Abstract: A method is disclosed for transmitting and receiving packetized data having multiple protocol headers in a packet data communication system. An operating state of a network is determined, and a period for transmitting a full packet is decided according to a result of the determination. Full packets having uncompressed headers are transmitted during periodic transmission times according to the decided full-packet transmission period, and compressed packets are transmitted in other transmission times. If the operating state of the network is decided to be a congested state according to an average packet retransmission ratio produced in a period for measuring the operating state of the network, the full-packet transmission period is set to “1”. A value of the full-packet transmission period in an unloaded state is twice a value of the full-packet transmission period in a normal state.

Abstract: Disclosed are an apparatus and a method for performing state transition of a backup router in a router redundancy system comprising a master router and at least one backup router for routing hosts. The method includes the steps of determining if a master router has a fault, and shifting the backup router into a master state if the master router has a fault and replacing a address of the backup router with a address of the master router in such a manner that the backup router operates with the replaced addresses.

Abstract: A redundancy method and apparatus for a default router of hosts in a local area network (LAN). The router redundancy system includes an active router and at least one standby router. The active router transmits a periodic advertisement message. The standby router determines whether a periodic advertisement message is received from the active router within a predetermined timeout period, and repeatedly transmits a heart beat message to the active router a predetermined number of times if the advertisement message is not received. After repeated transmission of the heart beat message, the standby router transitions to an active state if a response to the heart beat message is not received within a predetermined waiting time.

Abstract: A method is disclosed for transmitting and receiving packetized data having multiple protocol headers in a packet data communication system. An operating state of a network is determined, and a period for transmitting a full packet is decided according to a result of the determination. Full packets having uncompressed headers are transmitted during periodic transmission times according to the decided full-packet transmission period, and compressed packets are transmitted in other transmission times. If the operating state of the network is decided to be a congested state according to an average packet retransmission ratio produced in a period for measuring the operating state of the network, the full-packet transmission period is set to “1”. A value of the full-packet transmission period in an unloaded state is twice a value of the full-packet transmission period in a normal state.