Showing papers on "Node (networking) published in 1996"

IP Mobility Support

Abstract: This document specifies protocol enhancements that allow transparent routing of IP datagrams to mobile nodes in the Internet. Each mobile node is always identified by its home address, regardless of its current point of attachment to the Internet. While situated away from its home, a mobile node is also associated with a care-of address, which provides information about its current point of attachment to the Internet. The protocol provides for registering the care-of address with a home agent. The home agent sends datagrams destined for the mobile node through a tunnel to the care- of address. After arriving at the end of the tunnel, each datagram is then delivered to the mobile node.

Mobility support in IPv6

Abstract: This document specifies a protocol which allows nodes to remain reachable while moving around in the IPv6 Internet. Each mobile node is always identified by its home address, regardless of its current point of attachment to the Internet. While situated away from its home, a mobile node is also associated with a care-of address, which provides information about the mobile node's current location. IPv6 packets addressed to a mobile node's home address are transparently routed to its care-of address. The protocol enables IPv6 nodes to cache the binding of a mobile node's home address with its care-of address, and to then send any packets destined for the mobile node directly to it at this care-of address. To support this operation, Mobile IPv6 defines a new IPv6 protocol and a new destination option. All IPv6 nodes, whether mobile or stationary can communicate with mobile nodes.

World-wide-web server with delayed resource-binding for resource-based load balancing on a distributed resource multi-node network

Abstract: A multi-node server transmits world-wide-web pages to network-based browser clients. A load balancer receives all requests from clients because they use a virtual address for the entire site. The load balancer makes a connection with the client and waits for the URL from the client. The URL specifies the requested resource. The load balancer waits to perform load balancing until after the location of the requested resource is known. The connection and URL request are passed from the load balancer to a second node having the requested resource. The load balancer re-plays the initial connection packet sequence to the second node, but modifies the address to that for the second node. The network software is modified to generate the physical network address of the second node, but then changes the destination address back to the virtual address. The second node transmits the requested resource directly to the client, with the virtual address as its source. Since all requests are first received by the load balancer which determines the physical location of the requested resource, nodes may contain different resources. The entire contents of the web site is not mirrored onto all nodes. Network bottlenecks are avoided since the nodes transmit the large files back to the client directly, bypassing the load balancer. Client browsers can cache the virtual address, even though different nodes with different physical addresses service requests.

A practical approach for routing and wavelength assignment in large wavelength-routed optical networks

Abstract: We consider large optical networks in which nodes employ wavelength-routing switches which enable the establishment of wavelength-division-multiplexed (WDM) channels, called lightpaths, between node pairs. We propose a practical approach to solve routing and wavelength assignment (RWA) of lightpaths in such networks. A large RWA problem is partitioned into several smaller subproblems, each of which may be solved independently and efficiently using well-known approximation techniques. A multicommodity flow formulation combined with randomized rounding is employed to calculate the routes for lightpaths. Wavelength assignments for lightpaths are performed based on graph-coloring techniques. Representative numerical examples indicate the accuracy of our algorithms.

Interactive multimedia system

Abstract: An interactive multimedia audio/video communications system uses a lower data rate, non-deterministic graphics/command network having a plurality of desktop viewing stations and a network server. A separate, higher data rate, deterministic audio/video network is coupled to the plurality of desktop viewing stations using appropriate resources, such as an audio/video routing switcher and a professional disk recorder. A database contains a telephone directory so that when a user at one of the plurality of stations desires to communicate with another station, the user selects a telephone number and the server from the database determines the appropriate resources required to complete the connection. The server configures the necessary hardware via the graphics/command network to route the audio/video signals over the audio/video network from one station to the other. For conferences a quad splitter is used to combine up to four video signals into a singled composited video signal for display at the user's station. For communications with stations that exist on another node, the server communicates with the server at the other node and a codec farm is used to transfer the audio/video signals from the audio/video network of one system to the other. Thus the graphics/command network is left free for normal graphics operations once the audio/video communications has been established.

