322 results about "Maximum transmission unit" patented technology

The present invention provides a method and apparatus for discovering a path maximum transmission unit. The method comprises receiving a data packet from a first remote device for transmission to a second remote device and determining if a size of the received data packet is greater than a maximum transmission unit (MTU) value. In response to determining that the size of the received data packet is greater than the MTU value, the method further comprises transmitting a portion of the received data packet to the second remote device and transmitting a message to the first remote device indicating that the size of the received data packet exceeds the MTU value.

A method for network communication and an apparatus for discovery of a maximum transmission unit (MTU) size in a path between two nodes of a network are disclosed. A plurality of test packets of varying transmission unit (TU) size may be sent from the first host to the second host. A “do not fragment” (DF) flag for the test packets is not set. It is determined whether one or more of the test packets were received by the second host. An estimated path MTU for a network path between the first and second hosts size may then be calculated based on one or more patterns of receipt of the test packets by the second host. Once the estimated Path MTU size has been determined, message packets of a size less than or equal to the Path MTU size may be sent over the network path.

Network endpoints using TCP/IP operate to determine the maximum transmission unit (MTU) of the path between them. This determination is done so as to avoid the expensive IP fragmentation that will occur when transitting links with a smaller MTU size. The standard method of determining the path MTU (PMTU) has several known deficiencies, including: inefficient use of bandwidth as proper operation will likely result in the loss of one or more packets and difficulty of implementation as the reverse channel communication mechanism, reception of ICMP messages indicating the discarding of unfragmentable packets, is frequently blocked by firewalls and other security apparatus. A method of determining the PMTU between intermediate proxies is disclosed that does not require reception of ICMP messages or the inefficient use of bandwidth due to the presumed dropping of packets with valid data.

A network processing apparatus is provided. A send buffer receives from a protocol stack a long packet with a data length exceeding a maximum transmission unit defined for a network and stores the long packet. A payload dividing unit divides the payload of the long packet into a plurality of divided payloads. A header duplicating unit duplicates the header of the long packet so as to generate a duplicated header for the respective divided payload. A short packet generating unit attaches the duplicated header to the respective divided payload so as to generate a short packet with a data length equal to or less than the maximum transmission unit to be sent to the network. A sending unit sends the short packet to the network via a physical interface.

A method and system for transmitting information between a sending means and a receiving means using packets for information transmission. The receipt of transmitted packets is acknowledged and unacknowledged packets are retransmitted from the sending means. The amount of transmitted unacknowledged information or the number of consecutive unacknowledged packets is detected, and the reason for information or packet loss is determined based on the amount of transmitted unacknowledged information or the number of consecutive unacknowledged packets. This amount is compared with a path maximum transmission unit (PMTU) to determine the reason for loss. A single or small number of unacknowledged packets is determined to be a result of Bit Error Rate (BER), whereas a larger number of consecutive unacknowledged packets may be determined to be congestion. Congestion control parameters are kept unchanged when the reason for loss is caused by Bit Error Rate (BER), whereas control parameters are changed when the reason for loss is congestion.

In a multinode data processing system in which the nodes communicate with one another through communication adapters coupled to a switch or network, a method is provided for using the Internet Protocol (IP) for transmitting large broadcast data packets without incurring the overhead normally associated with packet fragmentation. By adding an Internet Protocol (IP) header as the first header in every packet fragment in the fragmentation process, fragmented packets are able to be assembled in the IP layer without intervention at the adapter interface layer.

The invention embodiment discloses a method and a device for forwarding a data frame based on line bundle. The method for forwarding the data frame based on line bundle comprises the following steps: acquiring a first data frame transmitted by a user side or a network side; dividing the first data frame when the first data frame is greater than the maximum transmission unit MTU of any access linebundled to the user, wherein the sub data frames obtained from division are all less than or equal to the MTU; adding logical identifiers corresponding to the access line bundled to the user to the sub data frames; and transmitting a second data frame comprising the sub data frames and the logical identifiers of the sub data frames so that the data frame can be reformed after being received at anopposite end. The method and the device for forwarding the data frame based on the line bundle increase the bandwidth of the access line, prolong the transmission distance and improve the transmission reliability on the basis of ensuring the transmission quality of the access line.

A method, system and computer program product for creating dynamic custom headers and for controlling flow rate of Downstream External Physical layer Interface (DEPI) packets are described herein. The method comprises concatenating or fragmenting a packet descriptor of a DEPU packet based on one or more of associated packet size, maximum transmission unit, packet type, channel configuration information and flow control mode. The method further comprises creating a header for the packet based on data in a programmable header template and storing the header in a header buffer, determining whether to transmit the packet based on one of a flow meter or a maximum transmission unit size and transmitting the packet by sending the packet descriptor to an output direct memory access (DMA) controller. A flow meter flow control mode determines if a packet is to be transmitted based on packet size, bucket size, a low threshold and a high threshold. A maximum transmission unit flow control mode determines if a packet is to transmitted based on packet size and a maximum transmission unit size. The header can be customized for Packet Streaming Protocol (PSP) mode or Moving Picture Experts Group Transport Stream (MPT) mode and includes dynamic customizable fields such as User Datagram Protocol (UDP) port identification, flow identification and session identification.

