Abstract: Provided are a method and a system for transmitting mobile IP packets without loss. The method includes the steps of storing, by an old radio access station, packets that are not transmitted to a mobile terminal when a handover indication message is received, and creating, by the old radio access station, a tunnel to a new radio access station, and transmitting the stored packets to the new radio access station via the tunnel when a link-layer handover procedure is completed. Thus, upon the handover of the mobile terminal, IP packets directed to the old access control router and the old radio access station are stored in the buffer and then transmitted via the tunnel after the handover, thereby preventing loss of packets during the handover. Thus, yield cannot be degraded upon the handover and seamless network connection service can be provided.

Abstract: A handover control method and apparatus are provided to efficiently buffer packets in a Mobile Worldwide Interoperability for Microwave Access (WIMAX) network. A serving radio access station (S-RAS) and an access control router (ACR) divide and buffer packets to be sent to a mobile station before and after a predetermined message exchange process. The Access control router (ACR) sequentially tunnels a packet buffered in the serving radio access station (S-RAS) and a packet buffered in the Access control router (ACR) into a target radio access station (T-RAS) when a handover for the mobile station is completed. Since an unnecessary buffering operation is not performed in the Access control router (ACR) and the radio access station (RAS), a resource waste may be avoided.

Abstract: A system and method for controlling layer 3 (L3) handover of a mobile node is disclosed. A mobile Internet protocol (MIP) network includes a plurality of mobile nodes, a plurality of users, a plurality of routers, and a handover control system. The plurality of routers periodically report state information of a plurality of base stations and the plurality of routers to a handover control system, which receives the state information to produce a handover topology map and maps a current location of the plurality of mobile nodes to the handover topology map to search for a plurality of target routers having a highest probability of handover. The handover control system transmits the state information of the searched target routers to the mobile nodes. Thus, the L3 handover time can be shortened to tens of ms or less, allowing for seamless real-time multimedia service even though a terminal moves.

Abstract: An Ethernet passive optical network provides a subscriber with a high speed and large capacity data service and a real time digital broadcast/video service. The network includes an optical line terminal for frame-multiplexing broadcast/video signals, which are obtained by performing a switching operation and a time-slot multiplexing with respect to a plurality of digital broadcast/video data delivered from external broadcasting vendors according to broadcast/video selection information delivered from each user, and communication data delivered through an Internet protocol network.

Abstract: A handover control method and apparatus are provided to efficiently buffer packets in a Mobile Worldwide Interoperability for Microwave Access (WIMAX) network. A serving radio access station (S-RAS) and an access control router (ACR) divide and buffer packets to be sent to a mobile station before and after a predetermined message exchange process. The Access control router (ACR) sequentially tunnels a packet buffered in the serving radio access station (S-RAS) and a packet buffered in the Access control router (ACR) into a target radio access station (T-RAS) when a handover for the mobile station is completed. Since an unnecessary buffering operation is not performed in the Access control router (ACR) and the radio access station (RAS), a resource waste may be avoided.

Abstract: Provided are a method and a system for transmitting mobile IP packets without loss. The method includes the steps of storing, by an old radio access station, packets that are not transmitted to a mobile terminal when a handover indication message is received, and creating, by the old radio access station, a tunnel to a new radio access station, and transmitting the stored packets to the new radio access station via the tunnel when a link-layer handover procedure is completed. Thus, upon the handover of the mobile terminal, IP packets directed to the old access control router and the old radio access station are stored in the buffer and then transmitted via the tunnel after the handover, thereby preventing loss of packets during the handover. Thus, yield cannot be degraded upon the handover and seamless network connection service can be provided.

Abstract: An Ethernet-PON integrates broadcast/communication through time division multiplexing, which provides users with high-speed, high-volume communication data and high-quality, real-time digital broadcast/image data. An OLT performs a switching operation on a plurality of digital broadcast/image data received from an external broadcaster according to respective broadcast/image selection information from users, time-division-multiplexes the data into a broadcast/image signal, multiplexes the signal and communication data from an IP network into a frame, and electro-optically converts the frame and transmits to the frame to ONTs through an optical splitter. Each ONT receives and photoelectrically converts the signal from the OLT, and performs frame & time-slot demultiplexing to output the entire received communication signals and broadcast/image information contained in a time-slot assigned to the ONT to a corresponding user.

Abstract: A system and method for controlling layer 3 (L3) handover of a mobile node.