Computer system method and apparatus providing for various versions of a file without requiring data copy or log operations

Abstract: Various versions of a computer file are provided without requiring copying the file or logging changed data, so that the files have consistent user data. A program module responds to a system call argument and allocates another node in file system tables and copies metadata information from the old node into the new node, so that both nodes contain the same data block allocation information. Portions of the module set shadow pointers in the old node to point to the new node, and in the new node to point to the old node. Changes to data are made with respect to the new node and fresh physical data blocks are allocated for the changed blocks. A method includes the steps of allocating a new node for storing file allocation information for another version of an existing file; logically connecting the new node to the existing node for file name and other purposes; and replacing node identification information in the directory with the new mode identification. In other steps the method replaces the current node identification information of a file in the directory with previous node identification information obtained from the current node; and logically disconnects the current node from the previous node.

Authentication system based on periodic challenge/response protocol

Abstract: A wireless authentication system to control an operating state of a node being a computer, door control mechanism or any muti-state product based on the proximity of an authorized user to the node. The wireless authentication system comprises a security device implemented within the computer and a user authentication token ("token") in possession of the authorized user. A Challenge/Response protocol is configured between the security device and the token. The first successful Challenge/Response message exchange between the security device and the token places the node in an operational state allowing the authorized user access to the contents and/or networked resources of the node. Later Challenge/Response message exchanges are set to occur periodically to check whether the authorized user possessing the token has left the node unattended thereby causing the node to be placed in a non-operational state.

Methods and systems for providing a resource in an electronic network

Abstract: A method of providing a resource in an electronic network (20) which includes receiving a signal associated with machine-readable data (16) read from a network navigation device (10). The network navigation device (10) has a human-viewable image (14). The method further includes identifying the resource based upon the signal, and communicating content of the resource. The method can be performed by a node (24) of the electronic network (20).

A scalable and highly available web server

Abstract: We describe a prototype scalable and highly available web server, built on an IBM SP-2 system, and analyze its scalability. The system architecture consists of a set of logical front-end or network nodes and a set of back-end or data nodes connected by a switch, and a load balancing component. A combination of TCP routing and Domain Name Server (DNS) techniques are used to balance the load across the Front-end nodes that run the Web (httpd) daemons. The scalability achieved is quantified and compared with that of the known DNS technique. The load on the back-end nodes is balanced by striping the data objects across the back-end nodes and disks. High availability is provided by detecting node or daemon failures and reconfiguring the system appropriately. The scalable and highly available web server is combined with parallel databases, and other back-end servers, to provide integrated scalable and highly available solutions.

Communication system and methods utilizing a reactively controlled directive array

Abstract: A reactively controlled directive antenna array that has a single central monopole or dipole as a radiating element excited directly by a feed system. A plurality of parasitic elements surround the radiating element and through changing the state of the parasitic impedance causing the antenna to be in an omni directional or beam pointing mode according to whether the parasitic elements are open circuited or short circuited. A computer modem and memory including stored programs control the antenna array in an omnidirectional or directive mode to locate, identify and communicate with nodes in a wireless communication network. A stored table is created in the memory indicating the antenna direction for communicating with each node in the network. Using the stored table, the computer initiates a communication sequence with a selected node, the sequence having the advantages of improved signal sensitivity and angular discrimination for wireless communication systems.

An architecture for mobile radio networks with dynamically changing topology using virtual subnets

Abstract: An architecture adaptable to dynamic topology changes in multi-hop mobile radio networks is described. The architecture partitions a mobile network into logically independent subnetworks. Network nodes are members of physical and virtual subnets and may change their affiliation with these subnets due to their mobility. Each node is allocated an address based on its current subnet affiliation. We observe— especially in large networks with random topology—that partitioning of the network may result in significantly more balanced load than in one large multi-hop network, an attribute that can significantly improve the network's performance. The architecture is highly fault-tolerant, has a relatively simple location updating and tracking scheme, and by virtue of its load balancing feature, typically achieves a network with relatively high throughput and low delay. The addressing method, logical topology, mobility management and routing procedure are described, and network performance is evaluated.