A technique for encapsulating data packets at a Data Link Layer to provide security functions. The technique first encrypts a payload to provide an encrypted payload. The encrypted payload is inserted in an output encapsulated frame. Also added to the output encapsulated frame is an encapsulation header that includes security information, such as a security packet index (SPI) value used to identify a security association (SA). Because the output encapsulated frame may now be longer than maximum allowed Ethernet Path Maximum Transmission Unit (PMTU), the encapsulation header also preferably includes a fragmentation field. The fragmentation field supports the ability to fragment the encrypted datagrams into smaller pieces.

A method and mechanism for determining when to transmit a probe packet to detect increases in path maximum transmission unit (PMTU) in a network having a host and a target interconnected by the network. Calculate a utility variable corresponding to a number of packets to be transmitted from the host to the target which are greater than a predetermined amount of a known PMTU for the target. When the utility variable is greater than a predetermined utility threshold, sending instructions to the host to send a probe packet to detect increases in PMTU for the target. Storing the previous state of the internet path with respect to PMTU in a variable PPMTU and tracking it during decreases so that a restoration of the PMTU can be verified by sending probes. PMTU is treated as a resource which is either fully or partially used by an application.

The invention relates to an intelligent efficient video/audio data transmission method adapted to different network environments, which comprises the following steps of: adjusting the data in real time according to a network state, and when a network packet loss rate is more than a threshold value, adopting a UPD protocol of a path maximum transmission unit to transmit the data; when the network packet loss rate is less than the threshold value and a network delay is more than the threshold value, adopting a TCP+UPD protocol to transmit the data; and when both the network delay and the network packet loss rate are less than the threshold value, adopting a TCP protocol to transmit the data. A layered design is adopted, namely, a binary transmission layer packages all the network transmission details; and a video and audio transmission layer is packaged on the binary transmission layer; all the logics correlated with video and audio are realized in the video and audio transmission layer. Therefore, a caller can realize the transmission of frame levels of the video and audio of a file by only appointing the media file required to be transmitted so as to greatly simplify the use of the superior caller; and a video and audio service intelligently selects a transmission strategy to finish the real-time transmission of video and audio data and to obtain efficient transmission performance according to the real-time characteristics of a network.

The invention relates to a method for detecting the maximum transmission unit of path, which is characterized in that: each middle node of node chain from the force source node to the target node, should process the data report of maximum transmission unit of the detecting path sent from the source node to the target node; when the middle node receives the data report, to display the maximum transmission unit information in said data report; and when the target node receives the data report, sending the maximum transmission unit information to the source node; and the source node, based on received information, confirms the path maximum transmission unit of the chain from it to the target node. The invention can quickly and accurately confirm PMTU, to confirm the best throughout of network, and avoid loss and retransmission, to improve the network safety.

Systems and methods of propagating maximum segment size and path maximum transmission unit of network paths between an intermediary device of a cluster with a plurality of destinations are described. A first core of a node including multiple cores and intermediary to a client and a plurality of servers may receive a response to a packet transmitted to a destination indicating that the packet has a size greater than a MTU of a network path between the node and a destination. The first core identifies the MTU of the network path and determines that the identified MTU is different than an MTU used by the first core. The first core replaces the MTU stored in an entry corresponding to the destination in a PMTU table maintained with the identified MTU. The first core transmits, to other cores of the node, the identified MTU to update each core's PMTU table.

The invention discloses a data transmission method, a transmitting end, a receiving end and a data transmission system and belongs to the communication technical field. The data transmission method includes the following steps that: data to be transmitted are segmented divided into a plurality of data packets according to a preset data unit, and the data packets are numbered consecutively, and the size of the preset data unit is smaller than a largest transmission unit; the transmitting end transmits the data packets to the receiving end sequentially; the receiving end receives the data packets transmitted by the transmitting end and judges whether packet loss occurs according to the continuity of the serial numbers of the received data packets, and feeds back packet loss information to the transmitting end according to a preset period; and the transmitting end retransmits lost data packets to the receiving end according to the packet loss information until the receiving end successfully receives all the data packets or the transmitting time of the data packets reaches preset time. The data transmission method, transmitting end, receiving end and data transmission system of the invention have the advantages of high data transmission speed and high reliability.

A method, system, and computer program product for optimizing a message size for communication in a communication network are disclosed. The method comprises identifying a connection to a target, sending to a path maximum transmission unit value server (which is not the target) a request for a path maximum transmission unit value for the connection to the target, and, in response to receiving the path maximum transmission unit value for the connection to the target from the server, optimizing a communication by sending to the target a packet having a size in accordance with the value.

