Abstract: Systems and methods for performing retransmission of data packets over a network. A node receives a data packet with a source and a destination address. The data packet is sent along a network path to the destination address, and information associated with the data packet is sent to a controller node that is independent of the network path. A controller receives information associated with a data packet from any forwarder node within a plurality of forwarder nodes each monitoring communications along separate communications paths. An indication of a receipt acknowledgement for the data packet is received from a second forwarder node that is separate from the first forwarder node and the controller node. The receipt acknowledgement is correlated with the data packet and based on the correlating, data associated with retransmission processing of the data packet is deleted.

Abstract: Methods for performing retransmission of data packets over a network. A node receives a data packet with a source and a destination address. The data packet is sent along a network path to the destination address, and information associated with the data packet is sent to a controller node that is independent of the network path. A controller receives information associated with a data packet from any forwarder node within a plurality of forwarder nodes each monitoring communications along separate communications paths. An indication of a receipt acknowledgement for the data packet is received from a second forwarder node that is separate from the first forwarder node and the controller node. The receipt acknowledgement is correlated with the data packet and based on the correlating, data associated with retransmission processing of the data packet is deleted.

Abstract: A processor-implemented method, apparatus, and/or computer program product move Open Systems Interconnection (OSI) layer 4 connections between wirelessly-connected user equipment to a series of cell-towers, wherein an OSI layer 4 connection is extracted out of the underlying cellular protocols at the series of cell-towers. A detection is made that user equipment, which has a broken-out layer 4 connection, has moved from a first cell-tower to a second cell-tower. Traffic for an existing layer 4 connection from the user equipment is tunnelled between the first cell-tower and the second cell-tower. A predetermined trigger event is identified. In response to the predetermined trigger event occurring, an ongoing bidirectional flow of data packets is migrated from the user equipment over to layer 4 connections maintained at the second cell-tower.

Abstract: Traffic redirection methods include determining a quality-affective factor in a connection between a client and a server in a network; comparing the quality-affective factor to a threshold to determine whether the connection would benefit from a network processing function; reconfiguring the network to redirect the connection to or away from a middlebox that performs the network processing function in accordance with the determination of whether the connection would benefit from the network processing function.

Abstract: Dynamic middleboxes include a network monitor module configured to determine a quality-affective factor in a connection between a client and a server in a network; a processor configured to compare the quality-affective factor to a threshold to determine whether the connection would benefit from a network processing function; and a network control module configured to reconfigure the network to redirect the connection to a middlebox that performs the network processing function if the connection would benefit and further configured to reconfigure the network to exclude the middlebox from the connection if the connection would not benefit.

Abstract: There are provided a transparent performance enhancing proxy, a method for operating a transparent performance enhancing proxy between a source device and a destination device, and corresponding computer program product. The method includes preserving, without translation, packet header information of a header for a packet received from the source device to be forwarded to the destination device. The method further includes during a transmission control protocol connection setup phase for the packet, preserving transmission control protocol connection semantics. The method also includes during a transmission control protocol data transfer phase for the packet, running a transmission control protocol by masquerading as the source device to the destination device and masquerading as the destination device to the source device to transmit the packet to the destination device with the preserved packet header information.

Abstract: There are provided a transparent performance enhancing proxy, a method for operating a transparent performance enhancing proxy between a source device and a destination device, and corresponding computer program product. The method includes preserving, without translation, packet header information of a header for a packet received from the source device to be forwarded to the destination device. The method further includes during a transmission control protocol connection setup phase for the packet, preserving transmission control protocol connection semantics. The method also includes during a transmission control protocol data transfer phase for the packet, running a transmission control protocol by masquerading as the source device to the destination device and masquerading as the destination device to the source device to transmit the packet to the destination device with the preserved packet header information.

Abstract: Techniques for managing network traffic in a virtual consolidated appliance so as to avoid interruptions in existing network connections during reconfiguration of the virtual consolidated appliance are provided. In one aspect, a method for operating a virtual consolidated appliance having a plurality of servers is provided. The method includes the following steps. An assignment for load balancing is computed based on a status of the virtual consolidated appliance. A reconfiguration of the virtual consolidated appliance is discovered. A new assignment is computed for load balancing based on a new status of the virtual consolidated appliance based on the reconfiguration of the virtual consolidated appliance. Existing network connections are redirected according to the assignment during the reconfiguration of the virtual consolidated appliance. New network connections are served according to the new assignment.

Abstract: A snoop method for increasing the efficiency of TCP protocol operations at the snoop receiver by assuming there is no reordering over the wireless hop. The method performs maintaining a copy of each packet received, the copy adapted for retransmission to the receiver device on behalf of the source device and maintaining for each packet received, a virtual send time (VST) value of that packet. The VST corresponds to a virtual time the packet was sent or retransmitted to the receiver device. There is further maintained an estimate of the receiver device's time (VRT) based on acknowledgement (ACK) messages for packets received from the receiver device. Responsive to receiving an acknowledgement for a packet sent at the time VST, the method infers any lost packets and retransmits a copy of any lost packets having a VST value sent before the receiver's VRT estimate.

Abstract: Middleboxes include a processor configured to determine that a network connection between a client device and a server device is idle. A connection table is configured to create a first connection entry at the middlebox for the client device and a second connection entry at the middlebox for the server device. The first and second connection entries are initialized after determining that the network connection between the client device and the server device is idle. A network control module is configured to activate redirection of the network connection between the client device and the server device to the middlebox after determining that the network connection between the client device and the server device is idle.