Method and system at a host node for hierarchically organizing the links visited by a world wide web browser executing at the host node

Abstract: A host node is provided with an I/O port and a display monitor. The I/O port transmits packets to a specific one of the remotely accessible server nodes containing a request for information. In response, the I/O port receives packets containing requested information, entries describing other topics of information that can be provided from the specific server node and entries describing other server nodes. The display monitor has a view area on which images are displayed. The display monitor displays a hierarchically organized table. The table includes the entries describing remotely accessible server nodes and the entries describing topics of information that can be retrieved from the remotely accessible server nodes. The entries are hierarchically organized so as to indicate a hierarchical organization of the entries as provided for retrieval from the remotely accessible server nodes which hierarchical order of retrieval is independent of a specific order of retrieval by the host node.

Process control system including a method and apparatus for automatically sensing the connection of devices to a network

Abstract: A digital control system automatically senses when a new controller is attached to a network and determines the number and types of I/O Ports that are attached to the new controller. The digital control system formats and displays the I/O Port information upon request by a user. The digital control system program also includes an automatic configuration program that responds to sensing of a new controller by automatically configuring the input/output (I/O) subsystem. The user adds a new controller without setting any physical switches or nodes. A user optionally supplies configuration information for a device into a database, prior to connection of a device. Upon connection of the device, the device is automatically sensed and configured using the database configuration information, without setting of physical switches or node address information on the devices.

Network-based intelligent tutoring system

Abstract: A technique for providing a networked, distributed tutorial application having a direct manipulation graphical user interface displayable on an Internet client node is disclosed. The application has a first portion on an Internet server node and a second portion on the Internet client node, the first portion performing application specific subject matter processing and the second portion being substantially application independent in that this second portion is applicable in a wide variety of tutoring applications for generating and maintaining an appropriate user interface during user interactions. The second portion includes an Internet browser (e.g., a hypertext mark-up language browser) that is utilized for communicating with the server node to perform application subject matter specific processing. A user being tutored may create, delete or modify graphical objects whose data structure definitions are provided by the server node, each such object having, for example, a behavior or data structure representing the semantics of a tutorial subject matter entity. Such user interactions are accumulated and utilized on the client node to maintain, independently of any communication with the server node, an interactive user interface semantically consistent with both the tutorial application and the user's interactions.

Network management system with improved node discovery and monitoring

Abstract: A method and system for monitoring nodes in a network having at least one network management station and a plurality of nodes. A queue (10) stores polling messages for transmission to the nodes where each node is indexed by its network address. The network management station sends polling messages to the nodes in sequence at a predetermined rate controlled by a rate control mechanism (12). Polling messages are sent up to four times to a particular node. The transmission of these messages are recorded in a table which is indexed by the network address of each node, and by the time of the next scheduled timeout (the time period between successive polling messages) associated with each node. The network management station determines if another polling message should be sent to each of the nodes. If the fourth polling message has been sent to a particular node, it has been unacknowledged by that node and the timeout has expired, then the node is determined to have failed.

Learning texture discrimination masks

Abstract: A neural network texture classification method is proposed in this paper. The approach is introduced as a generalization of the multichannel filtering method. Instead of using a general filter bank, a neural network is trained to find a minimal set of specific filters, so that both the feature extraction and classification tasks are performed by the same unified network. The authors compute the error rates for different network parameters, and show the convergence speed of training and node pruning algorithms. The proposed method is demonstrated in several texture classification experiments. It is successfully applied in the tasks of locating barcodes in the images and segmenting a printed page into text, graphics, and background. Compared with the traditional multichannel filtering method, the neural network approach allows one to perform the same texture classification or segmentation task more efficiently. Extensions of the method, as well as its limitations, are discussed in the paper.

