Data communication device

Introduction

data communication device is a data communication system generic name switching equipment, the transmission device and the terminal device, refers to the use of electromagnetic or optical cable, wireless, transmission, reception or transmission of binary data telecommunications equipment consisting of hardware and software systems. Comprising: a data terminal, Frame Relay equipment, ATM switches, ISDN switching system, the soft switch device, the routing device, IP telephony gateway and gatekeeper, a network access server, LAN management, digital cross-connect equipment, DDN equipment, Ethernet switching equipment, media gateway equipment.

in a packet-switched network, for example, feature points such as facilities, data communication device has relay packet switch (the PTS), a local packet switch (PTLS), the packet concentrator (the PCE), packet assembly and disassembly equipment ( the PAD), network management Center (the NMC), data transmission equipment and data terminal equipment; network as to the position of the switch points, the data communication device can be divided into an ISC, a switching center, the switching center and the user two concentrators .

structure

typical packet switching network circuit construction shown in Fig.

in an ISC switches typically used with a switching center location co-located in a packet switch, the visual development needs international business, separately provided dedicated international gateway office switch. In order to meet the special needs of certain areas of external communications, reduce network roundabout, also set regional office entrances and exits, entrances and exits general regional office used a switching center switch and the location co-located.

may be provided a large capacity switching center and local transit unity packet switch (PTS / PTLS), in transit particularly large city transit packet switch may be provided, for accelerating the traffic the dredge.

two local and transit switching center is provided unity packet switch (PTLS), primary transfer and clear the access service users in the region.

is widely used packet switching device of DPN-100 series.

packet concentrator (PCE) of a user terminal suitable for small city or region, or large enterprises and institutions are concentrated in the user, the user terminal set. Packet concentrator is a centralized user terminal, and a switching center interconnected with the device. Less suitable for the user terminal city or region, it can also be used for user-intensive and relatively scarce building line or cell.

packet multiplexing device is a detachable device having a packet assembly and disassembly function, referred to as PAD. It is non-packet mode terminal equipment into the intermediate sub-network. Its function is a packet assembly and disassembly, acting both as a collection of information, protocol conversion action underway. Packet assembly and disassembly device generally concentrated for users building, synchronous or asynchronous end user may be provided simultaneously.

Network Management Center (NMC) is a computer system to manage the entire network. Centralized network management and decentralization way, its main function is network monitoring, fault detection and parameter measurement alarm reporting, network utilization and load conditions, collecting charging information parameter management, and user links, network management software, network hardware and software maintenance management, measurement and collection of statistical information, and so on.

data transmission equipment including a modem (baseband sub-band, and, two), the data service unit, time division multiplexing or the like.

many kinds of data terminal equipment, but generally can be divided into packets terminal (PT) and non-packet mode terminals (NPT) categories. Packet mode terminal has: a main computer, a digital facsimile, teletex terminal, the PAD user, user group or a concentrator switch, PBX users, Videotex access device (the VAP), a local area network (LAN) and a variety of special terminals; non-packet mode terminals (NPT) has: a microcomputer terminals, videotex terminal (videotex), telex terminal and a variety of special terminals.