribution network with networking policies and models together with exact and heuristic solution procedures. We consider two networking policies: (i) Nonstrict hubbing, in which channeling flows through hubs is not required but chosen if found cost efficient and (ii) strict and restrictive hubbing, in which all flows to/from a node are channeled through the same hub. Variations of these policies are discussed together with various aspects of air passenger and cargo transportation, effects of network organization on demand and network design under continuous economies of scale. The performances of the proposed algorithms and the effects of the networking policy implemented on the hub locations and the route structure are studied using data on ai...

Dynamically reconfigurable communications network and method

Abstract: A wireless, dynamically and autonomously reconfigurable link layered communication network and method. The network self-optimizes communication paths within the network. A plurality of communication nodes form the network with each node having a transceiver for receiving and transmitting messages. Prioritized routing lists to all other nodes are stored at each node and updated. Each communication node can be an origination node and a destination node as well as serving as message repeater nodes.

Method and apparatus for executing a distributed algorithm or service on a simple network management protocol based computer network

Abstract: The present invention is directed at both a method and an apparatus for executing a distributed algorithm or server in a Simple Network Management Protocol Version 1 (SNMPv1) based computer network. The invention involves configuring a peer arrangement of agent/manager nodes and encapsulating the algorithm or server into SNMPv1. In a peer configuration, each node acts as a manager node, the manager node sends a Get message to an agent node to read a certain location in an agent node's managed information base (MIB) and sends a Set message to an agent node to write to a certain location in an agent node's MIB. This peer configuration also provides that each node act as an agent node, the agent node sends a GetResponse message to a manager node in response to a Get message and sends a Trap message to a manager node in response to an event. Encapsulating of the algorithm or server within SNMPv1 involves mapping the proprietary protocol to the SNMPv1 messages and mapping the algorithm or server variables to certain locations in the MIB. When mapping the algorithm or server, algorithm command variables, placeholder variables, and data variables are assigned to certain locations within the MIB.

Virtual shared disks with application transparent recovery

Abstract: A system and method for recovering from failures in the disk access path of a clustered computing system Each node of the clustered computing system is provided with proxy software for handling physical disk access requests from applications executing on the node and for directing the disk access requests to an appropriate server to which the disk is physically attached The proxy software on each node maintains state information for all pending requests originating from that node In response to detection of a failure along the disk access path, the proxy software on all of the nodes directs all further requests for disk access to a secondary node physically attached to the same disk

Transmitting electronic mail by either reference or value at file-replication points to minimize costs

Abstract: Transmitting e-mail over a network. According to a preferred embodiment, a current node in the network receives an e-mail message to be distributed to at least one recipient. The e-mail message comprises an attachment reference comprising the network address of an attachment stored locally to a previous node of the network. The costs of forwarding the e-mail message given a previous network location of the attachment is compared to the costs of moving the attachment locally to the current node. A copy of the attachment is retrieved, stored locally to the current node, and the attachment reference is updated, in accordance with the comparison.

Displaying node-link structure with region of greater spacings and peripheral branches

Abstract: Node-link data defining a node-link structure are used to present a sequence of representations on a display. The last representation in the sequence is perceptible as a changed continuation of the first. Each representation includes bounded node features, each with a center of area and a nearest node spacing that define a mid-spacing circle. All mid-spacing circles together determine an outer convex hull enclosing a total area for the representation. The mid-spacing circles of a subset of more spaced node features determine an inner convex hull enclosing approximately half the total area and enclosing a region in which nearest node spacings are in general perceptibly greater than in another region outside the second convex hull. The node features also represent a peripheral branch with lower level nodes that are not represented by more spaced node features. In the peripheral branch, node features that share a parent have centers of area positioned approximately along an arc with sufficiently similar spacings from the center of area of the parent node feature and from adjacent node features that they are perceptible as a group of related node features. The inner convex hulls of the first and last representations include subsets of node features representing different sets of nodes. The sequence can produce a perception that one node feature's nearest node spacing increases while another's decreases. The representations can be presented by a series of iterations, and can be presented at animation speeds to produce a perception of continuously moving node features.

An adaptive congestion control scheme for real time packet video transport

Abstract: We show that modulating the source rate of a video encoder based on congestion signals from the network has two major benefits: the quality of the video transmission degrades gracefully when the network is congested and the transmission capacity is used efficiently. Source rate modulation techniques have been used in the past in designing fixed rate video encoders used over telephone networks. In such constant bit rate encoders, the source rate modulation is done using feedback information about the occupancy of a local buffer. Thus, the feedback information is available instantaneously to the encoder. In the scheme proposed, the feedback may be delayed by several frames because it comes from an intermediate switching node of a packet switched network. The paper shows the proposed scheme performs quite well despite this delay in feedback. We believe the use of such schemes will simplify the architecture used for supporting real time video services in future nationwide gigabit networks.