Knowledge based path set up and spare capacity assignment for distributed network restoration

Abstract: In a telecommunications network having a plurality of intelligent nodes (101-106) interconnected by multiple communication channels (121-128), alternate paths and spare channels (151-158) are set up for restoring traffic disrupted by failure to one or more of the communications channels. The alternate paths may be set up irrespective of the number of custodial node pairs, also referred to as leader/follower or sender/chooser pairs, that could simultaneously be involved in the restoration operation. The interconnected nodes (101-106) have bidirectional working and/or spare channels (131-138 and 151-158). There is stored at each node in the network participating in the recovery operation a spare channel manifest for each of the leader/follower combinations.

Internetwork address mapping gateway

Abstract: The present invention is an address mapping gateway, used in an internetwork link, that associates all nodes in a domain with a single network number (referred to as a domain network address), and provides gateway-mapped node addresses that are unique within the domain. The address mapping gateway dynamically substitutes the "globally-unique" domain network address and the "domain-unique" gateway-mapped node address for a network number and node address, respectively, of a network layer address of a packet header received from a source node in the domain. Conversely, when a packet is received for a destination node in the domain, the address mapping gateway substitutes the originally-assigned network number and node address for the domain network address and gateway-mapped node address, respectively, prior to forwarding the packet to the node. Specifically, the address mapping gateway maintains an address mapping table that provides a cross-reference between (1) a source node address and the network number of the local network in which the node resides, and (2) a gateway-mapped node address generated by the address mapping gateway. Upon receipt of a packet from the source node, the address mapping gateway creates a mapping entry in the address mapping table that node and performs an address translation to a globally-unique network layer address. On the other hand, upon receipt of a packet destined for a destination node in the domain, the address mapping gateway locates the mapping entry for the packet's gateway-mapped node address and performs a reverse address translation to the originally-assigned network layer address.

Method and apparatus for reordering frames

Abstract: A method and apparatus for coupling a plurality of channels of a communications network to a node. The node includes a plurality of ports, each adapted for connection to a corresponding channel and a system interface adapted for connection to a plurality of node clients in the form of host computers, peripheral devices, network interfaces, etc. The node includes a receiver and transmitter dedicated to each port and common circuitry for controlling and processing frames received and/or transmitted by the plurality of ports. A frame prioritization circuit forwards frames received by a selected port to a frame handler for processing and a frame routing circuit routes frames processed by the frame handler to at least one of the ports associated with at least one destination node. The node further includes a frame header buffer associated with each port for temporarily storing the header of each frame received by the respective port prior to forwarding of the header to the frame handler.

Deterministic selection of an optimal restoration route in a telecommunications network

Abstract: A deterministic approach further refines the self healing network (SHN) distributed restoration algorithm (DRA) used for restoring traffic disrupted between two adjacent nodes. Upon detection of a fault, the sender node constructs a restoration signal that includes a weighed identifier field. The restoration message is broadcast to tandem nodes each of which had been provisioned with a memory table having stored therein a plurality of weights each associated with a particular spare link connected to the node. Upon detection of an incoming restoration message, a tandem node retrieves from its table the weight associated with the spare link from which the restoration message was received. The weighed identifier is retrieved from the restoration message and updated with the weight that the tandem node had retrieved from its table. The updated weighed identifier is reinserted to the restoration message and the updated restoration message is broadcast to downstream nodes for further propagation to the chooser node. As the restoration message arrives at each succeeding tandem node, the weighed identifier continues to be updated. The chooser node, upon receipt of the restoration message, retrieves the weighed identifier and compares the weighed identifier with other weighed identifiers of other restoration messages received before a restoration time out. Based on this comparison, the chooser node chooses an alternate route with the best weighed identifier.

