Abstract: A method and system for transmitting packets having a first address length on a core network supporting a second address length, where the second address length is larger than the first address length by determining a length of the first address and establishing an offset to the first address such that a combined length of the offset, length of a network prefix for the second address and length of the first address equals the length of the second address. The method and system of the present invention can be implemented as an enhancement to existing network protocols such as IPv4, IPv6 and the like.

Abstract: In one embodiment, a received data packet is delivered by a routing resource to a tunnel interface resource in response to determining that the received data packet specifies a destination address starting with a prescribed aggregation prefix. The tunnel interface resource computes a home address for a mobile router based on a second address prefix from a start of the destination address, the second address prefix within the prescribed aggregation prefix and having been assigned as reachable by the mobile router, at least a portion of the second address prefix applied to a prescribed mapping function. The tunnel interface resource determines a care-of address for reaching the mobile router based on the corresponding home address calculated by the tunnel interface resource, and encapsulates the received data packet into an encapsulated packet having a destination address field specifying the care-of address, for output of the encapsulated packet toward the mobile router.

Abstract: A data transfer control device includes a link controller which analyzes a packet received from a host-side data transfer control device through a serial bus, and an interface circuit which generates an interface signal and outputs the generated interface signal to an interface bus. When the address automatic update mode in an address automatic update field of a packet received from the host-side data transfer control device is set to ON, the interface circuit sequentially outputs signals of automatically updated addresses and signals of L-bit-data from among K bits of data set in the packet, the L-bit-data making a pair with each of the automatically updated addresses, while performing address automatic update processing M times (K=L×(M+1)) using an address set in the packet as a start address.

Abstract: Methods, apparatus and computer readable code for compression, encoding and decoding of units of data such as packets are disclosed. In some embodiments, methods, apparatus and computer readable code for transmitting and/or receiving the data packets (for example, transmitting from a sending location to a receiving location where packets are received) are provided. For at least some packets, a dictionary is determined from a respective group of packets, including a first set of historical packets and excluding a second set of historical packet. Each target packet is encoded and/or compressed and/or decoded using the respective dictionary. Optionally, the respective group of packet includes the actual target packet to be encoded and/or compressed and/or decoded.

Abstract: A communication control device comprises a calculation part for calculating the number of frames and the frame length for transmitting the transmit data, a payload division part for dividing the transmit data into frame units based on the calculation results of the calculation part, and a header generation part for generating a header to be appended to the transmit data of frame unit based on the calculation results of the calculation part in the midst of dividing the transmit data by the payload division part. Thereby, the parallel processing ability of the hardware can be exhibited, a memory management method can be simplified, and the transmit data can be outputted as the frame at high speed.

Abstract: A method for bidirectional data transmission of a data set between a data transmission device and a data reception device via at least one packet-oriented network device, which includes encapsulation of the data set to enable a connection-oriented data transmission of the data set; connection-oriented transmission of the encapsulated data set by means of at least one telecommunications device from the data transmission device to the packet-oriented network device; evaluation of the data encapsulation protocol in the packet-oriented network device for an unpacking of the data set to enable a packet-oriented data transmission of the data set; and packet-oriented transmission of the data set from the packet-oriented network device to the data reception device.

Abstract: A high performance computer system has a number of compute nodes interconnected by an inter-node communication network. Each compute node has a local packetized interconnect coupled to the inter-node communication network by an interface. Data packets on the local packetized interconnect of a sending node may be delivered to a destination in a receiving node by addressing them to addresses associated with the network interface and tunneling the packets through the inter-node communication network to the receiving node.

Abstract: An apparatus and method are provided for extracting connection information from a traffic header in a communications network. The apparatus includes a first storage element containing a first look-up table for determining a first data packet header offset and data size for extracting a communications protocol type from the header and a second storage element containing a second look-up table for determining from the communications protocol type a second data packet header offset and second data size for extracting a connection address from the header. The storage elements may be in the form of content-addressable memories. Exception handling and hardware initialization can be controlled by a system processor.

Abstract: Example embodiments disclose a prefix assignment device for use in network equipments of an Internet Protocol communication network, the device including a processing module. The processing module of the prefix assignment device may determine a node Nj associated with an unassigned prefix Pj of length L(Pj) equal to L(Rk)?m. The processing module may also assign prefix Pj to the network equipment Rk if m is equal to 0 and/or perform successive m loops if m is greater than 0. The module may select one of the two prefixes with lengths equal to L(Rk) for assignment to the network equipment Rk.

