Abstract: Systems and methods are provided for determining an optical bypass for an inter-regional wide area network (WAN) for regions of server facilities of a cloud service provider. In particular, the optical bypass connects non-adjacent regional server centers of the WAN by eliminating needs of data conversions at intermediate regional server centers. The determining the optical bypass includes receiving a WAN topology data, capacity and demand information about the WAN. The determining includes an objective function to maximize a number of network resources to free up by determining a revised data flow and bandwidth allocations by introducing the optical bypass in the WAN. The disclosed technology transmits the determined data traffic flow and resource allocation information of the optical bypass, causing a network traffic enforcers to reconfigure the WAN.

Abstract: Systems and methods are provided for determining an optical bypass for an inter-regional wide area network (WAN) for regions of server facilities of a cloud service provider. In particular, the optical bypass connects non-adjacent regional server centers of the WAN by eliminating needs of data conversions at intermediate regional server centers. The determining the optical bypass includes receiving a WAN topology data, capacity and demand information about the WAN. The determining includes an objective function to maximize a number of network resources to free up by determining a revised data flow and bandwidth allocations by introducing the optical bypass in the WAN. The disclosed technology transmits the determined data traffic flow and resource allocation information of the optical bypass, causing a network traffic enforcers to reconfigure the WAN.

Abstract: Systems and methods are provided for determining an optical bypass for an inter-regional wide area network (WAN) for regions of server facilities of a cloud service provider. In particular, the optical bypass connects non-adjacent regional server centers of the WAN by eliminating needs of data conversions at intermediate regional server centers. The determining the optical bypass includes receiving a WAN topology data, capacity and demand information about the WAN. The determining includes an objective function to maximize a number of network resources to free up by determining a revised data flow and bandwidth allocations by introducing the optical bypass in the WAN. The disclosed technology transmits the determined data traffic flow and resource allocation information of the optical bypass, causing a network traffic enforcers to reconfigure the WAN.

Abstract: A method for automatically analyzing formulas and adding pattern annotations to quantifiers based on a database of common pattern idioms. The method involves matching base pattern inference for Satisfiability Modulo Theories (SMT) solvers. The method uses a database for fault detection in externally supplied pattern annotated formulas. The method also uses matching code trees to mixed second-order pattern matching.

Abstract: A system is described that analyzes and validates network security policies associated with network devices. The system includes a compiler and a security policy analysis and validation tool. The compiler encodes a security policy associated with a network device into a predicate expressed in bit-vector logic and generates a bit-vector formula based on the predicate. The tool receives the bit-vector formula and applies a Satisfiability Modulo Theories (SMT) solver thereto to identify and enumerate solutions to the bit-vector formula. The enumerated solutions provide information about the validity of the first security policy. The solutions may be compactly enumerated in a as product of intervals or a product of unions of intervals.

Abstract: A system is described that analyzes and validates network security policies associated with network devices. The system includes a compiler and a security policy analysis and validation tool. The compiler encodes a security policy associated with a network device into a predicate expressed in bit-vector logic and generates a bit-vector formula based on the predicate. The tool receives the bit-vector formula and applies a Satisfiability Modulo Theories (SMT) solver thereto to identify and enumerate solutions to the bit-vector formula. The enumerated solutions provide information about the validity of the first security policy. The solutions may be compactly enumerated in a as product of intervals or a product of unions of intervals.

Abstract: Systems and methods for compression of data to be transmitted are described. A data stream, such as a byte code sequence, is partitioned into one or more data chunks. The data chunks can be associated with an identifier, such as a signature that differentiates one data chunk from the other. Thus, different data chunks would be identifiable through different signatures. The data chunks associated with the signatures can be compared with a repository or a history buffer. The history buffer includes a collection of previously transmitted data chunks each associated with their respective signature.

Abstract: A design space exploration (DSE) system automatically discovers viable solutions within a design space. The DSE system operates by creating or receiving a design specification that is described using a design language. The design specification contains a collection of constraints that an acceptable architecture is expected to satisfy. The DSE system then symbolically executes the design specification to provide a logical formula. The DSE system then interacts with a theorem prover module to identify one or more solutions to the formula. Finally, the DSE system converts the solutions into a user-interpretable form (e.g., expressed in the format of the modeling language) for viewing by a user. Each solution pertains to an architecture that satisfies the collection of constraints. The DSE system ensures that the solutions are diverse by disfavoring any solution that is deemed similar to any solution that has been previously encountered.

Abstract: An extension of symbolic execution for programs involving contracts with quantifiers over large and potentially unbounded domains is described. Symbolic execution is used to generate, from a program, concrete test cases that exhibit mismatches between the program code and its contracts with quantifiers. Quantifiers are instantiated using symbolic values encountered during a set of exhibited runs. In this setting, quantifier instantiation is limited to values supplied to or produced by a symbolic execution. Quantifier instantiation is controlled by performing a matching algorithm that uses run-time values of input and program variables in order to guide and limit the set of quantifier instantiations. With a sufficient set of instances, test cases are derived that directly witness limitations of the auxiliary assertions.