Pro-active message delivery system and method

Abstract: A pro-active message delivery system which routes digitally-encoded messages via public-switched telephone networks and wide area networks to most cost-effectively deliver the messages, subject to security, privacy, and availability considerations. In a preferred embodiment of the invention, digitally encoded messages entered into a wide area network, either directly or via a public-switched telephone network, are sent to their destination using the most cost-effective route, by calculating the cost of sending the message via the available routes, and selecting the lowest cost route. Generally, the lowest cost route might use the node on the wide area network closest to the recipient of the message, or might use or node located in an area which charges off-peak rates at the time of transmission.

Methods, systems and computer program products for endpoint pair based communications network performance testing

Abstract: Communications network performance is tested utilizing a test scenario simulating actual communications traffic on the network to be tested. The test scenario includes an endpoint node specific test protocol between an endpoint node pair including a first and associated second endpoint node on the network to be tested. A partner endpoint node test protocol is determined from the endpoint node specific test protocol and communicated to from the first endpoint node to the associated second endpoint node of the endpoint node pair. A plurality of endpoint node pairs may executed different endpoint node specific test protocols under a test scenario. A console node is provided on the network for establishing the test scenario and assigning the test scenario to endpoint node pairs and initiating execution of the test scenario. Performance data may be monitored at one of the endpoint nodes of each endpoint node pair and reported to the console node either as it is generated or after completion of the test.

Method and apparatus for encoding and using network resource locators

Abstract: Access to data resources on data communications networks is simplified by encoding data resource specifiers into a compressed form which can be stored in a service provider's telephone equipment and transmitted to a user. The service provider stores information objects (e.g., hypertext pages) on one or more host computers at a node of a computer network, and develops compressed, compact resource specifiers for the information objects. A translation of the compressed resource specifier is provided in the user's telephone/terminal device and/or the host computer for translating the compressed resource specifiers back into their uncompressed form. The service provider stores the compressed resource specifiers in his telephone equipment and transmits them to users in response to user requests, such as in DTMF format. A compatible telephone/terminal device at the user's site (e.g., a computer or smartphone) receives and stores the compressed resource specifiers. Subsequently, during a data communication session with the host computer the user can request the specified information objects by transmitting the resource specifier it received from the service provider. The host computer uses the resource specifier it receives from the user to retrieve the requested information and transmit it to the user. This technique eliminates problems associated with memorization, incorrect copying, and/or re-keying of full network resource specifiers.

Filters: QoS support mechanisms for multipeer communications

Abstract: The nature of distributed multimedia applications is such that they require multipeer communication support mechanisms. The multimedia traffic needs to be delivered to end-systems, networks, and end-users in a form that they can handle while satisfying the constraints imposed by the multimedia application. Quality-of-service (QoS) mechanisms that can ensure full quality media playout at high-performance workstations, while at the same time providing appropriately filtered lower quality media for playout at other end-systems, are required. Existing multicast support mechanisms are deficient for this purpose, in a heterogeneous environment, because they work on a common denominator premise where the quality delivered depends on the least capable link or node involved in the multicast session. This paper begins by discussing video compression; it proposes and analyzes the use of filtering mechanisms as means of supporting disparate receiver capabilities and QoS requirements. The paper describes the implementation of a number of filtering mechanisms and highlights the communications architecture within which these mechanisms are built. This architecture constitutes a specific network topology and a new protocol family developed within a UNIX-like operating system.

Method and apparatus for providing quality of service routing in a network

Abstract: A system for providing quality of service routing functions in a connectionless network having multiple nodes. The system generates a link resource advertisement for each node in the network. Each link resource advertisement includes information regarding link resources available on a particular node in the network. The system also generates resource reservation advertisements for each node in the network. Each resource reservation advertisement includes information regarding a particular node's current reservations for a data flow. Network paths are calculated in response to a quality of service request. The calculations are performed based on information contained in the link resource advertisements and resource reservation advertisements.