Abstract: A system and method for transmitting a reduced header is presented. A preferred embodiment comprises a base station defining a normal header and a reduced header, wherein the reduced header has a smaller number of bytes than the normal header. The base station then concatenates the reduced header with smaller sized payloads and concatenates the normal header with larger sized payloads.

Abstract: A comprehensive signalling node is provided according to an embodiment of the invention. The comprehensive signalling node includes a signalling interface adapted for transmitting and receiving signalling communications and a storage system configured to store a Media Gateway Controller (MGC) routine, to store a Session Initiation Protocol (SIP) routine, to store a Session Border Controller (SBC) routine, to store a Push-To-Talk (PTT) routine, to store a H.323 routine, to store a Wide Area Network (WAN) compression routine, and to store a Communication Assistance for Law Enforcement (CALE) routine. The comprehensive signalling node further includes a processing system that is configured to receive a signalling communication through the signalling interface, process the signalling communication with the MGC routine if appropriate, with the SIP routine if appropriate, with the SBC routine if appropriate, with the PTT routine if appropriate, with the H.

Abstract: A method of transmitting feedback information is disclosed. More specifically, a mobile station (MS) receives a Protocol Data Unit (PDU) which includes a Medium Access Channel (MAC) header from a base station (BS). Thereafter, the MS determines from the received MAC header whether an extended subheader group appears after the MAC header, and also identifies a feedback request extended subheader from the extended subheader group. Lastly, the MS transmits the feedback information according to the feedback request extended subheader.

Abstract: Stored in the leaf nodes of a data structure that can be used for identifying the longest prefix matching an address are corresponding values from multiple forwarding information bases. A single common address lookup data structure (e.g., a tree, trie, etc.) can be used, and a leaf node can contain information from multiple forwarding information bases. If lookup operations are performed for a single address in multiple forwarding information bases, the single common address lookup data structure may only need to be traversed once. For example, the forwarding information for another forwarding information base may be stored in the same leaf, further down in the data structure requiring traversal from the current position, or above requiring traversal from the root of the lookup data structure. Information can be stored in the leaf node to indicate which traversal option is appropriate for a particular forwarding information base.

Abstract: A method for controlling distribution of network communications (messages). An incoming message either carries priority information, or is assigned priority information based on a shared characteristic with other messages. The priority information is used to determine how and/or when to deliver the message, e.g. by delaying the message for a fixed time. Preferences for receipt of messages by priority level may be communication to upstream hosts along a network path. Accordingly, an intermediary host may reject and/or delay messages that the intended recipient does not wish to receive. This pushes the burden of low-priority messages back to the sender, thereby reducing or eliminating burdens on network/system resources of the recipient and/or intermediaries between the recipient and the sender. Accordingly, it can “squelch” spam messages at or close to their source. Trusted senders complying with prescribed practices may include priority information allowing for delivery of their messages with higher priority.

Abstract: An overlay network and scheme for building and using the overlay network are described. As the overlay network is built, new nodes joining the network are connected randomly with other nodes which results in a random graph as the network topology. The network is fully scalable, with each new node providing the same number of network connections for output to other nodes as it consumes when it joins the network. In addition, network coding is implemented at each node to mix packets of data entering each node using random linear functions. The network coding at each node generates new packets that are independent combinations of original data packets entering the node. The new coded packets make the distribution of data to other nodes more efficient and robust.

Abstract: Multiple data transfer requests can be merged and transmitted as a single packet on a packetized bus such as a PCI Express (PCI-E) bus. In one embodiment, requests are combined if they are directed to contiguous address ranges in the same target device. An opportunistic merging procedure is advantageously used that merges a first request with a later request if the first request and the later request are mergeable and are received within a holdoff period that is dynamically determined based on a level of bus activity; otherwise, requests can be transmitted without merging.

Abstract: A method of adding meta-data to document in a content-routed network including a plurality of routers interconnected by links involves adding an encoded meta-tag to the document.

Abstract: A technique for providing data unit concatenation in a shared communications network is disclosed. The technique establishes a distinction between a first address space and a second address space within one or more shared communications networks, such as a wireless local area network, in a telecommunications system. At a transmitter node, data units arriving from one or more source nodes are packaged together if they are intended a network accessible through a receiver and then are transmitted to the receiver node. During the transfer of data units across the telecommunications system, the addressing mechanism will use either source and destination nodes or transmitter and receiver nodes, depending on the address space relevant at the moment of transmission. The technique increases utilization efficiency, because overhead attributed to headers, acknowledgements and interframe gaps is reduced.

