Abstract: A method and device for controlling security of a communication channel between an OLT and an ONU in a secure channel control system of EPON formed of the OLT and the ONU having a cryptographic module, a key management module and a transmitter/receiver for transmitting/receiving frames, the method comprising the steps of: a) distributing a key between the OLT and the ONU; b) transferring the distributed key to the encryption modules of the OLT and ONU; c) activating a corresponding encryption module using the distributed key at one of the OLT and the ONU which starts a security function activation; d) transmitting an encryption module information message including activation state information of the corresponding encryption module from the side (transmitting side) having the activated encryption module to an opponent side (receiving side); and e) activating an encryption module by checking activation state information of the encryption module at the receiving side.

Abstract: A method for a first mobile station to transmit a safety message to a second mobile station is provided. The first mobile station competitively transmits a non-safety message to the second mobile station during a first period. The first mobile station spreads a safety message and generates a spread message when a second period starts, and transmits the spread message to the second mobile station. Accordingly, safety message transmission delay or data loss in the inter-vehicle communication can be prevented.

Abstract: Disclosed herein is a variable length packet switching system. The variable length packet switching system includes at least two switching means, a plurality of multiplexing units and a plurality of demultiplexing units. The switching means switch ATM cells or variable length packet data in parallel. The multiplexing means are arranged upstream of the switching means for multiplexing data inputted from a line card to the switching means in packet units and dividing a packet into packets of a number corresponding to the number of the switching means. The demultiplexing means are arranged downstream of the switching means for combining packets inputted after being switched in parallel by the at least two switching means and outputting the combined packet converted into a format adequate to the line card.

Abstract: An apparatus and method for providing a security function of frames transmitted between optical network terminals (OLTs) and optical network units (ONUs) in an Ethernet passive optical network (EPON) providing media access control (MAC) services are provided.

Abstract: A data transmission system in an EPON includes a parser classifying frames generated in each block, and transmitting the frames to a block. A scheduler performs multiplexing of frames, then, during a transmission time permitted by an OLT, determines a transmission sequence of the frames and transmits the frames. A MPCP slave processes messages transmitted from the OLT, generates response messages on the transmitted messages, and maintains time synchronization with the OLT A processor interface conveys frames transmitted from the OLT to a processor, frames primitives transmitted from the processor, and transmits the primitives to the OLT. A register stores a value used during generation of frames in each block, a value for system control, and a value acquired from MPCP control frames.

Abstract: A communication system using a layering architecture that supports peer-to-peer communication between ONUs in an Ethernet-based PON. The system includes a physical layer receiving frames from an OLT; and data link layers including an emulation layer, a MAC layer, a MAC control layer, and a MAC emulation layer. The data link layers further include a P2PE layer for generating and managing an address table that matches PON-tags of frames received from ONUs and transmission point addresses, and a mirror address table of the address table, and an FRM layer for performing, according to a target address of the frames, an upstream process that transmits frames to an upper layer and a downstream process that transmits frames to a lower layer.

Abstract: Disclosed herein is a variable length packet switching system. The variable length packet switching system includes at least two switching means, a plurality of multiplexing units and a plurality of demultiplexing units. The switching means switch ATM cells or variable length packet data in parallel. The multiplexing means are arranged upstream of the switching means for multiplexing data inputted from a line card to the switching means in packet units and dividing a packet into packets of a number corresponding to the number of the switching means. The demultiplexing means are arranged downstream of the switching means for combining packets inputted after being switched in parallel by the at least two switching means and outputting the combined packet converted into a format adequate to the line card.