Atomic network switch with integrated circuit switch nodes

Abstract: An atomic type switch mesh is combined with standard local area network links, such as high speed Ethernet, and a bridge-like protocol to provide a high performance scalable network switch. The network switch comprises a plurality of switch nodes, a first set of communication links which are coupled between switch nodes internal to the network switch, and a second set of communication links which comprise network links from switch nodes on the border of the network switch to systems external to the network switch. The respective switch nodes include a set of ports (having more than two members) which are connected to respective communication links in either the first or second set of communication links. Each port in the set comprises a medium access control (MAC) logic unit for a connectionless network protocol, preferably high speed Ethernet. The switch nodes also include a route table memory which has a set of accessible memory locations that store switch route data specifying routes through the plurality of switch nodes within the boundaries of the network switch. Flow detect logic is coupled with the set of ports on the switch node, which monitors frames received by the set of ports and generates an identifying tag for use in accessing the route table memory. Finally, the switch node includes node route logic which is coupled with the flow detect logic, the route table memory and the set of ports. The node route logic monitors frames received by the set of ports to route a received frame for transmission out a port in the set of ports.

Radio system with suspension of packet data service during non-data service connection

Abstract: A method of operation of a radio system with data capability, for example a GSM cellular radio system with GPRS capability includes suspending data service while remaining logged on to the system and signalling from a remote station (10) to a serving data service support node (13) via a base station subsystem (11) that data service is suspended. In another aspect, data is exchanged over a data channel (100) during first time periods (102) and exchange of data over the data channel stops during second time periods (103) intermittent between the first time periods. During the second time periods paging requests communicated on a paging channel (101) are monitored at the remote station (10). A non-data service paging request is identified on the paging channel and the system responds to the non-data service paging request.

Optical path cross-connect node architectures for photonic transport network

Abstract: This paper explores the optical path cross-connect (OPXC) node architectures that are essential components of the optical path network. Optical path technologies will play a key role in the development of the platform on which the future bandwidth abundant B-ISDN should be created. This paper highlights the wavelength path (WP) and the virtual wavelength path (VWP) technologies, both of which can greatly enhance the path layer capability and the efficiency of network failure restoration. The OPXC, which handles optical paths, is constructed with an optical switching network. Various WDM-based switching networks, which are aimed at LAN applications, have been reported. On the other hand, few WDM-based switching networks for OPXC systems, which are applicable to the nationwide transport network, have been proposed. In this paper, we elucidate the functional conditions required to construct OPXC nodes for WP and VWP global networks. Next, we assess switching network architectures for their applicability to the transport network. It is shown that the OPXC architecture based on DC-switches (delivery and coupling switches) is superior to the other OPXC architectures in terms of optical losses, modularity, and upgradability. Finally, detailed evaluations of the DC-switch-based OPXC node are presented that confirm its feasibility.

Method and apparatus for transparently providing mobile network functionality

Abstract: A method and apparatus for transparently providing a remote node with mobile network functionality. One embodiment of the present invention includes a remote node contacting a service provider to establish a remote connection with a home network. In response, the service provider generated an authentication request, on behalf of the remote node to obtain access to the home network. The service provider then sends the authentication request to an authentication server residing at the home network. The service provider then establishes, on behalf of the remote node, a remote connection between the remote node and the home network to enable packets to be transferred between the remote node and the home network.

System for reading the status and for controlling the power supplies of appliances connected to computer networks

Abstract: A SNMP network comprises a power manager with a SNMP agent in TCP/IP communication over a network with a SNMP network manager. The power manager is connected to control several intelligent power modules each able to independently control the on/off power to several inter-networking devices in an equipment rack at a common remote node, e.g., a point-of-presence site. Power-on and load sensors within each intelligent power module are able to report the power status of each inter-networking device to the SNMP network manager with MIB variables in response to GET commands. The SNMP network manager is further able to reboot each inter-networking device by cycling the power on/off to its respective intelligent power module with the SET command provided in conventional SNMP management applications.