Abstract: A kernel data transfer method and system for transmitting multiple packets of data in a single block of data presented by application programs to the kernel's network subsystem for processing in accordance with data transfer parameters set by the application program. The multi-packet transmit system includes logic that allows header information of the multiple packets of data to be generated in a single buffer and appended to a second buffer containing the data packets to be transmitted through the network stack. The multi-data transmit system allows a device driver to amortize the input/output memory management related overhead across a number of packets. With some assistance from the network stack, the device driver needs to only perform the necessary IOMMU operations on two contiguous memory blocks representing the header information and the data payload of multiple packets during each transmit call.

Abstract: A method and apparatus for determining a read address for received data in a communications network employing virtually concatenated payloads is provided. The method and apparatus comprise determining a minimum write address using a plurality of memory elements and using the minimum write address in connection with received read addresses to determine group read addresses.

Abstract: A method and apparatus for performing an in-service upgrade of a switching fabric of a network element is described. Network traffic is denominated in cells as it passes through the network element. Prior to the upgrade, an internal header is provided to direct the communication of a cell through the network element. The internal header has internal routing information to direct the routing of the cell through the switching fabric of the network element. Additional internal routing information compatible with upgraded components of a network element is added to the cells passing through the network element. The additional internal routing information is dependent on the internal routing information previously provided in the internal header, but differs from the internal routing information in that it supports the upgraded components of the network element.

Abstract: An integrated circuit has a hardware decoder that parses a frame to identify a type of encapsulation. The integrated circuit also has a number of hardware parsers, each parser being coupled to the decoder by an enable line. During packet processing, one of the parsers is enabled by the decoder, based on the value which identifies the encapsulation type. The enabled parser retrieves one or more attributes from the frame, depending on the encapsulation. The integrated circuit also has a register, coupled to each parser, to hold the attributes. The integrated circuit also has a key generation hardware which creates a key, by concatenating from the attributes register, certain attributes that are pre-selected by a user for forming the key. The integrated circuit uses the key to look up in memory a set of user-specified actions that are then performed on data in the frame.

Abstract: Data mirroring in a service such as a virtual private LAN service is disclosed. Data packets, segments, frames, or other forms of encapsulation may be mirrored off of a core network (e.g., IP, TCP) to one or more mirroring destinations without using a parallel network. Encapsulation techniques are provided that enable packets to be mirrored and transmitted across services such as VPLS, MPLS, and others to a mirror destination. Once received at the mirror destination, mirrored packets may be used for troubleshooting in a more efficient and less resource and time-consuming manner.

Abstract: A device and method for autonomously deciding whether or not to execute data processing requests (commands) from other devices is provided. A rule mapping processor for determining whether or not to executed data processing based on data processing requests received from other devices is also provided. A determination is made at said rule mapping processor as to whether or not to execute data processing based on data transmission mode information for received data processing requests. Determination of execution or non-execution of autonomous processing is possible with this configuration so that in distributed data processing occurring at, for example, a P2P-connected network configuration etc., it is possible to eliminate procedures such as selection of nodes executing processing and therefore enable efficient data processing, packet transmission accompanying deciding of processing nodes can be reduced, and reduction of network traffic may also be made possible.

Abstract: A method and apparatus for requesting bandwidth allocation and allocating a bandwidth in response to the request in a communication system are provided, in which an mobile station detects a second CID requiring bandwidth allocation, the second CID being different from a first CID included in a MAC header, generates a grant management subheader including an order field and a bandwidth field, the order field being for writing a rank of the second CID in a CID list listing CIDs of the mobile station according to a predetermined criterion and the bandwidth field being for writing a bandwidth required for the second CID, concatenates the grant management subheader to the MAC header, and transmits the concatenated MAC header and grant management subheader to a base station to request bandwidth allocation for the second CID.

Abstract: A method for processing a chain of packets involving obtaining the chain of packets from a network, obtaining destination information from a first packet in the chain of packets, determining whether destination information of the first packet matches destination information of a second packet in the chain of packets, aggregating the first packet and the second packet to obtain an aggregated chain of packets, if destination information of the second packet matches the destination information of the first packet, hashing destination information to obtain a hash value, and forwarding the aggregated chain of packets to at least one client using the hash value.