System for using a dialog session context to process electronic forms data on the world wide web

Abstract: An electronic document processing system is disclosed for a communications network, wherein the network protocol has the property of repeatingly breaking down each established communication connection between network nodes attempting to carry on a dialog session. Related document data is exchanged between a network server and a client node, wherein the network communication connection between the server and the client must be repeatedly re-established and the prior dialog session context must be reassociated with continued dialog session communications between the server and client. Accordingly, the server node embeds a dialog session identifier within each communication to the client so that a response from the client may return the identifier thereby allowing the server to associate new client input with previously stored input related to the dialog session. The present invention is useful in maintaining a dialog session on the World Wide Web network wherein the widely used hypertext transfer protocol is the network protocol. Further, the present invention allows the server to customize document templates for responding to a client node communication. For the World Wide Web, the document templates are encoded in an enhanced version of the hypertext mark-up language wherein portions of such templates are capable of being replaced with stored dialog session data for customizing a document (particularly, a fill-out form) to be used for responding to a client.

Distributed object networking service

Abstract: Remote procedure call (RPC) objects are provided in both a client node and a server node of a client-server network for invoking and responding to service requests generated by calls to local service objects. Specifically, the RPC objects comprise a "caller" object which, once instantiated, accepts service requests from client objects. A service request made by calling a function in the local service object is automatically routed by the caller object to a local service program if the requests can be serviced locally, or to a remote server node if the appropriate service program is located on the remote node. The RPC objects also include a "dispatcher" object which is located at the remote service node and receives incoming service requests. The service requests are actually satisfied by means of service functions which are part of service objects in the server node, but these latter service functions are associated with the local service objects by means of a "dictionary" located in the dispatcher object. In some cases, a service located at a remote node may itself need data or functions which, in turn, reside at other nodes. In this case, the dispatcher object is provided with additional "sub-objects" or "child" objects which include their own dispatcher objects. In this manner, incoming requests directed to the "parent" dispatcher object are forwarded to the child dispatcher objects for service.

Method and apparatus for connecting a wireless lan to a wired lan

Abstract: An internetworking node for providing internetworking services for mobile wireless nodes is disclosed. Each mobile wireless node is associated with at the most one internetworking node. Each mobile wireless node selects which internetworking node it will associate with. The internetworking node will then act for all wireless nodes associated to it in relaying messages between wireless nodes or between a wired LAN and the wireless nodes.

Routing method for setting up a service between an origination node and a destination node in a connection-communications network

Abstract: A setup procedure employing distributed hop-by-hop routing reduces the number of signaling messages needed to establish a service (i.e., connection), thus enhancing network performance. A service is setup between an origination node and a destination node which are a part of a network of communication nodes interconnected by links. Each node maintains a topological database representing the network topology. Initially, a setup message for initiating the service is transmitted from the origination node to a neighboring node that serves as a local node. The topological database is then updated after the local node receives the setup message by eliminating links connected to a particular set of nodes. This set of nodes includes those nodes other than the local node that have previously transmitted a setup or failure message for the service. A shortest path is next determined from the local node to the destination node over the updated topology and another setup message is transmitted from the local node to a first neighboring node in the shortest path. The previously-mentioned steps are repeated, beginning with the step of updating the topological database, where the neighboring node now serves as a subsequent local node. The steps are repeated until either a setup message reaches the destination node so that the service enters a connected state or no shortest path is found at the origination node, which indicates that the service has failed to enter a connected state.

Topology aggregation for hierarchical routing in ATM networks

Abstract: This paper provides a tutorial for topology arregation in large hierarchical communication networks. Specifically, it examines some issues of topology aggregation for hierarchical PNNI Routing in ATM networks, presents a complex node representation, and provides some guidelines for topology aggregation. There are two main reasons for topology aggregation. First, topology information must be compressed to avoid excessive complexity in topology adevertisement. Second, the internal topology of a network may have to be hidden for security reasons. A desirable topology aggregation method must adequately represent the topology of a given network for efficient routing and netowrk resource allocation, using a compact advertised topology.