Abstract: In a system and method for managing a complex network, including an access network, a metro network, or the like, the method includes the steps of: requesting, at a first terminal, call set-up to perform the Voice over Internet Protocol (VoIP) call with a second terminal; collecting available bandwidth information of an access network to which each of the first and second terminals belongs, and available bandwidth information of a metro network linked to the access network; and allowing the call set-up request when the available bandwidths of the access network and the metro network are larger than a bandwidth for the VoIP call. Accordingly, resources and performance of the complex network can be continuously controlled, and a high-quality and large-capacity service Quality of Service (QoS) guarantee can be provided.

Abstract: In a system and method for guaranteeing quality of service (QoS) of a multicasting service, when a multicasting source or a receiving terminal is newly registered, or a router or the receiving terminal leaves an existing multicasting group, a topology and a resource state of a network is retrieved, and a determination is made as to whether to provide a new multicasting service based on the retrieved network resource state. Thus, multicasting-based high-quality multimedia service can be provided to users.

Abstract: A virtual private network (VPN) based on a multi protocol label switching (MPLS) technique is established by an MPLS-based VPN providing apparatus and method. The MPLS-based VPN providing apparatus and method are capable of simplifying the use of protocols, reducing a load, and guaranteeing quality of service (QoS) by adopting a centralized control structure.

Abstract: In an apparatus for a performance management of a label switching path (LSP) set in a multi protocol label switching (MPLS) network and a method thereof, a determination is made as to whether the LSP satisfies a required performance criterion in the network, and protection of the LSP or replacement of the LSP not satisfying the required performance with a substitute LSP is carried out.

Abstract: A centralized control apparatus and a method thereof manages an Multi Protocol Label Switching (MPLS) network, in which the centralized control apparatus performs Label Switched Path (LSP) setting of the MPLS network and management for set LSP, to reduce a load of the MPLS network generated upon setting LSP and to reduce a time for setting the LSP, and to improve management efficiency for the set LSP.

Abstract: A bi-directional optical add-drop multiplexer is disclosed. The multiplexer includes at least two couples of optical elements including a wavelength division multiplexer and an optical circulator. Each of the wavelength division multiplexer demultiplexes one of a first WDM optical signal and a second WDM optical signal transmitted in opposite directions through one optical transmission line between nodes of a bi-directional WDM optical communication network, drops an optical signal having a predetermined wavelength from the demultiplexed signals, and adds an optical signal having a predetermined wavelength to the other of the first WDM optical signal and the second WDM optical signal. The optical circulator separates routes for the signals dropped and added by a corresponding wavelength division multiplexer. The bi-directional optical add-drop multiplexer can prevent or reduce degradation of optical signal transmission quality due to crosstalk between an added optical signal and a dropped optical signal.

Abstract: An Ethernet passive optical network provides a subscriber with a high speed and large capacity data service and a real time digital broadcast/video service. The network includes an optical line terminal for frame-multiplexing broadcast/video signals, which are obtained by performing a switching operation and a time-slot multiplexing with respect to a plurality of digital broadcast/video data delivered from external broadcasting vendors according to broadcast/video selection information delivered from each user, and communication data delivered through an Internet protocol network.

Abstract: An Ethernet-PON that accommodates real-time broadcast/image signals and provides security for broadcast/image signals, allows user authentication without a CAS. An OLT in the Ethernet-PON switches digital broadcast/image data signals from a broadcaster according to respective broadcast/image selection information of users, and scrambles the switched broadcast/image data on a user-by-user basis. The scrambled data is multiplexed and converted to a broadcast/image optical signal, which is transmitted, combined with a communication signal from an IP network, to ONTs through an optical splitter. The ONTs select broadcast/image data from the broadcast/image signals according to the respective broadcast/image selection information.

Abstract: An Ethernet-PON integrates broadcast/communication through time division multiplexing, which provides users with high-speed, high-volume communication data and high-quality, real-time digital broadcast/image data. An OLT performs a switching operation on a plurality of digital broadcast/image data received from an external broadcaster according to respective broadcast/image selection information from users, time-division-multiplexes the data into a broadcast/image signal, multiplexes the signal and communication data from an IP network into a frame, and electro-optically converts the frame and transmits to the frame to ONTs through an optical splitter. Each ONT receives and photoelectrically converts the signal from the OLT, and performs frame & time-slot demultiplexing to output the entire received communication signals and broadcast/image information contained in a time-slot assigned to the ONT to a corresponding user.