Abstract: A snoop receiver, method and computer program product for increasing the efficiency of TCP protocol operations at the snoop receiver by assuming there is no reordering over the wireless hop. The method performs maintaining a copy of each packet received, the copy adapted for retransmission to the receiver device on behalf of the source device and maintaining for each packet received, a virtual send time (VST) value of that packet. The VST corresponds to a virtual time the packet was sent or retransmitted to the receiver device. There is further maintained an estimate of the receiver device's time (VRT) based on acknowledgement (ACK) messages for packets received from the receiver device. Responsive to receiving an acknowledgement for a packet sent at the time VST, the method infers any lost packets and retransmits a copy of any lost packets having a VST value sent before the receiver's VRT estimate.

Abstract: Middlebox systems that can enter a connection include a monitoring module to monitor information in a connection between a client and a server, a processor to determine that the connection is idle, a table configured to create a first entry for the client and a second entry for the server, where the entries are initialized using information gathered by the monitoring module, and a control module to redirect the connection between the client and server to the middlebox. Middlebox systems that can exit a connection include a processor to determine a mismatch between sequence numbers in a first connection to a client device and in a second connection to a server device. A network control module delays acknowledgment signals from the middlebox on a connection to decrease the degree of mismatch and establishes a direct connection between the client device and the server device when mismatch is zero.

Abstract: There are provided a transparent performance enhancing proxy, a method for operating a transparent performance enhancing proxy between a source device and a destination device, and corresponding computer program product. The method includes preserving, without translation, packet header information of a header for a packet received from the source device to be forwarded to the destination device. The method further includes during a transmission control protocol connection setup phase for the packet, preserving transmission control protocol connection semantics. The method also includes during a transmission control protocol data transfer phase for the packet, running a transmission control protocol by masquerading as the source device to the destination device and masquerading as the destination device to the source device to transmit the packet to the destination device with the preserved packet header information.

Abstract: Disclosed is a novel passive fingerprinting technique based on DHCP messages to determine the device type and operating system. DHCP implementations are shown to vary among device types and have an effect on DHCP lease durations. To improve network address utilization, without introducing any protocol changes, the present invention provides a new leasing strategy which takes into account device types. This strategy, compared to current approaches, improves the address utilization sixfold without considerably increasing DHCP overhead.

Abstract: Methods for inserting a middlebox into a network connection include monitoring network state information in a connection between a client and a server. When the connection is idle, a connection entry is created for each device and is initialized using state information gathered by monitoring the network connection. Redirection of the network connection is activated between the client and the server such that the middlebox mediates the connection. Methods for removing a middlebox from a network connection include determining a degree of mismatch between a sequence number in a first connection between the middlebox and a client and a sequence number in a second connection between the middlebox and a server, delaying acknowledgment signals from the middlebox on a connection to decrease the degree of mismatch, and establishing a direct connection between the client and the server without mediation by the middlebox when the degree of mismatch is zero.

Abstract: Methods for inserting a middlebox into a network connection include monitoring network state information in a connection between a client and a server. When the connection is idle, a connection entry is created for each device and is initialized using state information gathered by monitoring the network connection. Redirection of the network connection is activated between the client and the server such that the middlebox mediates the connection. Methods for removing a middlebox from a network connection include determining a degree of mismatch between a sequence number in a first connection between the middlebox and a client and a sequence number in a second connection between the middlebox and a server, delaying acknowledgment signals from the middlebox on a connection to decrease the degree of mismatch, and establishing a direct connection between the client and the server without mediation by the middlebox when the degree of mismatch is zero.

Abstract: Techniques are disclosed for load balancing in networks such as those networks handling telephony applications. By way of example, such techniques direct requests associated with calls to servers in a system comprised of a network routing calls between a plurality of callers and at least one receiver wherein a load balancer sends requests associated with calls to a plurality of servers as follows. A request associated with a call, a caller, or a receiver is received, depending on the particular load balancing technique. A server is selected to receive the request. A subsequent request is received. A determination is made whether or not the subsequent request is associated with the call, the caller, or the receiver, depending on the particular load balancing technique. The subsequent request is sent to the server based on determining that the subsequent request is associated with the call, the caller, or the receiver, again depending on the particular load balancing technique.

Abstract: A network switching system and method and a computer program product for operating a network switch are disclosed. The network switch includes a multitude of input ports and a multitude of output ports. In one embodiment, one processing device is assigned to each of the input ports and output ports to process data packets received at the input ports and transferred to the output ports. In one embodiment, the method comprises creating an intermediate adjustable configuration of processing devices functionally between the input ports and the output ports, and assigning the processing devices of the intermediate configuration to forward the data packets from the input ports to the output ports to obtain a balance between latency and synchronization of the transfer of the data packets from the input ports to the output ports. In an embodiment, software is used to create and to adjust dynamically the intermediate configuration.

Abstract: In a computer system comprising a plurality of computing devices wherein the plurality of computing devices processes a plurality of tasks and each task has a task type, a method for determining overheads associated with task types comprises the following steps. Overheads are estimated for a plurality of task types. One of the plurality of computing devices is selected to execute one of the plurality of tasks, wherein the selection comprises estimating load on at least a portion of the plurality of computing devices from tasks assigned to at least a portion of the plurality of computing devices and the estimates of overheads of the plurality of task types. One or more of the estimates of overheads of the plurality of task types are varied.

Abstract: Techniques are provided for dynamically scheduling requests in data processing systems in accordance with differentiated service levels. In a first aspect of the invention, a technique for processing a request to at least one server comprises the following steps. A request is received. Then, submission of the request to the at least one server is scheduled based on: (i) a quality-of-service (QoS) class assigned to a client from which the request originated; (ii) a response target associated with the QoS class; and (iii) an estimated response time associated with the at least one server. The technique may further comprise the step of withholding the request from submission to the at least one server when the request originated from a client assigned to a first QoS class to allow a request that originated from a client assigned to a second QoS class to meet a response target associated therewith.