The invention discloses a message fragment sending method, device and network equipment. The method comprises the following steps: processing a message transferred from a transmission layer at an IP (Internet protocol) layer, wherein fragmentation operation is avoided from being carried out on the message in the processing process; processing the message processed at the IP layer at a data link layer, and delivering the message to a communication interface sending the message; comparing the length value of the message processed at the data link layer with a value of the MTU (maximum transmission unit) of the interface; and if the length value is greater than the value of the MTU, fragmenting the message processed at the data link layer according to the value of the MTU and sending through the communication interface. Compared with the prior art, the invention has the advantages that the flow of fragmenting and sending a relatively long message is simplified, and the problem that the system performance is influenced due to the excessive occupation of a CPU (central processing unit) and storage bandwidth by the fragments at the IP layer is avoided.

A method for efficiently determining the path maximum transmission unit (MTU) during a handshake between a source host and a target host across a computer network. During the handshake, each router receives the SYN (synchronization) packet transmitted from the source host, and each router updates the value of the path MTU within the SYN packet when the path MTU value is greater than the MTU of the router. When the SYN packet reaches the target host, the target host also updates the value of the path MTU if the value of the path MTU within the SYN packet is greater than that of the target host. With this sequential checking and updating of the path MTU against their MTUs, the combination of the routers en-route and the target host ensures that the final path MTU is equal to or smaller than the smallest MTU of the various components/networks along the path.

A solution for tunnel path MTU discovery includes, at a first network device configured as an origination endpoint for a tunnel, storing a keep-alive packet having a size of an interface maximum transmission unit (MTU), the keep-alive packet indicating the packet should not be fragmented, the second network device configured as a termination endpoint for the tunnel. If the sending fails, the size of the keep-alive packet is iteratively changed to converge upon a path MTU, where the path MTU is the size of a largest keep-alive packet that can be sent from the first network device to the second network device without fragmentation.

The invention relates to a method for reducing the number of data IP fragments in packet domain network, and its kernel: packet network device regulates MSS parameter value of maximum transfer unit carried in TCP connection information between terminal and service according to the set MSS parameter threshold and sends out the regulated TCP connection information; the terminal or server learns a longest message segment length supported by the opposite terminal through MSS parameter carried in the TCP connection information, and compares this longest message segment length with its own longest message segment length, and selects the smaller value to make segment handling on TCP transfer data. And the invention can reduce IP packet fragments between packet network devices by regulating MSS parameter value, reduce data packet handling delay and improve packet device handling ability.

The invention provides a Bluetooth low-power-consumption communication method, Bluetooth equipment and a system. The method is applied to communication among the Bluetooth equipment. The method comprises the following steps: acquiring the maximum transmission unit value of second Bluetooth equipment by using first Bluetooth equipment, judging whether the size of data to be transmitted is greater than a transmission reference value which is a smaller one in the maximum transmission unit value of the second Bluetooth equipment and the maximum transmission unit value of the first Bluetooth equipment during transmission of data from the first Bluetooth equipment to the second Bluetooth equipment, and if not, directly transmitting the data to be transmitted; and otherwise, partitioning the data to be transmitted into data blocks, wherein circularly transmitting the partitioned data blocks, wherein the size of each partitioned data block is smaller than or equal to the transmission reference value. By adopting the Bluetooth low-power-consumption communication method, the Bluetooth equipment and the system, the influence of failure in receiving of the second Bluetooth equipment due to an overlarge transmission value on the transmission speed is eliminated; or prolonging of the transmission time due to transmission of an excessively small value is avoided, and the Bluetooth low-power-consumption communication speed is increased.

The present invention provides a method and system for the identification and discovery of the lowest maximum transmission unit (MTU) size for transmission packets on some or all of the transmission path nodes. Different methods and protocols are described in the present patent application to support the identification and discovery of the lowest maximum transmission unit (MTU) size for fragmented transmission packets.

The invention provides a method for adjusting the Path Maximum Transmission Unit (PMTU), which includes the following steps: an intermediate node whose MTU value is changed transmits notification message to a source node; after the source node receives the notification message, the source node initiates the PMTU detection and renews the PMTU value according to the detection result. In addition, the invention also provides a notification alternation method of MTU, a notification alternation device of MTU and a PMTU adjustment device. By using the technical proposal of the invention, the source node can adjust timely the PMTU value according to the changes of MTU value of the intermediate node, reduce the occurrences of packet loss, improve the utilization rate of network resources, increase the network throughput and the performance of network links.

An information handling system is provided. The information handling system includes a plurality of network devices. One of the plurality of network devices is a source device and another of the plurality of network devices is a destination device. If path maximum transmission unit (PMTU) information for a path between the source device and the destination device is not known, the source device sends a PMTU send packet to the destination device, and the destination device sends a PMTU receive packet with a received PMTU value to the source device. Other associated systems and methods for PMTU discovery are also provided.

The invention relates to a processing method of disordered fragmentation messages in an SDN (software defined network) and an application. The processing method comprises the following steps of: issuing PMTU (path maximum transmission unit) 'PathMTU' of a forwarding path and a fragmentation rule, adding stream ids (identities) to messages entering streams of the SDN, determining the belonging streams of the fragmentation messages encountered in the SDN, and forwarding the fragmentation messages according to the streams.