Abstract: A method of transmitting OSI layer 2 datacoms data by direct incorporation into a plurality of synchronous digital hierarchy virtual containers is disclosed, in which a higher bit rate OSI layer 2 data frame is multiplexed into a plurality of lower bit rate SDH (or SONET) virtual containers, which are transmitted simultaneously and in parallel over a synchronous communications network. The plurality of virtual containers are virtually concatenated by association of the payloads of the plurality of virtual containers. Re-assembly of the OSI layer 2 data frames from a plurality of virtually concatenated VCs is achieved by storing each received VC payload corresponding to an OSI layer 2 data frame in a corresponding respective memory location, and alternately reading interleaved bytes from the plurality of payloads under control of a plurality of read pointers.

Abstract: A frame based data communications network is interfaced to a synchronous digital hierarchy network via a plurality of frame based data port cards incorporated into a plurality of synchronous multiplexers. Each port card comprises a conventional frame based data port, a frame switch, a rate adapter means and a mapping means for mapping data frames into a plurality of SDH virtual containers. Frame based data is incorporated directly into a synchronous virtual container without encapsulation in an intermediate protocol. A number of topologies of a frame based data channel network are possible, overlaid on the underlying synchronous transport network, including an open loop topology, a ring mode topology, and a backhaul topology.

Abstract: The present invention relates to data tunnelling and in one embodiment to the tunnelling of IP (Internet Protocol) data across an OSI (Open Systems Interconnect) network. In the preferred embodiment, network elements include both an OSI stack and an IP stack, and a respective directory of OSI addresses and corresponding IP subnets. Each network element generates a routing data packet, conveniently a Link State Packet (LSP), which includes the OSI address and IP subnet(s) associated with that network element. The LSPs are distributed across the network in normal manner. Upon receipt of an LSP from another network element, each network element updates its respective directory in respect of said other network element. Thus, each directory is automatically updated to reflect changes in the network, particularly in respect of IP subnets. This arrangement significantly reduces the need for manual tunnel configuration in the network.

Abstract: The present invention relates to data tunnelling and in one embodiment to the tunnelling of IP (Internet Protocol) data across an OSI (Open Systems Interconnect) network. In the preferred embodiment, network elements include both an OSI stack and an IP stack, and a respective directory of OSI addresses and corresponding IP subnets. Each network element generates a routing data packet, conveniently a Link State Packet (LSP), which includes the OSI address and IP subnet(s) associated with that network element. The LSPs are distributed across the network in normal manner. Upon receipt of an LSP from another network element, each network element updates its respective directory in respect of said other network element. Thus, each directory is automatically updated to reflect changes in the network, particularly in respect of IP subnets. This arrangement significantly reduces the need for manual tunnel configuration in the network.