Abstract: For steady state voice data packet transmission between a mobile station and a packet data service node a new compressed TCP/IP header (160) concatenated with a compressed RTP/UDP header (4) is sent. This concatenated header is seven bytes in length instead of the typical 40 byte long RTP/UDP/IP header. A new TCP header arrangement (30) transmits a special access code (161) to a Van Jacobson TCP/IP header compression/decompression arrangement (20). This allows the voice data packet to be transmitted to the receiving end without the other 33 bytes of header information. The PDSN regenerates the IP header and the receiving end then regenerates the RTP/UDP header (205) while it discards the new TCP header arrangement (30).

Abstract: Methods and apparatus for establishing an optimized route between a Mobile Node and a Correspondent Node are disclosed. In particular, a Correspondent Node is notified of the location of a Mobile Node, thereby enabling the Correspondent Node to communicate directly with the Mobile Node. This is accomplished by sending a HOTi message protected in IPSec transport mode from the Mobile Node to a Home Agent associated with the Mobile Node for modification and transmission of a modified HOTi message to the Correspondent Node. The Mobile Node then receives a HOT message protected in IPSec transport mode from the Home Agent associated with the Mobile Node, the HOT message being received from the Home Agent associated with the Mobile Node after modification has been performed by the Home Agent on an initial HOT message received by the Home Agent from the Correspondent Node.

Abstract: When a first mobile node is moved, it reports binding information including a compatible node identifier (virtual mobile guaranteed general network identifier and a node identifier) and a compatible position identifier (mobile guaranteed real network identifier identified on a network to which the first mobile node is moved, and a node identifier) to a first server which is assigned to the first mobile node. A second mobile node also reports the binding information to a second server. For communicating with the second mobile node to which a second server is assigned, if the destination address of a packet addressed to the second mobile node is designated with a compatible node identifier, the first mobile node acquires the binding information of the second mobile node from the second server.

Abstract: Method for processing content of an Internet Protocol (IP) packet and method for processing a full broadcast IP packet. Processing content of an IP packet includes: extracting IP source and destination addresses and payload from the IP packet; and generating an IP frame encapsulating the IP source and destination addresses and the payload between a preamble field and an error checking field. Processing a full broadcast IP packet includes: receiving the full broadcast IP packet including an IP source address and a full broadcast IP destination address; ascertaining a closest matching IP address and a subnet thereof in a switching table of an IP switch; replacing the full broadcast IP destination address in the IP packet with a subnetted source address generated by applying the subnet mask to the IP source address; transmitting the IP packet to all IP addresses in the switching table within the subnetted source address.

Abstract: A packet transfer apparatus which can switch a communication path for each of a plurality of users using the same L2TP tunnel is provided. Packet transfer apparatuses terminating L2TP contain a table specifying a flow threshold level and a priority level of each subscriber; the amount of packet flow of each subscriber is measured in accordance with the information in the table; if the threshold level is exceeded, the packet communication path is switched in accordance with the priority level specified for each subscriber. The OSPF protocol is used to manage the path information, and the information of a plurality of paths to a destination is stored in a path management table. The path is switched by specifying destination routers with the source routing option in the IP header of a packet after L2TP encapsulation.

Abstract: Passive information devices are networked by formulating a network address for the information devices by combining a network address of an associated network node with at least a portion of a unique code of the passive information device.

Abstract: A method for communication includes encapsulating multiple data packets, which carry data and have respective drop precedence (DP) values selected from a range of possible DP values, to produce a concatenated frame of a transport protocol. A composite drop precedence (CDP) value is assigned from the range to the concatenated frame using a pseudo-random assignment function that depends on a distribution of the DP values of the data packets in the concatenated frame. The concatenated frame is transported through a communication network using the transport protocol, in accordance with the pseudo-randomly assigned CDP value.

Abstract: A method and structure is disclosed for dispatching appropriate data to a network processing system comprising an improved technique for extracting protocol header fields for use by the network processor. This technique includes basic classification of a packet according to the types of protocol headers present in the packet. Based on the results of the classification, specific parameter fields are extracted from corresponding headers. All such parameter fields from one or more protocol headers in the packet are concatenated into a compressed dispatch message. Multiple of such dispatch messages are bundled into a single composite dispatch message. Thus selected header fields from N packets are passed to the network processor in a single composite dispatch message, increasing the network processor's packet forwarding capacity by a factor of N. Likewise, multiple enqueue messages are bundled into a single composite enqueue message to direct enqueue and frame alterations to be taken on the bundle of N packets.