BAHAMA: a broadband ad-hoc wireless ATM local-area network

Abstract: We describe the theory, design and ongoing prototyping of a wireless ATM LAN/PBX capable of supporting mobile users with multi-Mb/s access rates and multi-Gb/s aggregate capacities. Our proposed LAN consists of network nodes called portable base stations (PBS) providing microcell coverage. The PBSs are designed to be low-cost, compact and high-speed and can be relocated conveniently. We employ a concept of ad-hoc networking in the layout of the PBS-to-PBS interconnection. That is, the PBSs can be distributed in an arbitrary topology to form a backbone network and can be reconfigured with relative ease. The PBS-to-PBS backbone links are high-speed (Gb/s) for supporting high system capacity. Although they can either be wired or wireless, our emphasis is on wireless implementations. The user-to-PBS links, on the other hand, are primarily for mobile access (e.g., 2-20 Mb/s) and therefore are wireless. Wired connections from stationary users to PBSs are also possible. Typical mobile users are assumed to be laptops or notebook computers. Services supported include conventional data applications (e.g., over TCP/IP or SPX/IPX) as well as multimedia (video, voice and data) applications with QoS (quality-of-service) guarantees. A "aireless ATM" concept is proposed so as to provide seamless internetworking with other wired ATM local and wide-area networks. Algorithms and control in our network are highly distributed for simple implementations and ease of mobility management. A new wireless VP/VC concept and a homing algorithm are described to provide ATM cell routing and connections in the network. PBS hardware and software architectures are discussed. Call management, network management and signaling are designed for simplicity, high performance and modular implementations. A fast network restoration scheme is proposed to cope with the potential link or node failures in the ad-hoc network. Error control is addressed taking the unreliable wireless links into consideration. Finally, a prototyping project called BAHAMA (broadband ad hoc ATM anywhere) for demonstrating this network concept is briefly outlined.

Traffic management and congestion control for packet-based network

Abstract: In a packet-based communications network (100), a virtual connection is established between a source node (102a) and a destination node (102b), which may traverse one or more intermediate nodes (105). During the flow of packets along the virtual connection in a forward direction, from the source node (102a) to the destination node (102b), each node measures the utilization of critical resources (CUF), and this utilization information is inserted into return packets flowing in the backward (return) direction, from the destination node (102b) to the source node (102b). CUF is indicative of the maximum utilization of any resource in the virtual connection forward path. If the network utilization information indicates that the resources of a virtual connection are under-utilized, the submission rate (SIR) of packets onto the virtual connection is increased. However, if the network utilization information indicates that the resources of the virtual connection are over-utilized, the submission rate of packets onto the network at the source node is reduced.

Method and apparatus for determining characteristics of a path

Abstract: An information gathering mechanism efficiently acquires information about a path interconnecting a source node and a destination node in a computer network. The mechanism comprises a novel packet configuration for soliciting parameters pertaining to network characteristics from routers coupled to the path. This novel probe packet preferably has a flexible format so that it may be processed not only by routers configured to interpret this type of packet, but also those that are incapable of either supplying some of the parameters or, further, deciphering any of the contents of the packet.

Device, method and system for variable bit-rate packet video communications

Abstract: The present invention provides a device (100), method, and system for, in an entry node (102) of a packet communication network, transcoding (104) a received constant bit-rate video bitstream to a variable bit-rate video bitstream, packetizing (106) the variable bit-rate video bitstream into video packets for efficient transport of a video signal over a packet-switched network.

LARnet, a local access router network

Abstract: A novel local access network, LARNet, is proposed and demonstrated. A multifrequency laser, whose wavelength COMB94 is matched to that of a passive waveguide router in the remote node, is used as a downstream signal source. A 1.3-/spl mu/m commercially available LED provides the upstream signal. LARNet solves a major problem of WDM networks, the spectral alignment between the optical wavelengths of different channels. Furthermore. The expensive components are shared among all subscribers. Our measurements indicate that aggregate rates of 2 Gbps downstream and 155 Mbps upstream are feasible. >

Network apparatus and method for providing two-way broadband communications

Abstract: A communication network (e.g., a coax network or an optical fiber network) comprises a signal distribution network (e.g., fiber node FN) for transmitting communication signals downstream over a first communication path to a plurality of end user apparatuses connected thereto. At least one end user apparatus is arranged for sending the return signals downstream over at least part of the first communication path to a converter apparatus which collects the return signals and converts them to an upstream signal for transmission over a second separate communication path to the distribution unit.

The design of a European optical network

Abstract: This paper presents a number of design issues under consideration in the development of an all-optical network linking major centers in Europe. The proposed network is characterized by spanning a large geographical area, the diameter is in excess of 3000 km, but with a relatively small number of nodes (20). The study combines aspects of two optical network projects funded by the European Commission: COST 239-ultra-high capacity optical transmission networks and RACE 2028: multiwavelength transport network. The network uses multiwavelength technology and combines wavelength selection and space switching to achieve signal routing. One of the objectives of the study is to understand the extent to which transparency can be achieved in such a large network. For example the effect of using amplifiers to achieve transparency is to provide extremely long fiber paths in which non-linear effects may become significant and effectively limit the number of wavelengths that can be employed; this limit may be at conflict with the number of wavelengths required from a traffic viewpoint. The paper therefore considers capacity requirements, transmission limitations and node and network architecture issues. It is concluded that partitioning of the network may be necessary to maximize transparency and suggestions are made as to how this might be achieved. >