实务-7（Practice -7）.docVIP

实务-7（Practice -7） 1. network protocol elements, each element involved in what areas: Answer: (1) syntax: information related to data and control the format, encoding and signal level etc. (2): semantic error handling for coordination and control information (3): to speed synchronous matching and ranking etc. 2. the exchange node has basic function Answer: (1) can be correctly received and analyzed from the subscriber line and the trunk line to send the call signal (2) can correctly receive and analyze the address signals sent from the user line and the trunk line (3) according to the destination address of the correct routing and forwarding signals at the relay line (4) to control the connection establishment (5) according to the release signal by connection removed The 3. basic principle of message exchange Answer: the basic principle: store and forward, a thermal data is first sent to the source node switch, the switch will store information, determine the route according to the destination address, the automatic processing, then the information is sent to the outgoing line line, once the idle channel will message to the next switch, the user knows the end point. 4.DXC how to define? Answer: DXC is the transmission node equipment intelligent exchange of digital signal and its sub group rate signal, it is the 1.5 permanent connection, input and output flow of digital cross connect multiplexer and distribution frame controlled by computer. 5.DXC (m/n) represents what mean? Answer: the equipment named DXC as DXCm/n, which represents the highest level of input digital multiplexing m stream, n said the lowest level can reuse cross connect digital stream. M is a numerical range: 1-6; n:0-6; specific meaning: 1 2Mbit/s 2 8Mbit/s 3 34Mbit/s 4 140Mbit/s 5 622Mbit/s 6 2.5Gbit/s 6. frame relay packet switching with the difference? Answer: frame relay and packet switching is similar, but with larger capacity than the packet frame as a unit rather than data transmission by gro