Abstract: The method is for sending information through a topology. A first and second node each having a first node having a first access port, a second access port and a first uplink connected to a first router and a second router, respectively. A third node is provided that has a first access port and a first uplink, the first uplink of the third node being connected to the second access port of the first node. A first packet is sent via the first access port to the second node. The second node adds a first port number to a tag of the first packet and sends the first packet via the first uplink of the second node to the first access port of the first node. The first node receives the first packet via the first access port of the first node. The first node adds the first port number to the tag and adds a first port number of the first access port of the first node to the tag. The first node sends the first packet via the first uplink of the first node to a first router.

Abstract: A Fast Reroute implementation suitable for use in a label switched router. Reroute from protected tunnels to backup tunnels may be achieved in constant time irrespective of the numbers of protected forwarding equivalence classes and protected tunnels.

Abstract: A packet transmission system includes a home agent providing a home link and a home address to a mobile node, one or more access routers, each providing a foreign link and a c/o address to the mobile node, and one or more mobility support routers that relay a packet to the destination between the mobile node and the home agent or a counterpart correspondent node. When the mobile node moves into a new foreign link, the corresponding access router transmits a registration request to the home agent and/or the correspondent node. When acquiring a registration request on the way to the destination, each mobility support router stores an entry having the home address of the mobile node and the c/o address contained in the registration request, and produces and transmits a new registration request updating the c/o address to its own address.

Abstract: A mobile router is configured for generating a local router prefix (i.e., a null or invalid address prefix that is not reachable via a wide area network) for use by mobile nodes that attempt to attach to the mobile router. The mobile router attaches to an attachment router using a care-of address with an attachment router address prefix, and outputs a router advertisement message that specifies the null address prefix. Upon receiving a message from a mobile host that includes a source address field specifying a mobile host care-of address that includes the null address prefix, the mobile router adds the mobile host care-of address to a reverse routing header and inserts its own care-of address into the source address field. The message is output to its destination with the reverse routing header, ensuring the IPv6 address of the mobile router remains anonymous in the wide area network.

Abstract: Disclosed is a method and circuit for synchronizing dual data buses. In one embodiment, the method includes a receiving circuit receiving first and second streams of multibit data portions transmitted via first and second parallel data buses, respectively, coupled thereto. The receiving circuit compares first-stream multibit data portions with a first predefined multibit data portion to identify a first-stream multibit data portion that matches the first predefined multibit data portion. The receiving circuit stores into a first FIFO, all first-stream multibit data portions that follow the identified first-stream multibit data portion. The receiving circuit also compares second-stream multibit data portions with a second predefined multibit data portion to identify a second-stream multibit data portion that matches the second predefined multibit data portion.

Abstract: An arrangement and method for reducing memory usage for communications between servers in a communication network utilizing the Session Initiation Protocol (SIP) by controlling establishment of SIP-Tunnels. A single SIP-Tunnel for a certain event package is utilized for multiple subscriptions between one instance of a requesting server such as a Resource List Server (RLS) and one instance of an Application Server such as, for example, a Presence Server. The SIP-Tunnel is then used to send all SIP NOTIFY messages between these two entities to reduce memory usage at both ends by removing the overhead created by SIP.

Abstract: A method and apparatus for processing at least two types of payloads received at varying intervals in a communications network using a single processing path is provided. The two types of payloads may include virtually and contiguously concatenated payloads according to SONET/SHD architecture. The method comprises assigning pseudo indices to payloads having no indices associated therewith and providing both sets of payloads, including indices and pseudo indices, to the single processing path.

Abstract: An efficient Reverse Path Forwarding (RPF) check mechanism is disclosed. In one embodiment, when a network node receives a multicast packet on an incoming interface, the network node obtains an expected incoming interface identifier from either a unicast routing table or a multicast forwarding information table. A RPF Flag stored in association with multicast flow information determines from which table the interface identifier is obtained. If the expected incoming interface does not match the actual incoming interface, the multicast packet is discarded.

