Abstract: Communication switching apparatus for providing communication between a multiplicity of digital information processors, the apparatus including a plurality of ports each communicating with at least one of the multiplicity of digital information processors, and a port interconnector operative to provide communication between more than one pair of ports from among the plurality of ports, characterized in that, when an overflow of information is caused at the port interconnector or at one of the plurality of ports, an overflow indication is provided to the digital information processors which communicate with the port interconnector or with the overflowed one of the plurality of ports.

Abstract: A network having a security capability where the network includes a data bus, a plurality of stations connected to the data bus and a security unit which monitors traffic on the data bus and only enables authorized data to flow along the data bus.

Abstract: A method for secure transmission of data having a destination address and a source address on a shared communication network comprising the steps of transmitting a multiplicity of data frames, each containing at least an encrypted data sequence employing the destination address as at least part of a decryption key therefor, receiving the multiplicity of data frames at a receiver on the shared communication network and attempting to decrypt the encrypted data sequence by employing the local address of the receiver as at least part of a decryption key.