Abstract: A multi-port network communication device includes a plurality of ports for the reception and transmission of addressed data packets which include media access control address data, a forwarding mechanism for directing packets received at any of said plurality of ports to at least one of the plurality of ports, a memory for the selectively controllable storage of permitted media access control addresses, and means for restricting forwarding of packets from the device in response to an examination of media access control data in said packets and said permitted media access control addresses. The forwarding of a unicast packet having a source address and a destination address is prevented when neither of those addresses in the unicast packet corresponds to a permitted media access control address. The forwarding mechanism prevents the forwarding of multicast or broadcast packets to ports which are not connected to devices having permitted media access control addresses.

Abstract: A master-slave switch method for reversing roles between nodes in a network environment when the traditional role reversal functionality as defined by the network specification is not implemented within the node is presented. A data terminal which does not support the traditional master-slave switch functionality, progresses as far as establishing an asynchronous connectionless (ACL) connection. The LAN access point then request a role switch, when the reversal of roles fails, the connection is aborted with device addresses of the participating entities being stored. The LAN access point then initiates the reestablishment of the connection in a master role with the data terminal assuming a slave role after verification of the device address of the LAN access point.

Abstract: A link aggregator control which produces for a system in which the aggregator is located data units identifying the system and a partner identity for a partner system, and in response to a change from an old system identity to a new system identity produces data units identifying the new system identity and distinctively identifying the old system identity in place of the partner identity. Where the system identity and partner identity are each in the form of a globally administered unicast media access control the old system identity is represented in the form of a locally administered multicast address in place of the partner identity.

Abstract: A master-slave switch method for reversing roles between nodes in a network environment when the traditional role reversal functionality as defined by the network specification is not implemented within the node is presented. A data terminal which does not support the traditional master-slave switch functionality, progresses as far as establishing an asynchronous connectionless (ACL) connection. The LAN access point then request a role switch, when the reversal of roles fails, the connection is aborted with device addresses of the participating entities being stored. The LAN access point then initiates the reestablishment of the connection in a master role with the data terminal assuming a slave role after verification of the device address of the LAN access point.

Abstract: A link aggregator control which produces for a system in which the aggregator is located data units identifying the system and a partner identity for a partner system, and in response to a change from an old system identity to a new system identity produces data units identifying the new system identity and distinctively identifying the old system identity in place of the partner identity Where the system identity and partner identity are each in the form of a globally administered unicast media access control the old system identity is represented in the form of a locally administered multicast address in place of the partner identity

Abstract: A multi-port network communication device includes a plurality of ports for the reception and transmission of addressed data packets which include media access control address data, a forwarding mechanism for directing packets received at any of said plurality of ports to at least one of the plurality of ports, a memory for the selectively controllable storage of permitted media access control addresses, and means for restricting forwarding of packets from the device in response to an examination of media access control data in said packets and said permitted media access control addresses