Abstract: A method, apparatus, and computer-readable media for transferring data through a switch having a memory, a plurality of ports, and a plurality of address databases storing MAC addresses for devices in communication with the switch, each address database having a different database number comprises receiving a frame of the data on a port of the switch, the port associated with one of the address databases, the frame comprising a destination MAC address; hashing the destination MAC address, thereby producing a hashed MAC address; combining the hashed MAC address and the database number of the address database associated with the port that received the frame, thereby producing a bucket address, the bucket address identifying a plurality of bin addresses, wherein each of the bin addresses identifies a bin in the memory storing a MAC address and a port identifier that identifies one of the ports in the switch; searching the bins for a MAC address matching the destination MAC address; and transmitting the frame to

Abstract: A system and method provide for efficient classification of long strings of data, such as network messages. The system, which may be a classification engine for use in a network device, is configured to include one or more stages having one or more banks of ternary content addressable memories (TCAMs). The TCAM banks of each stage are organized into one or more groups and each group processes the network messages for a different set of the network device's ports. The system further includes at least one memory resource that is shared by the TCAM banks of all groups. That is, the parallel banks of TCAMs operate in a distributed fashion while the shared memory resource operates in a centralized fashion. Accordingly, the system can process network messages at high speed while minimizing the number of required components.

Abstract: A device includes an input processing unit and an output processing unit. The input processing unit dispatches first data to one of a group of processing engines, records an identity of the one processing engine in a location in a first memory, reserves one or more corresponding locations in a second memory, causes the first data to be processed by the one processing engine, and stores the processed first data in one of the locations in the second memory. The output processing unit receives second data, assigns an entry address corresponding to a location in an output memory to the second data, transfers the second data and the entry address to one of a group of second processing engines, causes the second data to be processed by the second processing engine, and stores the processed second data to the location in the output memory.

Abstract: The capacity and coverage of a packet-based conversational service in a mobile communications system is increased by efficiently provisioning resources for packets that have different length headers transported over the radio interface during the period over which the service is provided. A radio bearer or connection is established between a mobile radio and a radio network to support a packet-based conversational service. The radio bearer or connection is normally configured with radio resources to deliver a particular quality of service assuming that the packet headers will be highly compressed. The length of packets to be transmitted via the radio bearer is checked. Those packets which are longer because of less header compression are detected. Processing is performed to minimize or reduce that impact on system capacity or coverage when the detected packets are transmitted over the radio bearer or connection.

Abstract: A communication device for compressing packets includes a first interface, a grouping module and a second interface. The first interface receives packets from a group of media streams, the grouping module generates a group packet that includes a group identifier as well as the payloads of the packets, and the second interface communicates the group packet for receipt by a remote device. A communication device for decompressing packets includes a memory, an interface, and a processor. The memory stores state information for a group of media streams, the interface receives a group packet carrying payloads from the media streams, and the processor reconstructs the headers of the packets using the state information.

Abstract: A communication node comprises a receiver for receiving packets and a routing device for routing the received packets to one of two output ports. For each output port, the communication node further comprises a classifier for classifying a received packet based on its traffic characteristic and storing that packet in a corresponding queue for that traffic characteristic, and a concatenated packets preparer for concatenating n received packets from each queue to form a concatenated packet to be transmitted by the associated output port, where the maximum of n is determined based on the traffic characteristic of the associated queue.

Abstract: A global path identifier is assigned to each explicit route through a data communication network. The global path identifier is inserted into each packet as the packet enters a network and is used in selecting the next hop. When encountering a new selected path, an ingress router sends an explicit object to downstream nodes of the path to set up explicit routes by caching the next hop in an Explicit Forwarding Information Base (“EFIB”) table. Ingress routers maintain an Explicit Route Table (“ERT”) that tracks the global path identifier associated with each flow through the network. Multiple flows using the same path can be implemented by sharing the same global path identifier. In case of sudden network load changes, rerouting can be performed by changing the global path identifier associated with those flows that need to be rerouted and by then transmitting a new path object to downstream nodes.

Abstract: In a method of transmitting user data over a synchronous digital communication network (SDH), the user data are packed in multiplex units by a peripheral device (10; 40). If a greater bandwidth than the capacity of the multiplex unit is required, several multiplex units are contiguously concatenated (VC-4-4c) and transmitted in a common transport module (STM-4). At the gateway to the synchronous communication network, the contiguous concatenation of the multiplex units (VC-4-4c) is converted to a virtual concatenation of multiplex units (VC-4-Nv). To adapt the number of concatenated multiplex units to the bandwidth actually required, only part of the multiplex units are filled with user data, and during the conversion, those multiplex units which are not filled with user data are omitted.