Abstract: A method of fulfilling a request for information content with a user-selectable version of a file containing that information content. Selection of a hyperlink to information content results in generation of a menu of versions of files containing that information content. The menu displays options for versions which are derivable therefrom by a computer program for converting files from one version to another version. Selection of an option for a materialized version results in transmission of the materialized version. Selection of an option for a version which is not materialized results in derivation of the user-selected version from either a materialized version or any other version from which the user-selected version may be derived. Apparatuses for carrying out the inventive method are also provided.

Abstract: A maximum-flow based route precomputation algorithm includes at least a route generation phase and a route selection phase, and determines one or more routes between at least a given pair of nodes in a network. In the route generation phase, a maximum-flow algorithm is applied to a first set of information characterizing links between the given pair of nodes in the network. The output of the maximum-flow algorithm is utilizable to generate a second set of information characterizing corresponding admissible flows. In the route selection phase, one or more routes are determined based on the second set of information using, for example, a shortest widest path (SWP) algorithm. The route generation and route selection phases may be repeated for each of a plurality of node pairs of the network.

Abstract: A system for and method of multi-protocol label switching (MPLS) network tuning. In one embodiment, the system includes a hot zone clearing subsystem that recursively identifies label switched paths (LSPs) to be rerouted from a defined hot zone subject to edges to be avoided. In that embodiment, the system further includes an LSP ordering subsystem, which is coupled to the hot zone clearing subsystem, that orders the LSPs to be rerouted to yield a migration sequence. The migration sequence is employable to reduce a load of the hot zone.

Abstract: A system for and method of, increasing provisionable bandwidth in a multiplexed communication link and a network management system incorporating the system or the method. In one embodiment, the system includes: (1) a defragmentation calculator that calculates a defragmentation of the communication link, the defragmentation containing at least one granularity, (2) a candidate slot selector, associated with the defragmentation calculator, that finds reduced cost candidate slots for the at least one granularity and (3) a circuit mover, associated with the candidate slot selector, that identifies target slots into which circuits occupying the candidate slots can be moved.

Abstract: A method for data path provisioning in a reconfigurable data network is disclosed. A data path between a source IP router and a destination IP router is determined taking into account the IP-subnets of the network interfaces of the IP routers included in the path. In one embodiment, the requirement that two IP routers can send packets via their connected interface if and only if the two interfaces are on the same subnet (i.e., the subnet constraint) is completely honored during the data path determination. In another embodiment, the data path is determined while allowing some number of violations of the subnet constraint. A transform network graph is computed and is used to determine the data path taking into account the IP-subnets.

Abstract: In accordance with one embodiment of the invention, a central server system computes a feasible stretch value for use in scheduling the servicing of job requests by a plurality of communication channels. A stretch value provides an indication of the delay experienced by each job request to complete, when the central server processes many jobs concurrently. A processing time is calculated for each job request based on the size of the job request and the bandwidth of the channel. Thereafter, a stretch value is proposed. The server system computes a deadline for each job to be the arrival time of the job request plus the product of the processing time and the proposed stretch value. Thereafter, each job request is scheduled, based on an “earliest deadline first” arrangement.

Abstract: In accordance with one embodiment of the invention, a broadcast server system computes a feasible stretch value for use in scheduling job requests. A stretch value provides an indication of the delay experienced by each job request to complete, when the broadcast server processes many jobs concurrently. A processing time is calculated for each job request based on, the size of the job request and the bandwidth of the server downlink. Thereafter, a stretch value is proposed. The server system computes a deadline for each job to be the arrival time of the job request plus the product of the processing time and the proposed stretch value. Thereafter, each job request is scheduled, based on an “earliest deadline first” arrangement, wherein the job request that has the earliest deadline is scheduled first, the job request having the next earliest deadline is scheduled second, etc. The proposed stretch value is deemed feasible if each pending job request can be completed prior to its deadline.

Abstract: A method for generating an approximate answer to a query in a database environment in which the database has a plurality of base relations. A query relating to a database is received, and an approximate answer to the query is generated such that the approximate answer is based on at least one join synopsis formed from the database. The method further includes steps of forming a sample-tuple set for at least one selected base relation of a plurality of base relations of a database such that each sample-tuple set contains at least one sample tuple from a corresponding base relation, and forming a join synopsis set for each selected base relation such that each join synopsis set contains a join synopsis for each sample tuple in a sample-tuple set. A join synopsis of a sample tuple is based on a join of the sample tuple and at least one descendent relation of the sample tuple. All join synopsis sets form a statistical summary of the database and are stored.

Abstract: An approximate querying method comprising grouping tuples within a database according to grouping attributes, determining how many tuples are needed to represent each group, selecting the tuples from a corresponding group to create a database sample, and querying the database sample. The database sample yields statistically unbiased answers when queried. The sample may be created and maintained without a priori knowledge of the data distribution within the database or the queries to be performed.

Abstract: In accordance with one embodiment, a method for scheduling the servicing of job requests in a point-to-point communication system having a central server providing job requests to a plurality of local channel servers. In a first step, the method receives a new job request at a central server. A performance of each local channel server is measured, and the job request is dispatched to one of the local channel servers for servicing thereby dependent upon the performance of each of the local channel servers. In one embodiment, the job request is dispatched to the local channel servers having the lowest current average flow time.

Abstract: A method for generating an approximate answer to a query in a database environment in which the database has a plurality of base relations. A query relating to a database is received, and an approximate answer to the query is generated such that the approximate answer is based on at least one join synopsis formed from the database. The method further includes steps of forming a sample-tuple set for at least one selected base relation of a plurality of base relations of a database such that each sample-tuple set contains at least one sample tuple from a corresponding base relation, and forming a join synopsis set for each selected base relation such that each join synopsis set contains a join synopsis for each sample tuple in a sample-tuple set. A join synopsis of a sample tuple is based on a join of the sample tuple and at least one descendent relation of the sample tuple. All join synopsis sets form a statistical summary of the database and are stored.

Abstract: A computer implemented method and apparatus for enhancing access to a file and communicating a file over a communications network using an indirect link. An indirect link is a logical hyperlink identifying a file to be retrieved, not by its electronic address, but by a logical representation. The link may denote the server on which the file exists, but does not identify the file's full address. Rather, the server or a proxy machine uses a look-up table which relates a logical link to an actual electronic address. This system helps minimize broken links, since a file can still be located on the server and accessed even if it has been relocated on the server since the link was established.

Abstract: The present invention provides various methods and apparatus for providing accurate estimates for point and range queries over two-dimensional rectangular data. However, the techniques of the present invention for rectangular data can be applied to data of other shapes, point data, or linear data. The present invention provides several grouping techniques for the approximating of spatial data. A method is disclosed for grouping a plurality of spatial inputs into a plurality of buckets. In one form of the present invention the plurality of spatial inputs, is grouped based on an equi-area partitioning technique. The equi-area partitioning technique can use the longest dimension of a bucket or bounding polygon as the criteria for splitting into further buckets or bounding polygons. An equi-count technique can also be used wherein the buckets are split using the highest projected spatial input count along a dimension as a splitting criteria. The bounding polygons may be minimum bounding rectangles.