Abstract: The present invention provides a method for chunking an object. The method is arranged to provide efficient chunking of objects such that objects can be efficiently updated between a remote machine and a local machine over a network. The chunking algorithm is applicable in networked application such as file synchronization using remote differential compression (RDC) techniques. The chunking algorithm provides enhanced efficiencies by locating chunk boundaries around local maxima.

Abstract: Embodiments are introduced which provide for creation of an E-matching code tree index which works on E-graphs to make E-matching more efficient. Use of the E-matching code tree allows performing matching of several patterns simultaneously. Embodiments are also described which provide for the generation of inverted path indexes. An inverted path index may be used to filter an E-graph to determine terms which may potentially match patterns when an E-graph is updated.

Abstract: A design space exploration (DSE) system automatically discovers viable solutions within a design space. The DSE system operates by creating or receiving a design specification that is described using a design language. The design specification contains a collection of constraints that an acceptable architecture is expected to satisfy. The DSE system then symbolically executes the design specification to provide a logical formula. The DSE system then interacts with a theorem prover module to identify one or more solutions to the formula. Finally, the DSE system converts the solutions into a user-interpretable form (e.g., expressed in the format of the modeling language) for viewing by a user. Each solution pertains to an architecture that satisfies the collection of constraints. The DSE system ensures that the solutions are diverse by disfavoring any solution that is deemed similar to any solution that has been previously encountered.

Abstract: A method is described for combining models of a plurality of theory solvers in order to produce a model which may be satisfiable by each of the plurality of theory solvers. A model is accessed for a first theory solver which is satisfiable in the first theory solver. It is determined that one or more equalities are implied by the model and it is determined if the equalities are compatible with a second solver. The model is updated in accordance any equalities determined not to be compatible with the second solver. A method is also described for mutation of models using freedom intervals. A freedom interval is determined for a variable within a model and the model is updates by choosing a value for the variable which lies within the freedom interval.

Abstract: Aspects of the subject matter described herein relate to resource replication systems. In aspects, a mechanism is described that detects when local resources are stale. Local resources may be stale when the time between a last successful synchronization activity and a current time exceeds a staleness value. If the local resources are determined to be stale, the local member may refrain from certain synchronization activities until the local member is allowed to resume these certain synchronization activities. If the local resources are not stale, additional synchronization activities including synchronizing resources between the member and an upstream or downstream partner may be performed.

Abstract: Various embodiments introduce the notion of a replication entity which implements a highly scalable file replication system. In one embodiment, the replication entity resides in the form of a scalable replication service. In at least some embodiments, the replication service provides a “drive in the sky” facility that can be used by individuals, such as subscribers, to synchronize their individual machines, such that their files are automatically replicated to a safe and always-on location. Alternatively or additionally, individuals such as subscribers can also access their files via a web-based interface when they are away from their machines.

Abstract: Peer devices register with a resource locator service so that the peer devices can be uniquely identified in a networking environment. An addressing scheme addresses a peer resource in the networking environment based on the unique identifier of a peer device that is a master publisher of the resource. Based on the addressing scheme, the resource locator service can track the location of the master publisher of the resource as well as additional locations of peer devices that have cached the resource and made it available. In various embodiments, the resource locator service can service requests for peer resources by providing a list of locations where the resource is expected to be available or, in the case of non-compatible requester, provide access to the resource itself.

Abstract: An extension of symbolic execution for programs involving contracts with quantifiers over large and potentially unbounded domains is described. Symbolic execution is used to generate, from a program, concrete test cases that exhibit mismatches between the program code and its contracts with quantifiers. Quantifiers are instantiated using symbolic values encountered during a set of exhibited runs. In this setting, quantifier instantiation is limited to values supplied to or produced by a symbolic execution. Quantifier instantiation is controlled by performing a matching algorithm that uses run-time values of input and program variables in order to guide and limit the set of quantifier instantiations. With a sufficient set of instances, test cases are derived that directly witness limitations of the auxiliary assertions.

Abstract: A method and system for controlling which content gets precedence and is replicated. A replica set is comprised of a set of resources. Each resource is associated with resource data and resource meta-data. For files-based systems, resource data includes file contents and attributes, while resource meta-data includes additional attributes that are relevant for negotiating synchronization during replication. An extra field called a “fence value” is added to the meta-data associated with each resource. During synchronization, first fence values are compared. The resource with the highest fence value includes the content that is controlling and replicated. If fence values are equal (and greater than a particular value), the controlling resource is determined based on other meta-data.

Abstract: A method for automatically analyzing formulas and adding pattern annotations to quantifiers based on a database of common pattern idioms. The method involves matching base pattern inference for Satisfiability Modulo Theories (SMT) solvers. The method uses a database for fault detection in externally supplied pattern annotated formulas. The method also uses matching code trees to mixed second-order pattern matching.

Abstract: Remote differential compression is integrated within applications. Objects are updated between two or more computing devices using remote differential compression (RDC) techniques such that required data transfers are minimized. An algorithm provides enhanced efficiencies for allowing the receiver to locate a set of objects that are similar to the object that needs to be transferred from the sender. Once this set of similar objects has been found, the receiver may reuse any chunks from these objects during the RDC algorithm.